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1477 Cards in this Set
- Front
- Back
What is the charge on DNA?
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negative
|
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How many subunits make up a nucleosome core?
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Eight; two of each of the four histone types
|
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How many times does the DNA loop around each octamer (nucleosome core)?
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twice
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What is the charge on DNA?
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negative
|
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What histone type is found between the nucleosome cores (the histone octamers)?
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H1
|
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What molecule ties the nucleosomes together in a string?
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H1 histone
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How many subunits make up a nucleosome core?
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Eight; two of each of the four histone types
|
|
How many times does the DNA loop around each octamer (nucleosome core)?
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twice
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What histone type is found between the nucleosome cores (the histone octamers)?
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H1
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What molecule ties the nucleosomes together in a string?
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H1 histone
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During what stage of cell division does DNA condense?
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mitosis
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What is the charge on nucleosomes?
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positive
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True or False: When DNA is condensed, it is transcriptionally active.
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False; condensed DNA (heterochromatin) is transcriptionally inactive
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What are the names of the four subunits of a nucleosome core?
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H2A, H2B, H3 and H4
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Which is less condensed: heterochromatin or euchromatin?
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euchromatin
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What is DNA called when it is condensed and transcriptionally inactive?
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heterochromatin
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True or False: H1 is the only histone that is not found at the nucleosome core.
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true
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What is transcriptionally active DNA called?
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euchromatin
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How many hydrogen bonds are there between adenine and thymine?
|
two
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What are the two purines?
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Adenine and Guanine (PURe As Gold)
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Which is stronger: a guanine-cytosine bond or an adenine-thymine bond?
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A guanine-cytosine bond, because it has three hydrogen bonds; an adenine-thymine bond only has two
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What are the three pyrimidines?
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Cytosine (C), thymine (T), and uracil (U) (remember, CUT the PY [pie]: PYrimidines)
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What physical property do nucleic acids with increasing proportions of guanine-cytosine bonds display?
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higher melting temperature--takes more heat to break the more stable three hydrogen bonds that connect C - G
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How many rings do pyrimidine molecules have?
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1 ring
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What nucleotide has a ketone?
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guanine
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Which three amino acids are necessary for purine synthesis?
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glycine, aspartate, and glutamine
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How many rings do purine molecules have?
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two rings
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What does deamination of cytosine yield?
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uracil
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Nucleoside = _____ + ribose
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nitrogen base
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In what type of nucleic acid is uracil found?
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RNA
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What type of bond links nucleotides?
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3' to 5' phosphodiester bond
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In what type of nucleic acid is thymine found?
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DNA
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What nucleotide has a methyl group?
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thymine (remember THYmine has a meTHYl group)
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How many hydrogen bonds are there between guanine and cytosine?
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three
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Nucleotide = _____ + phosphate
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nucleoside (nitrogenous base + ribose)
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What are the two precursors to creating the pyrimidine ring?
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aspartate and carbamoyl phosphate
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In de novo nucleotide synthesis, _____ (purines/pyrimidines) are made from IMP precursors, while _____ (purines/pyrimidines) are made from orotate precursors.
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purines; pyrimidines
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What is the quality of trimethoprim that makes it a good antibiotic?
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it inhibits bacterial dihydrofolate reductase preventing bacterial DNA synthesis (cannot make thymine)
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Pyrimides are made from orotate precursor, with _____ added later.
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PPRP (phosphoribosyl pyrophosphatase)
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What enzyme converts ribonucleotides to deoxyribonucleotides?
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ribonucleotide reductase
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Why are 6-mercaptopurine, 5-fluorouracil, methotrexate, and hydroxyurea effective antineoplastic agents?
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They interfere with nucleotide synthesis, hindering the ability of neoplastic cells to synthesize DNA
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_____ are synthesized first and converted to deoxyribonucleotides by ribonucleotide reductase.
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ribonucleotides
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Name four drugs that interfere with pyrimidine synthesis.
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methotrexate, 5-fluorouracil, trimethoprim, and hydroxyurea
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dUMP is converted to dTMP by which enzyme?
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thymidylate synthase
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What is the cofactor in the thymidylate synthase reaction?
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methyl tetrahydrofolate- The reaction requires N5N10 methylene THF
|
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_____ regenerates THF by reducing its oxidized form, _____.
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dihydrofolate reductase; dihydrofolate (DHF)
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Converting carbamoyl phosphate into orotic acid requires _____.
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aspartate
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Converting PRPP into IMP requires ______,______,______, and ______.
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glycine, aspartate, glutamine, and tetrahydrofolate (remember these are amino acids needed to make purines, and THF is needed to make any DNA)
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Of the 5 nucleotides (A, C, G, T, U), which is not first made in a monophosphate form?
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cytosine, UDP is converted to CTP
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6-Mercaptopurine (6-MP) blocks de novo ______ (purine/pyrimidine) synthesis.
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purine
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Treatment with 5-fluorouracil, methotrexate, or trimethoprim all affect nucleotide synthesis how?
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decreasing dTMP (thymidine) synthesis
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What enzyme does hydroxyurea inhibit?
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ribonucleotide reductase
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5-Fluorouracil inhibits ______ _____, while methotrexate and trimethoprim both inhibit ______ _____.
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thymidylate synthase; dihydrofolate reductase
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Deficiency in ornithine transcarbamoylase leads to what?
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hyperammonemia (since this enzyme is required in the urea cycle) and increased orotic acid
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Deficiency in either orotic acid phosphoribosyltransferase or orotidine 5' phosphate decarboxylase can lead to what?
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orotic aciduria- characterized by increased orotic acid in the urine, megaloblastic anemia (due to impaired DNA synthesis) and failure to thrive -- there is NO hyperammonemia as neither of these enzymes is involved in the urea cycle. (cannot convert orotic acid to UMP--problem with pyrimidine synthesis)--
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|
What findings are seen in orotic aciduria?
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increased orotic acid in the urine, megaloblastic anemia (due to impaired DNA synthesis) and failure to thrive -- there is NO hyperammonemia (as there is in ornithine transcarbAMoylase (OTC) deficiency)
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|
What is the treatment for orotic aciduria?
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uridine supplement
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What is called when a purine is substituted for a pyrimidine or when a pyrimidine is substituted for a purine?
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transversion
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What is it called when one purine is substituted for the other purine or when one pyrimidine is substituted for the other pyrimidine?
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transition
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What term refers to the fact that each codon in the genetic code specifies only a single amino acid?
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unambiguous
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Where might you see a genetic code that has overlapping genes?
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some viruses
|
|
What does it mean that the genetic code is "degenerate"?
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there are more than one codon that code for the same amino acid
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True or False: The genetic code is universal.
|
true; although there are a few exceptions in archaic life forms)
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What does a commaless, nonoverlapping genetic code entail?
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The entire genome is read from a fixed starting point as a continuous string of bases
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True or False: Methionine is encoded by more than one codon.
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False; methionine is encoded by only 1 codon (AUG)
|
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Methionine is encoded by which codon?
|
AUG = start codon
|
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List four exceptions to the rule that the genetic code is universal.
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mitochondria, archaebacteria, mycoplasma, and some yeasts
|
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Rank the following types of mutations in order of severity: missense, silent, nonsense.
|
most severe: nonsense (codes for stop codon) > missense > silent (least severe-no affect)
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What is it called when a mutation in DNA results in no change to the amino acid that is being coded for?
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Silent mutation
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Silent mutations are often the result of changes in what position of a codon?
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The third position (tRNA wobble)
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What is it called when a DNA mutation yields a changed amino acid?
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missense mutation
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What kind of mutation is a DNA change that results in the misreading of all nucleotides downstream of it?
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frameshift mutation
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What does it mean if a missense mutation is "conservative"?
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The new amino acid has a similar chemical structure as the originally intended one
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A frameshift mutation tends to yield what?
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A truncated, nonfunctional protein
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What is a "nonsense mutation"?
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A DNA change that results in an early-stop codon
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What is the purpose of DNA topoisomerases creating a nick in the DNA helix?
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to relieve tension/supercoils in front of the replication fork-- allowing helicase to continue unzipping
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What type of nucleic acid does primase read from?
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DNA
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How many origins of replication does prokaryotic DNA use? eukaryotic?
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one; multiple
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What is the function of primase?
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It makes an RNA primer on which DNA polymerase III can then initiate replication
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What type of nucleic acid does primase build with?
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RNA
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Which enzymes has exonuclease activity in prokaryotic DNA replication?
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DNA polymerase III (3'--> 5' exonuclease) and DNA polymerase I (5'--> 3' exonuclease)
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In which direction does DNA polymerase III have exonuclease activity?
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3'--> 5' (it is looking over it's shoulder at the last base it put down to make sure it is correct--proofreading)
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What enzyme elongates the chain by building on an RNA primer?
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DNA polymerase III
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When does DNA polymerase III "proofread" the DNA?
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After adding each nucleotide, it "proofreads" it
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Can DNA polymerase III initiate replication without an RNA primer?
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no
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What enzyme degrades the RNA primer during prokaryotic DNA replication?
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DNA polymerase I (5' --> 3' exonuclease)
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In which direction does DNA polymerase III synthesize DNA?
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5' --> 3'
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In what direction does DNA polymerase I excise the RNA primers?
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5' --> 3'
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What enzymes create a nick in the helix?
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DNA topoisomerases (e.g. DNA gyrase)
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True or False: DNA replication is semiconservative.
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true; semiconservative DNA replication produces 2 double helices each composed of one original DNA strand and one new DNA strand
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Is the leading strand synthesized continuously or discontinuously?
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continuously
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Onto which end of the newly synthesized DNA molecule does DNA polymerase III add the next subunit?
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3'
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Is the lagging strand synthesized continuously or discontinuously?
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dicontinuously
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What enzyme seals pieces together during prokaryotic DNA replication?
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DNA ligase
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When does DNA polymerase III stop adding deoxynucleotides to the 3' end?
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When it reaches the primer of the preceding fragment
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Which drug category inhibits DNA gyrase (a specific prokaryotic topoisomerase)?
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fluoroquinolones
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What enzyme has 3' → 5' exonuclease activity?
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DNA polymerase III
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What enzyme has proofreading activity in prokaryotic DNA replication?
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DNA polymerase III
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What is the name of the Y-shaped region along the DNA template where leading and lagging strands are synthesized?
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replication fork
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Which protein unwinds the DNA template at the replication fork?
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DNA helicase
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Where does eukaryotic DNA replication begin?
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origin of replication - a consensus sequence that is rich in AT bases
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What prevents DNA strands from re-annealing once helicase has separated them?
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single stranded DNA binding proteins
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What are the pieces that are formed in discontinuously synthesized DNA called?
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okazaki fragments
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DNA polymerase I and III are (prokaryotic / eukaryotic) enzymes.
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prokaryotic - but there are analogues is eukaryotes
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What enzyme has 5' → 3' exonuclease activity?
|
DNA polymerase I
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True or False: Eukaryotic DNA has more than one origin of replication.
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true
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True or False: The excision-repair-specific glycosylase works on both strands of DNA at once.
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False; it is a single-strand, excision-specific glycosylase
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During nucleotide excision DNA repair, what kind of enzyme first makes a break in the damaged DNA?
|
endonuclease
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During nucleotide excision repair, what is the function of the specific endonuclease?
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removes oligonucleuotides containing damaged base
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True or False: The single-strand, excision-repair-specific glycosylase can recognize damaged bases.
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true
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True or False: The single-strand, excision-repair-specific glycosylase can remove damaged bases.
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true
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True or False: Xeroderma pigmentosum is caused by defects in DNA repair.
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true it is caused by defects in nucleotide excision repair which is supposed to correct thymidine dimers that were created by UV damage
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What is the specific defective DNA repair mechanism in xeroderma pigmentosa?
|
nucleotide excision repair
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During nucleotide excision DNA repair, what enzyme seals the junctions between fragments?
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DNA ligase
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What is the difference between single- and double-strand DNA repair as it relates to DNA homology?
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Double-strand DNA repair is non-homologous and simply attaches fragment ends together, while single-strand repair maintains homology
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True or False: Eukaryotic DNA has more than one origin of replication.
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true
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True or False: The excision-repair-specific glycosylase works on both strands of DNA at once.
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False; it is a single-strand, excision-specific glycosylase
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During nucleotide excision DNA repair, what kind of enzyme first makes a break in the damaged DNA?
|
endonuclease
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During nucleotide excision repair, what is the function of the specific endonuclease?
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removes oligonucleuotides containing damaged base
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True or False: The single-strand, excision-repair-specific glycosylase can recognize damaged bases.
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true
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True or False: The single-strand, excision-repair-specific glycosylase can remove damaged bases.
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true
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True or False: Xeroderma pigmentosum is caused by defects in DNA repair.
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true it is caused by defects in nucleotide excision repair which is supposed to correct thymidine dimers that were created by UV damage
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What is the specific defective DNA repair mechanism in xeroderma pigmentosa?
|
nucleotide excision repair
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During nucleotide excision DNA repair, what enzyme seals the junctions between fragments?
|
DNA ligase
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What is the difference between single- and double-strand DNA repair as it relates to DNA homology?
|
Double-strand DNA repair is non-homologous and simply attaches fragment ends together, while single-strand repair maintains homology
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Patients with xeroderma pigmentosum show excessive sensitivity to what? What organ is most affected?
|
Ultraviolet light; the skin
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What process brings together two nonhomologous ends of DNA and seals them together?
|
Nonhomologous end joining, which is a type of double-stranded DNA repair
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With what pattern is xeroderma pigmentosa inherited?
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autosomal recessive
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The phrase "children of the night" describes patients with _____ ______ due to an increased risk for melanoma and other cancers with exposure to sunlight.
|
xeroderma pigmentosum
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Xeroderma pigmentosa results in an inability to repair what specific DNA error?
|
thymidine dimers
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What commonly causes thymidine dimers to form in DNA?
|
UV light exposure
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What cancer is xeroderma pigmentosa associated with?
|
melanoma
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True or False: Xeroderma pigmentosum is associated with dry skin.
|
true
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What is the first step in the base excision repair of damaged DNA?
|
Specific glycosylases recognize and remove a single damaged base
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In base excision repair, what does the apurinic/apyrimidinic endonuclease do?
|
It cuts the DNA at a apyrimidinic site and removes the empty sugar
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In base excision repair, what enzyme fills the gap?
|
DNA polymerase
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In single-stranded DNA repair, how are nucleotide excision and base excision repair different?
|
During nucleotide repair, the entire nucleotide structure is removed and replaced; during base excision repair, the base is clipped off of the sugar and repaired without the whole backbone of the DNA being taken apart
|
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In single-stranded DNA mismatch repair, how does the repair mechanism recognize the new strand (and thereby avoid replacing bases on the original template strand of DNA)?
|
The mismatch repair mechanism recognizes the template (and, therefore, the older strand) by its degree of methylation
-- older strands are methylated |
|
In single-stranded DNA repair, how is mismatch repair different from nucleotide excision and base excision repair?
|
Mismatch repair changes a mismatched nucleotide (using the degree of methylation to tell the new and old strands of DNA apart), whereas the other two types both repair damaged DNA (as opposed to mismatched DNA)
|
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Hereditary nonpolyposis colon cancer results from loss of what DNA repair mechanism?
|
DNA mismatch repair
|
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What is the name of the method of double-stranded DNA repair?
|
nonhomologous end joining
|
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A child presents to your office with dry skin and has a history of several skin cancers including melanoma; what is the likely diagnosis?
|
xeroderma pigmentosum- defect in nucleotide excision repair of thymidine dimers caused by UV light
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In what direction is DNA synthesized?
|
From 5' to 3'
|
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During DNA and RNA synthesis, what ion group is found at the 5′ end of the incoming nucleoside?
|
A triphosphate (two of the phosphates get cleaved off to produce the energy needed for the incoming nucleotide to bind to the previous nucleotide via its 3' Carbon on ribose)
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|
True or False: During RNA synthesis, the triphosphate bond provides the energy source for the formation of the new phosphodiester bond.
|
true
|
|
In what direction is RNA synthesized?
|
From 5' to 3'
|
|
True or False: During DNA synthesis, the triphosphate bond provides the energy source for the formation of the new phosphodiester bond.
|
true
|
|
In what direction does protein synthesis proceed?
|
N terminus to C terminus of the amino acids
|
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During DNA and RNA synthesis, what is the target of the incoming nucleotide?
|
The 3' hydroxyl of the nascent chain (carbon on the ribose)
|
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During protein synthesis amino acids are linked from _____ to _____.
|
N to C creating peptide bonds between adjacent amino acids
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What type of RNA is the largest?
|
mRNA (m = massive)
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What type of RNA is the most abundant?
|
rRNA (r = rampant)
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What type of RNA is the smallest?
|
tRNA (t = tiny)
|
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In prokaryotes, the initial AUG codes for what amino acid?
|
formyl Methionine (fMet)
|
|
What codon is the mRNA initiation codon?
|
AUG (or, rarely, GUG) (remember, AUG inAUGurates protein synthesis)
|
|
In eukaryotes, AUG codes for what amino acid?
|
methionine (Met)
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True or False: After completing translation, all eukaryotic proteins have a methionine at one end.
|
False; the initial methionine can be removed before translation is complete
|
|
During the process of eukaryotic protein synthesis, when can the initial methionine removed?
|
before translation is complete
|
|
List three stop codons.
|
UGA, UAA, UAG (remember U Go Away, U Are Away, and U Are Gone)
|
|
What is the name of the DNA site at which RNA polymerase and multiple other transcription factors bind?
|
promoter
|
|
What are the elements that make up the promoter region?
|
The promoter region is an AT-rich sequence with TATA and CAAT boxes
|
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Is a promoter upstream or downstream of its gene locus?
|
upstream
|
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In addition to RNA polymerase, what else binds to a promoter?
|
transcription factors
|
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What is the name for a DNA site where negative regulators (repressors) bind?
|
silencers
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|
What commonly results from a mutation within a promoter?
|
decreased transcription
|
|
What is the name for a stretch of DNA that alters gene expression by binding transcription factors?
|
enhancer
|
|
True or False: An enhancer that regulates expression can be located close to, far from, or within the intron of the gene that it regulates.
|
True
|
|
If an enhancer is located within the gene that it regulates, in what part of the gene is it typically found?
|
in an intron
|
|
What is the name for a negative regulator of gene expression?
|
repressor
|
|
In eukaryotes, what enzyme makes rRNA?
|
RNA polymerase I
|
|
True or False: In eukaryotes, RNA polymerases have a proofreading function.
|
false; RNA polymerases have no proofreading function in eukaryotes (DNA polyermase III has proofreading ability)
|
|
What poisonous protein, which inhibits RNA polymerase II, is found in death cap mushrooms?
|
alpha-amanitin
|
|
True or False: In eukaryotes, RNA polymerases can initiate chains.
|
true; no primer is needed as there is in DNA replication/synthesis
|
|
In eukaryotes, which RNA polymerase opens DNA at the promoter site?
|
RNA polymerase II
|
|
What are the sites at which RNA polymerase II opens DNA called?
|
promoter sites
|
|
In eukaryotes, what enzyme makes mRNA?
|
RNA polymerase II
|
|
In eukaryotes, what enzyme makes tRNA?
|
RNA polymerase III
|
|
In prokaryotes, what enzyme makes rRNA?
|
RNA polymerase -- there is only one type
|
|
In prokaryotes, what enzyme makes mRNA?
|
RNA polymerase -- there is only one type
|
|
In prokaryotes, what enzyme makes tRNA?
|
RNA polymerase-- there is only one type
|
|
Where does eukaryotic RNA processing occur?
|
in the nucleus-- the RNA must be fully processed-- capped, tailed and spliced before it can go out into the cytoplasm
|
|
List the three parts of eukaryotic RNA processing.
|
Capping on the 5' end with 7-methylguanosine, polyadenylation on the 3' end, and splicing out of the introns
|
|
What gets placed on the 5′ end during the process of capping?
|
7-methyl guanosine
|
|
After which event during protein synthesis does eukaryotic RNA processing occur?
|
transcription
|
|
On what end of mRNA does polyadenylation occur?
|
3' end (tail)
|
|
On what end of mRNA does capping occur?
|
5' end (head)
|
|
About how many As get added to the 3' end of mRNA during polyadenylation?
|
200
|
|
What gets added to the 3′ end during polyadenylation?
|
about 200 Adenines (As)
|
|
True or False: Initial RNA transcripts are called heterogeneous nuclear RNA.
|
true hnRNA = preRNA = before processing
|
|
True or False: Processed RNA can be transported out of the nucleus.
|
true
|
|
True or False: After RNA transcripts have been capped and tailed, they are called hnRNA.
|
False; this is mRNA, while the initial transcript is called hnRNA
|
|
What is the polyadenylation signal?
|
AAUAAA
|
|
True or False: Unprocessed RNA is never transported out of the nucleus.
|
true
|
|
True or False: Poly-A polymerase requires a template.
|
False; it just sees it polyadenylation signal and lays down a ton of As
|
|
True or False: The splicing of introns out of a primary mRNA transcript is done in a precise manner.
|
true
|
|
What gets spliced out of primary mRNA transcripts?
|
introns
|
|
What binds to a primary mRNA transcript and forms a spliceosome?
|
Small nuclear ribonucleoprotein particles (snRNPs) and other proteins
|
|
What is the shape of the intermediate that is formed during mRNA splicing?
|
lariat = lasso
|
|
What particles facilitate the splicing of mRNA?
|
small nuclear ribonuclear proteins (snRNPs)
|
|
What does a small nuclear ribonucleoprotein particle form after binding a 1° mRNA transcript?
|
splicosome
|
|
What is the name of the portions of a gene that contain the actual genetic information coding for the protein?
|
exon
|
|
True or False: The formation of mRNA from pre-mRNA involves splicing.
|
true
|
|
What is the name for the intervening noncoding segments of DNA within a gene?
|
introns
|
|
Different exons within a single gene can be combined by ____ _____ to make unique proteins in different tissues.
|
alternative splicing
|
|
True or False: The formation of mRNA from DNA involves transcription.
|
true
|
|
Beta-thalassemia occurs due to a mutation causing splicing defects in a process that combines different exons within a single gene. What is this process called?
|
alternative splicing
|
|
Other than aminoacyl-tRNA synthetase, what else is responsible for the accuracy of amino acid selection?
|
The binding of charged tRNA to the correct codon
|
|
How many nucleotides make up the structure of an average tRNA?
|
75-90-- it is the smallest type of RNA
|
|
True or False: If a tRNA gets mischarged and is not caught by aminoacyl-tRNA synthetase when it checks for errors, then the mischarged tRNA reads the usual codon.
|
True; it reads the usual codon but inserts a different amino acid
|
|
What shape is a tRNA?
|
cloverleaf form
|
|
What part of a tRNA lies opposite from its 3' aminoacyl end?
|
the anticodon end
|
|
What three-nucleotide sequence do all eukaryotic tRNAs have at their 3' ends?
|
CCA
|
|
Where in tRNA is there a high percentage of chemically modified bases?
|
at the 3' end
|
|
What is the energy source for tRNA?
|
ATP
|
|
Where on a tRNA does the amino acid bind?
|
the 3' end
|
|
During the process of charging tRNA, ATP gets converted to what?
|
AMP and pyrophosphate (PPi)
|
|
If a tRNA had a methionine bound to it, what would the sequence of the codon it binds read? (Give this in order from the 5' end to the 3' end.) What would its anticodon sequence read? (Give this in the same order.)
|
5' AUG 3' codon
5' CAU 3' anticodon it would look like this 3' UAC 5' tRNA anticodon 5' AUG 3' mRNA codon |
|
What enzyme charges tRNA by adding an amino acid to it?
|
aminoacyl tRNA synthetase
|
|
If a tRNA gets paired up and bound to an incorrectly matched amino acid and the error is caught when it gets checked, what happens to the amino tRNA-amino acid?
|
The bond between them gets hydrolyzed by the aminoacyl-tRNA synthetase enzyme
|
|
What are the substrates of the reaction that is catalyzed by aminoacyl-tRNA synthetase?
|
an uncharged tRNA, appropriate amino acid, and ATP
|
|
What does the reaction that is catalyzed by aminoacyl-tRNA synthetase yield?
|
A charged tRNA (a tRNA with the appropriate amino acid covalently bound), adenosine monophosphate, and pyrophosphate (AMP and PPi)
|
|
List the enzyme that scrutinizes the match between a tRNA and its amino acid.
|
aminoacyl tRNA synthetase (scrutinizes the aa before and after putting it on)
|
|
During protein synthesis, the energy to form a peptide bond comes directly from which bond?
|
From the aminoacyl-tRNA bond
|
|
At what points during amino acid attachment does aminoacyl-tRNA synthetase check the match between a tRNA and its amino acid?
|
Both before and after it binds the tRNA
|
|
What enzyme is responsible for hydrolyzing the bond between an incorrectly matched tRNA and amino acid?
|
aminoacyl tRNA synthetase
|
|
With what kind of chemical bond connects a tRNA attach to its amino acid?
|
covalent bond
|
|
How does tetracycline interfere with protein translation?
|
tetracycline binds to the 30S subunit of the ribosome preventing aminoacyl tRNA from binding
|
|
True or False: Accuracy in the first nucleotide position of an mRNA codon is required for proper protein synthesis.
|
true
|
|
True or False: Accuracy in the third nucleotide position of an mRNA codon is required for proper protein synthesis.
|
false; due to degeneracy of the genetic code, many times the 3rd base won't change the amino acid that is made
|
|
What is the third nucleotide position of an mRNA codon sometimes called?
|
the wobble position
|
|
True or False: Codons differing in the third nucleotide may code for the same tRNA/amino acid.
|
true
|
|
Different codons that code for the same tRNA/amino acid can differ in which position?
|
3rd/wobble position
|
|
_____ (Eukaryotes/prokaryotes) have ribosomes with 60S and 40S subunits.
|
Eukaryotes (Even numbers)
|
|
What are the sizes of the two subunits of the eukaryotic ribosome called?
|
40S and 60S subunits
|
|
When referring the "A site" of a ribosome, what does the "A" stand for?
|
aminoacyl-- where incoming tRNA-aa sits down
|
|
List the positions (sites) on a ribosome starting from the 5' end of a bound mRNA and going toward the 3' end.
|
E, P, A
|
|
At the start of protein synthesis, after the incoming amino acid binds to the A site, what happens to the bond between methionine and its tRNA?
|
it gets hydrolyzed
|
|
_____ (Eukaryotes/prokaryotes) have ribosomes with 50S and 30S subunits.
|
prokaryotes
|
|
At the start of protein synthesis, methionine sits in which site on the ribosome?
|
in the P site
|
|
At the start of protein synthesis, what process occurs at the same time as the hydrolysis of methionine's bond with its tRNA?
|
The formation of a peptidyl bond between methionine and the second amino acid in the polypeptide
|
|
When referring the "P site" of a ribosome, what does the "P" stand for?
|
peptidyl
|
|
What happens to the ribosome after the formation of a peptidyl bond?
|
it advances 3 bases in the 3' direction on the mRNA
|
|
During protein synthesis, the incoming amino acid binds to which site on the ribosome?
|
A site
|
|
True or False: Initiation factors (eIFs) for protein synthesis are activated by GTP hydrolysis.
|
true
|
|
In what direction relative to the mRNA does the ribosome shift after the formation of a peptidyl bond?
|
toward the 3' end
|
|
When the ribosome shifts after the formation of a peptidyl bond, in what position does the tRNA with the growing peptide chain end up?
|
the P site
|
|
What molecule provides the energy for the charging of tRNA?
|
ATP
|
|
What molecule provides the energy for the binding of tRNA to the ribosome/mRNA complex?
|
GTP
|
|
What molecule provides the energy for the translocation of the ribosome along the mRNA?
|
GTP
|
|
In protein synthesis, when are the initiation factors released?
|
When mRNA is bound to the ribosomal complex
|
|
In protein synthesis, what is the first step of elongation?
|
Aminoacyl-tRNA binds to the A site
|
|
In protein synthesis, what is the second step of elongation?
|
Peptidyltransferase adds the growing peptide to the amino acid at site A
|
|
In protein synthesis, what is the third step of elongation?
|
The ribosome advances three nucleotides in the 3' direction, thereby moving the tRNA with the growing peptide chain to the P site ?
|
|
In protein synthesis, what happens during termination?
|
The completed protein is released from the ribosome, which disassociates
|
|
When the ribosome shifts after the formation of a peptidyl bond, where is the uncharged tRNA found?
|
the E position
|
|
What is the order of the positions of the ribosome that the tRNA occupies during translation?
|
A, P, E (think of "going APE")
|
|
In protein synthesis, what is the role of initiation factors?
|
To assemble the 40S ribosomal subunit with the initiatior tRNA
|
|
In protein synthesis, what are the three steps of protein elongation?
|
(1) Aminoacyl-tRNA binds to the A site; (2) peptidyltransferase adds a peptide to the amino acid chain at site A; and (3) the ribosome advances three nucleotides in the 3′ direction, thereby moving the tRNA to the P site
|
|
In protein synthesis, the A site of the ribosome holds what?
|
The incoming Aminoacyl-tRNA
|
|
In protein synthesis, the P site of the ribosome holds what?
|
The growing Peptide chain
|
|
In protein synthesis, the E site of the ribosome holds what?
|
The Empty tRNA as it exits the ribosome
|
|
How do aminoglycosides interfere with protein synthesis?
|
They inhibit formation of the initiation complex, causing misreading of mRNA
|
|
During protein synthesis, the incoming amino acid binds to which site on the ribosome?
|
A site
|
|
True or False: Initiation factors (eIFs) for protein synthesis are activated by GTP hydrolysis.
|
true
|
|
In what direction relative to the mRNA does the ribosome shift after the formation of a peptidyl bond?
|
toward the 3' end
|
|
When the ribosome shifts after the formation of a peptidyl bond, in what position does the tRNA with the growing peptide chain end up?
|
the P site
|
|
What molecule provides the energy for the charging of tRNA?
|
ATP
|
|
What molecule provides the energy for the binding of tRNA to the ribosome/mRNA complex?
|
GTP
|
|
What molecule provides the energy for the translocation of the ribosome along the mRNA?
|
GTP
|
|
In protein synthesis, when are the initiation factors released?
|
When mRNA is bound to the ribosomal complex
|
|
In protein synthesis, what is the first step of elongation?
|
Aminoacyl-tRNA binds to the A site
|
|
In protein synthesis, what is the second step of elongation?
|
Peptidyltransferase adds the growing peptide to the amino acid at site A
|
|
In protein synthesis, what is the third step of elongation?
|
The ribosome advances three nucleotides in the 3' direction, thereby moving the tRNA with the growing peptide chain to the P site ?
|
|
In protein synthesis, what happens during termination?
|
The completed protein is released from the ribosome, which disassociates
|
|
When the ribosome shifts after the formation of a peptidyl bond, where is the uncharged tRNA found?
|
the E position
|
|
What is the order of the positions of the ribosome that the tRNA occupies during translation?
|
A, P, E (think of "going APE")
|
|
In protein synthesis, what is the role of initiation factors?
|
To assemble the 40S ribosomal subunit with the initiatior tRNA
|
|
In protein synthesis, what are the three steps of protein elongation?
|
(1) Aminoacyl-tRNA binds to the A site; (2) peptidyltransferase adds a peptide to the amino acid chain at site A; and (3) the ribosome advances three nucleotides in the 3′ direction, thereby moving the tRNA to the P site
|
|
In protein synthesis, the A site of the ribosome holds what?
|
The incoming Aminoacyl-tRNA
|
|
In protein synthesis, the P site of the ribosome holds what?
|
The growing Peptide chain
|
|
In protein synthesis, the E site of the ribosome holds what?
|
The Empty tRNA as it exits the ribosome
|
|
How do aminoglycosides interfere with protein synthesis?
|
They inhibit formation of the initiation complex, causing misreading of mRNA
|
|
What enzyme is affected by chloramphenicol?
|
chloramphenicol inhibits the 50S peptidyltransferase
|
|
Where do macrolides and clindamycin bind and what does this cause?
|
bind the 50S ribosome subunit and block translocation-- movement of the tRNA with the growing polypeptide chain to the P site
|
|
What is the result of clindamycin binding to the 50S subunit?
|
blocks translocation of tRNA
|
|
Why are antibiotics such as chloramphenicol, clindamycin, and macrolides selective for bacteria?
|
They affect the 50S subunit of the ribosome, which is found in prokaryotic cells
|
|
What conversion occurs with the breakage of 2 phosphoanhydride bonds from ATP?
|
ATP to AMP
|
|
True or False: The conversion of ATP to AMP occurs in tRNA aminoacylation.
|
true
|
|
Loading tRNA onto the ribosome is associated with the conversion of GTP to _____.
|
GDP
|
|
Translocation is associated with the conversion of _____ (ATP/GTP) to _____ (ADP/GDP).
|
GTP to GDP
|
|
What is the total energy expenditure required in the addition of a single amino acid to a protein in translation?
|
4 high energy phosphoanhydride bonds
|
|
Trimming is what kind of posttranslational protein modification?
|
The removal of N- or C- terminal propeptides from zymogens (inactive enzyme precursor) to generate mature proteins
|
|
Covalent alterations involve what kinds of posttranslational protein modifications?
|
Phosphorylation, glycosylation, and hydroxylation
|
|
"Proteosomal degradation" involves what kind of posttranslational protein modification?
|
The attachment of ubiquitin to defective proteins to tag them for breakdown
|
|
In protein synthesis, what is a zymogen?
|
An immature peptide in which the of N- or C-terminal propeptides have not been trimmed
|
|
Phosphorylation, glycosylation, and hydroxylation of a protein result in the formation of what kind of bond?
|
covalent
|
|
What form of covalent modification is commonly used to regulate enzymes?
|
phosphorylation
|
|
True or False: The feedback inhibition of enzymes is an example of allosteric regulation.
|
true
|
|
True or False: The action of steroid hormones is an example of the transcriptional regulation of enzymes.
|
true
|
|
List five ways that enzymes are regulated.
|
Enzyme concentration changes (synthesis and/or destruction), covalent modification, proteolytic modification, allosteric regulation, and transcriptional modification
|
|
What is a precursor enzyme that is regulated by proteolytic modification commonly called?
|
a zymogen
|
|
List the four main phases of mitosis in order.
|
Prophase--> metaphase--> anaphase--> telophase (PMAT)
|
|
True or False: Mitosis occurs during the S phase of the cell cycle.
|
False; mitosis occurs after G2 and before G1 in the cell cycle
|
|
During which phase of the cell cycle can a cell enter G0?
|
G1
|
|
When a cell comes out of G0, what phase of the cell cycle is it in?
|
G1
|
|
Which phase of the cell cycle is usually the shortest?
|
mitosis
|
|
Which phase of the cell cycle is shortened in rapidly dividing cells?
|
G1
|
|
Phase-specific _____ activate CDKs, which are constitutive and inactive.
|
cyclins
|
|
Phase-specific cyclins activate ____, which are constitutive and inactive.
|
CDKs (cyclin dependent kinases)
|
|
Permanent and stable cells are typically in which phase of the cell cycle?
|
G0
|
|
True or False: Mitosis occurs during the S phase of the cell cycle.
|
False; mitosis occurs after G2 and before G1 in the cell cycle
|
|
Checkpoints that control transitions between phases are regulated by which three factors?
|
Cyclins, CDKs, and tumor suppressor genes
|
|
True or False: Cyclin-CDK complexes must be both activated and inactivated for cell cycle to progress.
|
true
|
|
During which phase of the cell cycle can a cell enter G0?
|
G1
|
|
When a cell comes out of G0, what phase of the cell cycle is it in?
|
G1
|
|
Which phase of the cell cycle is usually the shortest?
|
mitosis
|
|
Which phase of the cell cycle is shortened in rapidly dividing cells?
|
G1
|
|
Phase-specific _____ activate CDKs, which are constitutive and inactive.
|
cyclins
|
|
Phase-specific cyclins activate ____, which are constitutive and inactive.
|
CDKs (cyclin dependent kinases)
|
|
Permanent and stable cells are typically in which phase of the cell cycle?
|
G0
|
|
Checkpoints that control transitions between phases are regulated by which three factors?
|
Cyclins, CDKs, and tumor suppressor genes
|
|
True or False: Cyclin-CDK complexes must be both activated and inactivated for cell cycle to progress.
|
true
|
|
Rb and p53 tumor suppressors normally inhibit which cell cycle phase?
|
G1--> S transition
|
|
_____ (Permanent/stable/labile) cells remain in G0 and regenerate from stem cells.
|
permanent
|
|
_____ (Permanent/stable/labile) cells enter G1 from G0 when stimulated.
|
stable
|
|
_____ (Permanent/stabl/labile) cells never go to G0 and divide rapidly with a short G1.
|
labile- always dividing
|
|
True or False: Stable cells regenerate from stem cells.
|
False; permanent cells regenerate from stem cells, stable cells are stimulated to enter G1 from g0
|
|
Neurons, skeletal and cardiac muscle, and RBCs are examples of _____ (permanent/stable/labile) cells.
|
permanent
|
|
Hepatocytes and lymphocytes are examples of _____ (permanent/stable/labile) cells .
|
stable
|
|
What type of cell never enters the G0 phase?
|
labile cells (skin, hair, gut epithelium, bone marrow)
|
|
Bone marrow, gut epithelium, skin, and hair follicles are examples of _____ (permanent/stable/labile) cells.
|
labile
|
|
Neurons, skeletal and cardiac muscle cells, and RBCs remain in which cell cycle phase?
|
G0
|
|
What happens to cell cycling when you have a mutation in a tumor suppressor such as Rb or p53?
|
There is unrestrained growth in the cell, and thus an increased likelihood to develop a malignancy
|
|
List the four main phases of the cell cycle in order.
|
Mitosis--> G1--> S--> G2
|
|
List the three components of interphase.
|
G1, S, G2
|
|
In what phases of the cell cycle does growth occur?
|
G1 and G2
|
|
What organelle is the site of the synthesis of secretory proteins?
|
rough endoplasmic reticulum
|
|
What are the main functions of the rough endoplasmic reticulum?
|
The synthesis of secretory (exported) proteins and the addition of N-linked oligosaccharides to proteins
|
|
Which type of sugar moiety is commonly added to proteins in the rough endoplasmic reticulum?
|
N-linked oligosaccharides
|
|
Give an example of a cell of the gastrointestinal tract that is rich in rough endoplasmic reticulum.
|
mucus secreting goblet cells
|
|
Give an example of a hematologic cell that is rich in rough endoplasmic reticulum.
|
plasma cells-- constantly making Ab proteins
|
|
What histologic finding is consistent with RER in neurons?
|
nissl bodies, which are the site of enzyme (e.g. Choline Acetyltransferase) and peptide neurotransmitters
|
|
Which organelle is not attached to any membrane and serves as the site of synthesis of cytosolic and organellar proteins?
|
free ribosomes
|
|
_____ (Free/attached) ribosomes synthesize cytosolic and organellar proteins, whereas _____ (free/attached) ribosomes synthesize secretory proteins.
|
free; attached
|
|
List two functions of the smooth endoplasmic reticulum.
|
detoxification and steroid synthesis
|
|
You are working a night shift in the ED when an infant comes in after getting into the medicine cabinet. Your resident turns to you and asks, "which hepatocyte organelle will likely detoxify these drugs?"
|
smooth endoplasmic reticulum
|
|
Give two examples of cells that are rich in smooth endoplasmic reticulum.
|
hepatocytes and steroid-hormone producing cells of the adrenal cortex
|
|
The Golgi apparatus functions as the distribution center for what?
|
Synthesized proteins and lipids
|
|
Proteins and lipids arrive at the Golgi apparatus from where?
|
endoplasmic reticulum
|
|
List three places to which the Golgi apparatus sends proteins and lipids.
|
The plasma membrane, lysosomes, and secretory vesicles
|
|
Clathrin is a protein that transports vesicles from the trans face of the Golgi apparatus to where?
|
To the lysosome/late endosome, or to the plasma membrane
|
|
What type of protein-bound saccharides get modified in the Golgi apparatus?
|
N-oligosaccharides
|
|
In patients with I-cell disease, the failure to add mannose-6-phosphate to proteins in the Golgi apparatus leads to what deficit?
|
There is no signal that targets the lysosomal protein to the lysosome
|
|
N-oligosaccharides bound to which amino acid get modified in the Golgi apparatus?
|
asparagine
|
|
List four common findings among patients with I-cell disease.
|
coarse facial features, clouded corneas, restricted joint movement, and elevated levels of lysosomal enzymes in the plasma-- may lead to death in early childhood
|
|
What should you inform the parents of a child who has been diagnosed with I-cell disease about the prognosis?
|
Unfortunately, this disease is often fatal in childhood
|
|
What type of saccharides get added to proteins in the Golgi apparatus?
|
O-linked oligosaccharides
|
|
COPII is associated with _____ (retrograde/anterograde) movement from the _____ _____ _____ to the cis-Golgi.
|
anterograde; rough endoplasmic reticulum
|
|
O-oligosaccharides get added to which two amino acid residues in the Golgi apparatus?
|
serine and threonine
|
|
True or False: Proteoglycans get assembled from their component core proteins in the Golgi apparatus.
|
true
|
|
By what process are sugars in proteoglycans modified in the Golgi apparatus?
|
sulfation
|
|
In addition to the sugars on proteoglycans, what else gets sulfated in the Golgi apparatus?
|
selected tyrosine residues on proteins
|
|
What gets added to specific lysosomal proteins in the Golgi apparatus?
|
mannose-6-phosphate--targeting them for lysosomes
|
|
What is the function of the addition of mannose-6-phosphate to certain proteins in the Golgi apparatus?
|
It targets them to the lysosome
|
|
What disease results from the failure of the addition of mannose-6-phosphate to lysosomal proteins?
|
I cell disease
|
|
COPI is associated with _____ (retrograde/anterograde) movement from the Golgi apparatus to the _____ _____.
|
retrograde; endoplasmic reticulum
|
|
What is the basic pathophysiologic defect in patients with I-cell disease?
|
The failure of the addition of mannose-6-phosphate to lysosomal proteins
|
|
What is the fate of lysosomal proteins in patients with I-cell disease?
|
The proteins get secreted outside of the cell instead of being targeted to the lysosome
|
|
True or False: COPI, COPII and clathrin mediate vesicular trafficking in the Golgi apparatus.
|
true
|
|
Clathrin is a protein that transports vesicles via receptor-mediated endocytosis from the plasma membrane to which organelle?
|
endosome
|
|
What is the name of the process by which clathrin transports vesicles from outside the cell to inside the cell through fusion of the two lipid-based membranes?
|
receptor mediated endocytosis
|
|
_____ (COPI/COPII) mediates retrograde transport of substances from the golgi apparatus to endoplasmic reticulum. whereas _____ (COPI/COPII) mediates anterograde transport of substances from the rough endoplasmic reticulum to cis-Golgi apparatus,
|
COPI; COPII
|
|
Is kinesin involved in transport from the cell body to the axon (anterograde transport) or from the axon to the cell body (retrograde transport)?
|
cell body --> axon (anterograde)
|
|
Microtubules are formed from what two protein building blocks?
|
α-Tubulin and β-tubulin
|
|
What syndrome results from a microtubule polymerization defect that leads to impaired lysosomal emptying and poor phagocytosis?
|
Chediak Higashi syndrome
|
|
Microtubules are found in the _____ _____, which is a structure that is important in the process of mitosis.
|
mitotic spindle
|
|
True or False: Microtubule filaments grow rapidly but collapse quickly.
|
false; they grow SLOWLY but collapse rapidly
|
|
What high-energy phosphate molecule is bound to each tubulin dimer?
|
GTP (guanosine triphosphate)
|
|
Microtubules are found in what two structures that are involved in cell motility?
|
cilia and flagella
|
|
Are microtubules involved in fast or slow transport along the neuronal axons?
|
slow transport along neuronal axons
|
|
What is the underlying defect in symptoms of Chédiak-Higashi syndrome: pyogenic infections, partial albinism, and peripheral neuropathy?
|
A microtubule polymerization defect; this disrupts phagocytosis, the secretion of melanin, and axonal transport in neurons
|
|
Is dynein involved in transport from the cell body to the axon (anterograde transport) or from the axon to the cell body (retrograde transport)?
|
axon--> cell body (retrograde transport)
|
|
How many guanosine triphosphate molecules are bound to each tubulin dimer?
|
2 GTP per dimer
|
|
What drug that is used to treat gout acts on microtubules?
|
Colchicine
|
|
What anticancer drugs block the polymerization of microtubules?
|
vincristine and vinblastine
|
|
What anticancer drug used to treat breast cancers stabilizes microtubules?
|
paclitaxel (taxol)
|
|
What antifungal agent targets microtubules?
|
griseofulvin
|
|
What antihelminthic drugs target microtubules?
|
Mebendazole and Thiabendazole
|
|
What ATPase is responsible for retrograde transport on the microtubule?
|
dynein
|
|
What ATPase is responsible for anterograde transport on the microtubule?
|
kinesin
|
|
How are cilia structurally composed?
|
9 Microtubule doublets around 2 central microtubules
|
|
What syndrome results from a defect in the dynein arm of cilia?
|
kartagener's syndrome
|
|
What is the mechanism by which cilia bend?
|
Differential sliding of the peripheral microtubule doublets
|
|
What protein causes the movement of the cilia?
|
axonemal dynein ATPase that causes the bending of the cilium
|
|
Which diagnosis should you consider in a male with infertility, bronchiectasis and recurrent sinusitis?
|
Kartegener's syndrome
|
|
True or False: Kartagener's syndrome causes only male infertility.
|
False; Kartagener's syndrome causes infertility in both sexes
|
|
A 22-year-old female presents with a 10-day history of productive cough with yellow-green sputum. Subsequent CXR reveals dextrocardia. What is the most likely diagnosis involving these two findings?
|
Kartagener's syndrome
|
|
A patient with infertility, bronchiectasis, and chronic sinus infections likely has what genetic disease that is caused by nonmotile cilia?
|
kartagener's syndrome
|
|
What is the underlying cellular malfunction that leads to Kartagener's syndrome?
|
Immotile cilia as a result of a dynein arm defect
|
|
Immotile cilia as a result of a dynein arm defect cause what symptoms?
|
male and female infertility, bronciectasis, repeated sinus infections (it is associated with situs inversus)- kartagener's syndrome
|
|
Microvilli and adherens junctions are composed of which two cytoskeletal elements?
|
actin and myosin
|
|
Which two cytoskeletal elements are necessary for muscle contraction and cytokinesis?
|
actin and myosin
|
|
Cilia, flagella, mitotic spindles, neurons and centrioles are all composed of which cytoskeletal element?
|
microtubules
|
|
Vimentin, desmin, cytokeratin, glial fibrillary acid proteins, and neurofilaments are all different types of which cytoskeletal element?
|
intermediate filaments
|
|
Approximately what percent of the plasma membrane is composed of cholesterol?
|
50%
|
|
Approximately what percent of the plasma membrane is composed of phospholipids?
|
50%
|
|
What is the effect on melting temperature if the content of cholesterol in the plasma membrane is increased?
|
increased melting temperature
|
|
What is the effect on melting temperature if the content of long-chain saturated fatty acids in the plasma membrane is decreased?
|
decreased melting temperature
|
|
Does increasing the content of cholesterol have the same or the opposite effect on melting temperature as compared with the increasing amount of long saturated fatty acids in the plasma membrane?
|
It has the same effect; both increase the melting temperature
|
|
True or False: The plasma membrane is a symmetric fluid bilayer that is composed of phospholipids, sphingolipids, glycolipids, cholesterol, and proteins.
|
False; the plasma membrane is asymmetric
|
|
What is the effect on the plasma membrane of increased long saturated fatty acid content?
|
increased melting temperature and decreased fluidity
|
|
What is the effect on the plasma membrane of increased cholesterol?
|
increased melting temperature and decreased fluidity
|
|
Vimentin stains identify which type of cells?
|
connective tissue
|
|
Desmin stains identify which type of cells?
|
muscle
|
|
Cytokeratin stains identify which type of cells?
|
epithelial cells
|
|
Neurofilament stains identify which type of cells?
|
neurons
|
|
Glial fibrillary acid protein (GFAP) stains identify which type of cells?
|
neuroglia
|
|
The ATP binding site of the Na+-K+-ATPase is on which side of the plasma membrane?
|
cytosol (inside)
|
|
Na+-K+-ATPase moves _____ (how many) Na+ ions out in exchange for _____ (how many) K+ ions in.
|
3 Na+ out; 2 K+ in (against their concentration gradients)
|
|
During the movement of Na+ across the plasma membrane, is the Na+-K+-ATPase phosphorylated or dephosphorylated?
|
phosphorylated?
|
|
What effect does the inhibition of the Na+-;K+-ATPase by digoxin or digitoxin have on cardiac contractility?
|
increased cardiac contractility because calcium is stuck inside the cell since the Na+/Ca2+ gradient cannot be established
|
|
True or False: Digoxin and digitoxin inhibit the Na+-K+-ATPase, increasing cardiac contractility.
|
true
|
|
Where does ouabain bind to the Na+-K+-ATPase?
|
At the K+ binding site
|
|
How does inhibition of Na+-K+ exchange result in increased cardiac contractility?
|
There is indirect inhibition of Na+-Ca2+ exchange, which results in increased intracellular Ca2+ concentration
(sodium is not pumped out of the cell, therefore there is no gradient established for sodium to be pumped back in, while Ca2+ goes out) |
|
What is the most abundant type of collagen?
|
type I collagen (it is #1)
|
|
What type of collagen is found in teeth?
|
dentin- type I collagen
|
|
What type of collagen is found in bone?
|
type ONE collagen in bONE
|
|
True or False: Collagen is the most abundant protein in the human body.
|
true
|
|
True or False: A defect in collagen synthesis would result in a weakened, well-organized extracellular matrix.
|
False; collagen plays an important role in the strength and organization of the extracellular matrix
|
|
What type of collagen is found in dentin?
|
type I
|
|
What type of collagen is found in the uterus?
|
type III collagen
|
|
What type of collagen predominates in fetal tissue?
|
type III collagen
|
|
What type of collagen is found in the cornea?
|
type I (cOrNEa) = ONE
|
|
What type of collagen is found in the basal lamina?
|
type IV collagen
|
|
What type of collagen is found in the basement membrane?
|
type IV collagen
|
|
During wound healing, type ____ collagen is laid down first as part of granulation tissue. Then, type ____ collagen is produced as part of late wound healing.
|
III; I
|
|
What type of collagen is found in the skin and fascia?
|
type I
|
|
What two types of collagen are found in the skin?
|
Types I and III
|
|
What two types of collagen are found in the eye?
|
Type I in cornea, type II in vitreous body
|
|
What type of collagen is found in the vitreous body?
|
type II
|
|
What type of collagen is found in the nucleus pulposus?
|
type II
|
|
What type of collagen is found in hyaline cartilage?
|
type II (carTWOlage)
|
|
What type of collagen is found in blood vessels?
|
type III
|
|
What is another name for type III collagen?
|
reticulin (reticular = net-like)
|
|
What type of collagen is found on the articular surface of joints?
|
type II
|
|
True or False: Once collagen is translated, there is very little further modification.
|
false; collagen is extensively modified
|
|
A triple helix composed of three collagen α chains that has not yet been cleaved is referred to as what?
|
procollagen
|
|
Where does collagen synthesis occur in the cell?
|
in the rough endoplasmic reticulum
|
|
True or False: The majority of a collagen molecule is composed of a repeating tripeptide that is composed of glycine, proline, and either hydroxyproline or hydroxylysine.
|
true
|
|
True or False: Essentially every third amino acid in a collagen α chain is a glycine residue.
|
Gly-X-Y where X and y are either proline, hydroxyproline, or hydroylysine,
|
|
Which vitamin is required for the hydroxylation of proline and lysine in collagen?
|
Vitamin C-- if none--> scurvy
|
|
The conversion of preprocollagen to procollagen requires what process?
|
glycosylation
|
|
A single-collagen α chain during collagen synthesis is referred to as what?
|
preprocollagen
|
|
Where in the cell are collagen α chains hydroxylated?
|
in the endoplasmic reticulum
|
|
What form of collagen is exocytosed from the cell into the extracellular space?
|
procollagen
|
|
An -OH group is added to _____ and _____ after translation of the collagen α chain.
|
proline; lysine
|
|
What is the name of the enzyme that cleaves the terminal regions of procollagen?
|
procollagen peptidase
|
|
Where in the cell are preprocollagen molecules glycosylated?
|
in the endoplasmic reticulum
|
|
British sailors in the 17th century come to you due to an inability to hydroxylate proline and lysine residues for collagen synthesis. What disease do they have, and why do you prescribe limes?
|
They have developed scurvy, and the limes will supply them with the vitamin C they are deficient in during their long voyage (and earn them the nickname, "limeys")
|
|
A triple helix that is composed of three collagen α chains with the terminal regions cleaved off is referred to as what?
|
tropocollagen (once terminal regions cleaved-->tropocollagen)
|
|
Is tropocollagen formed intracellularly or extracellularly?
|
extracellularly
|
|
What is the name of the enzyme that covalently cross-links lysine residues to hydroxylysine residues?
|
lysyl oxidase
|
|
Many staggered tropocollagen molecules with covalent lysine-hydroxylysine cross-links are referred to as _____ _____.
|
collagen fibrils
|
|
Is lysyl oxidase found intracellularly or extracellularly?
|
Extracellularly
|
|
Does the formation of tropocollagen from the cleavage of procollagen increase or decrease its solubility?
|
Decreases; tropocollagen is insoluble.
|
|
What cell type is responsible for collagen synthesis?
|
fibroblasts
|
|
What disease results in an inability to form procollagen from pro alpha chains?
|
osteogenesis imperfecta
|
|
Ehlers-Danlos syndrome is a defect of what process?
|
collagen synthesis (type III is most frequently affected)
|
|
True or False: There are 6 types of Ehlers-Danlos syndrome.
|
true
|
|
Ehlers-Danlos syndrome is associated with what defects of the vasculature of the brain?
|
berry aneurysms
|
|
True or False: All 6 types of Ehlers-Danlos syndrome are transmitted through an autosomal recessive inheritance pattern.
|
False; Ehlers-Danlos syndrome shows variable inheritance, depending on the type- may be autosomal dominant
|
|
A patient presents with hyperextensible skin, easy bruising, and hypermobile joints. What is the most likely diagnosis?
|
Ehlers Danlos syndrome
|
|
What type of collagen is most frequently affected in Ehlers-Danlos syndrome?
|
type III collagen (reticulin)
|
|
Why might patients with Ehlers-Danlos syndrome have an increased risk of organ rupture?
|
Poor type III collagen synthesis results in weak blood vessels and reticular fibers in organs
|
|
What type of inheritance does osteogenesis imperfecta show?
|
autosomal dominant
|
|
A baby is born with multiple fractures and hearing loss. What finding is expected during the ophthalmologic examination?
|
blue sclera
|
|
True or False: The incidence of osteogenesis imperfecta is roughly 1:1,000,000
|
False; the incidence is 1:10,000
|
|
Osteogenesis imperfecta is a defect of what type of synthesis?
|
collagen synthesis (mostly type I collagen)
|
|
How is the development of blue sclerae in osteogenesis imperfecta similar to the reason these infants have brittle bones?
|
Both symptoms are due to a loss of normal functioning type I collagen. The blue sclerae result from decreased connective tissue over the choroid in the eye, while multiple fractures are from weak and decreased collagen in the bone matrix
|
|
True or False: Osteogenesis imperfecta and Ehlers-Danlos syndrome result from defects in the synthesis of the same molecule.
|
true; collagen
|
|
Which type of osteogenesis imperfecta is fatal in utero?
|
type II
|
|
True or False: Osteogenesis imperfecta is also known as brittle bone disease.
|
true
|
|
Broken bones that result from osteogenesis imperfecta may be confused with what?
|
child abuse
|
|
The dental imperfections seen in osteogenesis imperfecta is due to lack of _____ in the teeth?
|
dentin (made my type I collagen)
|
|
A young woman with blue sclerae also has hearing loss. What is the hearing loss a result of?
|
abnormal ossicles (bones of the middle ear)
|
|
What is the typical inheritance pattern of Alport's syndrome?
|
X-linked recessive
|
|
What type of collagen is disrupted in Alport's syndrome?
|
type IV collagen
|
|
Would you expect the onset of symptoms in Alport's syndrome to be rapid or progressive?
|
progressive- the nephritis and deafness are progressive
|
|
True or False: Alport's syndrome is the result of a single point mutation in the collagen IV gene.
|
False; Alport's syndrome is due to a variety of gene defects
|
|
You are seeing a man who has progressive deafness and renal failure. The other males in his family show the same symptoms; what is the likely diagnosis?
|
Alport's syndrome, which is typified by progressive nephritis and deafness
|
|
What organ (other than the kidneys and the ears) can be affected in Alport's syndrome?
|
This disease may result in ocular lesions
|
|
What is the relationship between Alport's syndrome and Goodpasture's syndrome?
|
Both are diseases of type IV collagen (Alport's is genetic; Goodpasture's is autoimmune)
|
|
What role does fibrillin (the protein that is found to be defective in patients with Marfan's syndrome) play?
|
it acts a scaffold for tropoelastin
|
|
Where is the structural role of type IV collagen?
|
Type IV collagen is an important part of the basement membrane in the kidneys, eyes, and ears
|
|
What is a stretchy protein found within lungs, large arteries, elastic ligaments, vocal cords, ligamenta flava (which connect the vertebrae)?
|
elastin
|
|
α1-Antitrypsin inhibits which enzyme?
|
elastase which degrades elastin
|
|
Excess elastase activity can result in what lung disorder?
|
emphysema: α1-antitrypsin inhibits elastase, which degrades elastin; therefore, a lack of α1-antitrypsin can leads to the loss of elastin in the lungs, thereby resulting in emphysema
|
|
True or False: Elastin has both a relaxed form and a stretched form.
|
true
|
|
Elastin is rich in which two amino acids?
|
proline and glycine
|
|
Marfan's syndrome is caused by a defect in what protein?
|
fibrillin
|
|
Proline and glycine can be found in elastin in the (glycosylated / nonglycosylated) form.
|
nonglycosylated
|
|
Is polymerase chain reaction used to amplify the number of copies of DNA fragments or of RNA fragments?
|
DNA fragments
|
|
How is the size of a DNA fragment determined from an agarose gel?
|
A DNA ladder of known lengths is run alongside the PCR fragments
|
|
How is DNA separated into two strands during polymerase chain reaction?
|
it is denatured into two strands by heating
|
|
In polymerase chain reaction, premade _____ are used to anneal to specific DNA sequences that will then be amplified.
|
primers
|
|
What enzyme is used in polymerase chain reaction to amplify DNA?
|
heat-stable DNA polymerase
|
|
True of False: The DNA polymerase used in polymerase chain reaction has to be heat stable to withstand the denaturation process that is used to separate DNA strands.
|
true
|
|
True or False: One round of DNA denaturation followed by primer binding and the replication by DNA polymerase is enough to yield a large number of copies of a desired DNA fragment.
|
False; many rounds of denaturation and replication are required to yield a large number of DNA fragments
|
|
Identify the technique: DNA is denatured by heat into two strands. DNA primers anneal to complementary sites on a strand of DNA. Heat-stable DNA polymerase replicates the segment of DNA between two primers.
|
polymerase chain reaction (PCR)
|
|
Following PCR, how can products be separated and analyzed?
|
Agarose gel electrophoresis
|
|
Which would travel further on an agarose gel: a 10-kD or an 100-kD DNA fragment?
|
10 kD fragment- smaller molecules travel farther
|
|
Does a Western blot detect specific sequences of DNA, RNA, or protein?
|
protein
|
|
Identify the technique: Sample protein is separated via gel electrophoresis and transferred to a filter. Labeled antibody is used to bind the protein of interest.
|
Western Blot
|
|
What blot technique detects specific sequences of DNA?
|
Southern Blot
|
|
How does the mnemonic "SNoW DRoP" help one remember which type of blot is used to detect DNA sequences, RNA sequences, or proteins?
|
SNoW DRoP
Southern DNA Northern RNA Western Protein |
|
Does a Southern blot detect specific sequences of DNA, RNA, or protein?
|
DNA
|
|
Identify the technique: DNA is run on an electrophoresis gel and transferred to a filter. The DNA on the filter is denatured and exposed to a labeled DNA probe. The double-stranded DNA is visualized when the filter is exposed to film.
|
Southern Blot
|
|
What blot technique detects specific sequences of RNA?
|
noRthern blot
|
|
Does a Northern blot detect specific sequences of DNA, RNA, or protein?
|
RNA
|
|
Identify the technique: RNA is run on an electrophoresis gel and transferred to a filter. The RNA on the filter is exposed to a labeled DNA probe. The hybrid DNA-RNA molecule is visualized when the filter is exposed to film.
|
Northern blot
|
|
What blot technique detects specific proteins?
|
Western blot
|
|
Which assay would allow you to detect single nucleotide polymorphisms (SNPs)?
|
microarrays
|
|
How can a microarray profile gene expression levels?
|
The microarray scanner can detect relative amounts of complementary binding to probes on a chip
|
|
Identify the technique: Thousands of nucleic acid sequences are arranged in grids on glass or silicon. DNA or RNA probes are hybridized to the chip, and a scanner detects the relative amounts of complementary binding.
|
microarrays
|
|
True or False: In the microarray biology technique, DNA or RNA probes are hybridized to the chip.
|
True; either DNA or RNA probes may be used- chip contains grid of a bunch of DNA sequences
|
|
What information would an ELISA using a test antigen coupled to a color-generating enzyme give you?
|
It would tell you whether a certain antibody is present in the patient's blood
|
|
True or False: Enzyme-linked immunosorbent assay tests antigen-antibody reactivity.
|
true
|
|
What information would an ELISA using a test antibody coupled to a color-generating enzyme give you?
|
It would tell you whether a certain antigen is present in the patient's blood
|
|
True or False: Enzyme-linked immunosorbent assay is only used to detect whether an antigen is present in a patient's blood. It cannot be used to test for the presence of an antibody.
|
False; it can be used to test for the presence of an antibody in a patient's blood-- there are two different techniques-one using labeled antigen to find antibody and the other using labeled anitbody to find antigen
|
|
Identify the technique: A test antigen that is labeled with a color-generating enzyme can be used to determine the presence of a specific antibody. If the antibody is present, the solution will have an intense color reaction.
|
Enzyme-Linked ImmunoSorbent Assay (ELISA)
|
|
True or False: The sensitivity and specificity of the enzyme-linked immunosorbent assay approaches 100%.
|
true; however, false-negative and false-positive results may still occur-- which is why when you get an initial HIV ELISA screening test that is positive you do a western blot to confirm the result
|
|
What is the advantage of a FISH analysis over a karyotype?
|
The FISH analysis allows researchers to identify anomalies at a molecular level, including deletions that are too small to see on a karyotype
|
|
What allows FISH analysis to detect deletions too small to visualize on karyotype?
|
The small DNA or RNA probe used in FISH analysis allows you to illuminate a difference that is too small to otherwise see under a microscope, as in karyotyping
|
|
What laboratory technique is represented with the acronym FISH?
|
Fluorescence In Situ Hybridization
|
|
What type of probe is used in fluorescent in situ hybridization?
|
A fluorescent probe binds to a site of genetic interest
|
|
What does fluorescent in situ hybridization allow researchers to do?
|
Directly visualize the location of a certain protein or gene on a molecular level through a fluorescent probe that binds to a site of interest-- can see translocations, deletions, etc
|
|
What does DNA cloning produce?
|
A recombinant DNA molecule that is self-perpetuating
|
|
In cloning, DNA fragments are inserted into bacterial plasmids containing genes coding for what?
|
antibiotic resistance
|
|
In cloning, what is the significance of inserting DNA to be replicated into plasmids also containing antibiotic-resistance genes and then growing the bacteria on media containing the antibiotic that bacteria is resistant to?
|
This technique selects for replication of the plasmid containing genes for antibiotic resistance AND the DNA of interest
|
|
What is the type of DNA sequence in which the sequence on 1 strand reads the same in the same direction on the complementary strand?
|
palindromic sequence (this is where restriction endonucleases cleave yielding sticky ends)
|
|
In cloning, restriction enzymes cleave DNA at _____ base pair palindromic sequences, allowing for ______ of a fragment into a plasmid.
|
4-6; insertion
|
|
In cloning, tissue mRNA produced from DNA inserted into a bacterial plasmid is isolated and exposed to which enzyme, forming a cDNA library?
|
reverse transcriptase
|
|
In cloning, tissue mRNA is isolated and exposed to reverse transcriptase, forming a _____library.
|
cDNA = complementary DNA
|
|
In cloning, _______ is isolated and exposed to reverse transcriptase, forming a cDNA library.
|
mRNA
|
|
Which type of enzymes cleave DNA at 4- to 6-bp palindromic sequences in cloning?
|
restriction enzymes/endonucleases
|
|
What distinguishes cDNA from most nuclear DNA?
|
it lacks introns since it was produced from processed mRNA
|
|
acute (adj.)
|
sharp, severe
|
|
In which laboratory technique do dideoxynucleotides halt DNA polymerization at each base, generating sequences of various lengths that encompass the entire original sequence so that the terminated fragments are electrophoresed and the original sequence can be deduced?
|
Sanger DNA sequencing
|
|
In Sanger DNA sequencing, dideoxynucleotides halt DNA polymerization at each base, generating sequences of various lengths. These terminated fragments then undergo which procedure?
|
gel electrophoresis
|
|
True or False: In Sanger DNA sequencing, electrophoresis of terminated fragments with subsequent sequencing of fragments allows revealing of the original DNA sequence.
|
true
|
|
What property of Sanger DNA sequencing is crucial to the ability to determine a DNA sequence using electrophoresis?
|
A dideoxyribonucleotide must interrupt the sequence at every base in the sequence
|
|
There are two transgenic strategies in mice: ______ insertion of a gene and _______ insertion or deletion of a gene.
|
random/constitutive; targeted/conditional
|
|
Targeted insertion or deletion of a gene into the genome of a mouse occurs through which step?
|
homologous recombination with mouse gene
|
|
How does an antibiotic-controlled promoter allow you to study genes in which the deletion of that particular gene leads to death of the embryo?
|
The gene can be "turned off" following the embryo stage using the antibiotic
|
|
_____ (Knock-out/Knock-in) refers to the removal of a gene from a host genome and _____ (knock-out/knock-in) refers to the insertion of a gene into a host genome.
|
knock-out; knock-in
|
|
In RNA inhibition, the degradation of target mRNA inhibits which process?
|
translation; thus reducing gene expression
|
|
True or False: Genes can be manipulated at specific developmental points using an inducible Cre-lox system with an antibiotic-controlled promoter.
|
true
|
|
In which laboratory technique do dideoxynucleotides halt DNA polymerization at each base, generating sequences of various lengths that encompass the entire original sequence so that the terminated fragments are electrophoresed and the original sequence can be deduced?
|
Sanger DNA sequencing
|
|
In Sanger DNA sequencing, dideoxynucleotides halt DNA polymerization at each base, generating sequences of various lengths. These terminated fragments then undergo which procedure?
|
gel electrophoresis
|
|
True or False: In Sanger DNA sequencing, electrophoresis of terminated fragments with subsequent sequencing of fragments allows revealing of the original DNA sequence.
|
true
|
|
What property of Sanger DNA sequencing is crucial to the ability to determine a DNA sequence using electrophoresis?
|
A dideoxyribonucleotide must interrupt the sequence at every base in the sequence
|
|
There are two transgenic strategies in mice: ______ insertion of a gene and _______ insertion or deletion of a gene.
|
random/constitutive; targeted/conditional
|
|
Targeted insertion or deletion of a gene into the genome of a mouse occurs through which step?
|
homologous recombination with mouse gene
|
|
How does an antibiotic-controlled promoter allow you to study genes in which the deletion of that particular gene leads to death of the embryo?
|
The gene can be "turned off" following the embryo stage using the antibiotic
|
|
_____ (Knock-out/Knock-in) refers to the removal of a gene from a host genome and _____ (knock-out/knock-in) refers to the insertion of a gene into a host genome.
|
knock-out; knock-in
|
|
In RNA inhibition, the degradation of target mRNA inhibits which process?
|
translation; thus reducing gene expression
|
|
True or False: Genes can be manipulated at specific developmental points using an inducible Cre-lox system with an antibiotic-controlled promoter.
|
true
|
|
Regarding model systems, genes can be manipulated at specific development points using an inducible Cre-lox system with what type of promoter?
|
anitbiotic-controlled promoter
|
|
What is the mechanism in which double-stranded RNA is synthesized complementary to the mRNA sequence of interest and transfected into human cells, where the dsRNA then separates and promotes degradation of the target mRNA knocking down gene expression?
|
RNA inhibition
|
|
In RNA inhibition, dsRNA is synthesized then transfected into human cells where it separates and promotes the degradation of which molecule?
|
mRNA
|
|
Regarding model systems, antibiotic-controlled promoters are used to manipulate gene expression at different _____ points in the growth of the mouse host.
|
developmental -- so you can see the effects of the gene expression at various stages
|
|
What phase of mitosis are the chromosomes in when performing a karyotype?
|
metaphase-- where homologous pairs are aligned
|
|
What process compares chromosomes based on morphology, size, arm-length ratio, and banding pattern?
|
karyotyping
|
|
What is the diagnostic value of a karyotype?
|
It can diagnose chromosomal imbalances
|
|
In a karyotype, chromosomes are paired and arranged in what pattern?
|
They are arranged by chromosome number
|
|
Name three types of chromosome imbalances that can be seen on a karyotype.
|
Autosomal trisomies (aneuploides--monosomies can be seen too--if they were compatible with life), microdeletions, and sex chromosome disorders
|
|
What tissue can be used to perform a karyotype on a fetus?
|
placenta and amniotic fluid
|
|
What are four tissues that can be used for chromosomal analysis?
|
blood, bone marrow, amniotic fluid or placental tissue
|
|
The _____ _____ of a genetic disease indicates that the nature and severity of the phenotype varies from one individual to another with the same disease.
|
variable expression (e.g. patients with marfan's may have the same genotype but may have more or less severe phenotypic expression)
|
|
If a genetic disease shows _____ _____, it means that not all individuals with the mutant genotype will show the complete mutant phenotype.
|
incomplete penetrance
|
|
A genetic disease that shows _____ has a different phenotype depending on whether the mutation is inherited from the mother or from the father.
|
imprinting
|
|
True or False: Linkage disequilibrium can be measured in families as well as in larger populations.
|
False; linkage disequilibrium can be measured only in larger populations.
|
|
What word describes the situation in which cells in the body have a different genetic makeup?
|
mosaicism
|
|
What is the name of the phenomenon whereby a genetic disease has an earlier onset or worsening severity in each subsequent generation?
|
anticipation
|
|
What word describes the phenomenon of a single gene having more than one effect on an individual's phenotype?
|
pleitropy
|
|
True or False: Prader-Willi syndrome is an example of genetic imprinting.
|
true- it occurs when the gene is deleted from normally active Paternal allele, if the gene is deleted from the normally active Maternal allele, angelMan's syndrome with result
|
|
True or False: Lyonization (ie, the random inactivation of one X chromosome in females) is an example of mosaicism.
|
true
|
|
A patient has inherited a mutation in a tumor suppressor gene. Mutation of the remaining (previously normal) copy of the tumor suppressor gene represents a loss of _____, which may lead to the development of cancer.
|
Heterozygosity; the patient was previously a heterozygote for the lost tumor suppressor gene
|
|
True or False: Oncogenes, in a manner similar to tumor-suppressor genes, must have a deletion/mutation in the complementary allele before cancer develops.
|
False; the mutation of a single oncogene can produce cancer
|
|
A genetic disease that shows _____ _____ will have mutations at different loci that produce the same phenotype.
|
locus heterogeneity
|
|
True or False: Angelman's syndrome is an example of genetic imprinting.
|
true; if the gene is deleted from normally active Maternal allele, angelMan's syndrome with result, if deleted from normally active Paternal allele, Prader-Willi syndrome will result
|
|
True or False: Albinism is an example of a genetic disease that demonstrates locus heterogeneity.
|
true- more than one gene at more than one locus has been implicated in this phenotype
|
|
Give an example of disease that shows genetic anticipation.
|
Huntington's disease-- the severity of the disease is worse and/or age of onset is earlier in succeeding generations
|
|
What term describes the presence of both normal and mutated mitochondrial DNA (mtDNA), resulting in variable expression in mitochondrial inherited diseases?
|
heteroplasmy
|
|
A nonfunctional altered protein that also prevents the normal gene product from functioning is called what?
|
dominant negative mutation
|
|
Name the genetic phenomenon that occurs when the offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent.
|
uniparental disomy
|
|
The tendency for certain alleles to be inherited together more often than is expected by chance is called what?
|
linkage disequilibrium
|
|
What equation describes the allele prevalence in a population that is in Hardy-Weinberg equilibrium?
|
p + q = 1
|
|
True or False: The Hardy-Weinberg law assumes that there are no mutations at the locus being studied.
|
true
|
|
What equation describes the disease prevalence in a population that is in Hardy-Weinberg equilibrium?
|
p2 + 2pq + q2 = 1 where q2 is the prevalence of an autosomal recessive disease, and 2pq is the prevalence of heterozygosity or carriers in an autosomal recessive disease
|
|
What is the heterozygote prevalence in a population that is in Hardy-Weinberg equilibrium?
|
2pq
|
|
True or False: The Hardy-Weinberg law assumes that there is no selection for any of the genotypes at the locus being studied.
|
true- there must be no environmental advantage to having on genotype, or it would be selected for
|
|
In Hardy-Weinberg population genetics, what do "p" and "q" represent?
|
allele frequencies
|
|
True or False: The Hardy-Weinberg law assumes that mating is completely random.
|
true-- no incest either!
|
|
True or False: The Hardy-Weinberg law assumes that there is no migration into or out of the population being considered.
|
true
|
|
True or False: The Hardy-Weinberg law shows that advantageous alleles are more frequently selected during mating and thus appear more frequently in the population.
|
False; it assumes that there is no selection of one genotype over another and that mating is random
|
|
True or False: The Hardy-Weinberg law shows that mutations can either be advantageous or disadvantageous or that they can have no effect on an organism's survival.
|
False; it assumes that there are no mutations at the locus being studied
|
|
The Hardy-Weinberg law shows that the prevalence of an X-linked recessive disease in males is represented by _____ (q/q2) and in females is represented by _____ (q/q2).
|
q in males; q2 in females
|
|
The prevalence of which type of genetic disease is indicated by males = q and females = q2 using Hardy-Weinberg genetics?
|
x-linked recessive diseases
|
|
How is Prader-Willi syndrome inherited?
|
loss/deactivation of normally active Paternal allele on chromosome 15
|
|
In genetics, what does the term imprinting refer to?
|
the deletion of an active allele leads to disease because only one allele is active at the locus (due to methylation of the imprinted or inactive allele) -- this means that a different phenotype can result depending on whether there is deletion of maternal or paternal allele
|
|
How is Angelman's syndrome inherited?
|
It is inherited via the deactivation of normally active maternal allele on chromosome 15
|
|
In genetics, how is an imprinted disease inherited?
|
A disease in which imprinting plays a role is inherited in an autosomal fashion, but the disease can vary depending on whether the paternal or maternal allele is affected
|
|
Where is the gene located in Prader-Willi syndrome? In Angelman's syndrome?
|
Both syndromes are due to inactivation or deletion of genes on chromosome 15
|
|
What are the signs of Prader-Willi syndrome?
|
hyperphagia, obesity, hypotonia, hypogonadism, and mental retardation
|
|
What are the signs of Angelman's syndrome?
|
"happy puppet syndrome", mental retardation, seizures, inappropriate laughter, ataxia
|
|
Angelman's syndrome and Prader-Willi syndrome are examples of what kind of genetic inheritance?
|
imprinting
|
|
True or False: Imprinting can also occur as a result of uniparental disomy.
|
true
|
|
In Leber's hereditary optic neuropathy, vision loss is _____ (central/peripheral).
|
central
|
|
Autosomal-dominant patterns of inheritance are often found in diseases caused by defects in _____ genes.
|
structural
|
|
True or False: A mother with an X-linked dominant disease may pass the disease only to her daughters.
|
False; both her sons and her daughters may be affected (50% of passing along the allele to either her sons or daughters)
|
|
True or False: Patients with autosomal-dominant disorders often present clinically after puberty.
|
true
|
|
What is the pattern of inheritance of hypophosphatemic rickets?
|
x-linked dominant
|
|
What is the mode of inheritance if a disease is present in many generations and affects both males and females in roughly equal proportions?
|
autosomal dominant
|
|
What is the mode of inheritance in a family in which a disease is transmitted only through the mother and all children (both boys and girls) are affected?
|
mitochondrial inheritance
|
|
Autosomal-recessive patterns of inheritance are often found in diseases caused by defects in _____.
|
enzymes
|
|
True or False: A mother may pass a disease with a mitochondrial pattern of inheritance to both her sons and her daughters.
|
true since all mitochondrial DNA is passed through the mother
|
|
What is the mode of inheritance if a gene is present in a single generation and 25% of the offspring from the same two parents have the disease?
|
autosomal recessive
|
|
What is the pattern of inheritance of Leber's hereditary optic neuropathy?
|
mitochondrial inheritance
|
|
True or False: Patients with autosomal-recessive disorders often present clinically during childhood.
|
true because autosomal recessive diseases are often more severe than autosomal dominant ones
|
|
What is the pattern of inheritance of mitochondrial myopathies?
|
mitochondrial
|
|
What would you expect to see on urinalysis in a patient with hypophosphatemic rickets?
|
You would expect an increased urine phosphate level since there is proximal tubule phosphate loss
|
|
Variable expression of mitochondrial inheritance in a population is due to _____ (heteroplasmy/uniparental disomy).
|
heteroplasmy
|
|
True or False: Hypophosphatemic rickets can be treated by vitamin D supplementation.
|
false; it is caused excess secretion of phosphate, not deficiency of vitamin D-- hence this disease is also called vitamin D resistant rickets
|
|
What is the mechanism of phosphate wasting in hypophosphatemic rickets?
|
There is increased phosphate wasting at the proximal renal tubule
|
|
Which cells are affected in Leber's hereditary optic neuropathy?
|
the degeneration of retinal ganglion cells and their axons
|
|
In general, are autosomal-dominant or autosomal-recessive disorders more severe?
|
autosomal recessive
|
|
True or False: A patient who has had a progressive loss of visual acuity with a positive family history has a good probability of having Leber's hereditary optic neuropathy.
|
False; the vision loss in Leber's hereditary optic neuropathy is acute
|
|
What is the mode of inheritance in a family in which 50% of sons are affected and there is no male-to-male transmission?
|
x-linked recessive
|
|
What percentage of sons of a carrier mother are expected to inherit an X-linked recessive disease?
|
50%
|
|
True or False: Females are never affected by X-linked recessive diseases.
|
False; heterozygous females may be affected by some X-linked recessive diseases
|
|
True or False: X-linked recessive diseases are commonly more severe in males than in females.
|
true
|
|
Are X-linked dominant diseases transmitted through the mother only, through the father only, or through both parents?
|
both parents
|
|
True or False: A mother with an X-linked dominant disease may pass the disease to either her sons or her daughters.
|
true
|
|
True or False: A father with an X-linked dominant disease will pass the disease to all of his daughters but none of his sons.
|
true
|
|
What is the mode of inheritance of achondroplasia?
|
autosomal dominant
|
|
A mother with achondroplasia is pregnant; what is the likelihood that her child will also have the disease?
|
50%
|
|
Achondroplasia is the result of a defect in the ____ receptor.
|
fibroblast growth factor receptor 3 (FGF3)
|
|
A patient has dwarfism with short limbs but a normally sized head and trunk. What is the most likely diagnosis?
|
achondroplasia
|
|
What is the paternal age more likely to pass on the trait for achondroplasia: 20, 30, or 40?
|
40 achondroplasia is associated with advanced paternal age
|
|
True or False: Achondroplasia results from a defect in cell signaling.
|
True; there is no signaling from the missing fibroblast growth factor 3 receptor
|
|
What is the mode of inheritance of adult polycystic kidney disease?
|
autosomal dominant
|
|
True or False: Adult polycystic kidney disease is associated with mitral valve prolapse.
|
true
|
|
A patient with known APKD undergoes a right renal biopsy in the hospital that shows multiple large cysts; what would a biopsy of the left kidney show?
|
It would also demonstrate the large cysts typical of APKD; this disease is always bilateral
|
|
A patient has hematuria, hypertension, and progressive renal failure. His kidneys are both massively dilated as a result of multiple large cysts. What is the most likely diagnosis?
|
ADPKD
|
|
True or False: Adult polycystic kidney disease is associated with primary adrenocortical insufficiency.
|
False; but is associated with polycystic liver disease, berry aneurysm, and mitral valve prolapse
|
|
Ninety percent of cases of adult polycystic kidney disease are associated with a mutation in what gene?
|
APKD1
|
|
How many parents must carry the gene that causes the infantile form of polycystic kidney disease?
|
Both parents must carry the gene to pass the trait on to the child since this disease is autosomal recessive
|
|
The gene APKD1 is located on which chromosome?
|
Chromosome 16 (remember: 16 letters in 7 "polycystic kidney")
|
|
Adult polycystic kidney disease is inherited in an autosomal-_____ (dominant/recessive) pattern, whereas juvenile polycystic kidney disease is associated with an autosomal-_____ (dominant/recessive) pattern.
|
dominant; recessive
|
|
True or False: Adult polycystic kidney disease is associated with dilated cardiomyopathy.
|
False; but is associated with polycystic liver disease, berry aneurysm, and mitral valve prolapse
|
|
True or False: Adult polycystic kidney disease is associated with berry aneurysms.
|
true
|
|
What is the mode of inheritance of familial adenomatous polyposis?
|
autosomal dominant
|
|
A patient has adenomatous polyps that carpet his colon. What is the most likely diagnosis?
|
familial adenomatous polyposis
|
|
True or False: A patient with familial adenomatous polyposis has no increased risk of cancer.
|
False; adenomatous polyps will progress to cancer unless they are resected
|
|
Achondroplasia is the result of a defect in the ____ receptor.
|
fibroblast growth factor receptor 3 (FGF3)
|
|
The defect that leads to familial adenomatous polyposis is found on chromosome ____.
|
5 (remember: 5 letters in "polyp")
|
|
A patient has dwarfism with short limbs but a normally sized head and trunk. What is the most likely diagnosis?
|
achondroplasia
|
|
The defect that leads to familial adenomatous polyposis is found in the ____ gene.
|
APC (A Polypy Colon or A Polyp Carpet)
|
|
What is the paternal age more likely to pass on the trait for achondroplasia: 20, 30, or 40?
|
40 achondroplasia is associated with advanced paternal age
|
|
True or False: Achondroplasia results from a defect in cell signaling.
|
True; there is no signaling from the missing fibroblast growth factor 3 receptor
|
|
What is the mode of inheritance of adult polycystic kidney disease?
|
autosomal dominant
|
|
True or False: Adult polycystic kidney disease is associated with mitral valve prolapse.
|
true
|
|
A patient with known APKD undergoes a right renal biopsy in the hospital that shows multiple large cysts; what would a biopsy of the left kidney show?
|
It would also demonstrate the large cysts typical of APKD; this disease is always bilateral
|
|
A patient has hematuria, hypertension, and progressive renal failure. His kidneys are both massively dilated as a result of multiple large cysts. What is the most likely diagnosis?
|
ADPKD
|
|
True or False: Adult polycystic kidney disease is associated with primary adrenocortical insufficiency.
|
False; but is associated with polycystic liver disease, berry aneurysm, and mitral valve prolapse
|
|
Ninety percent of cases of adult polycystic kidney disease are associated with a mutation in what gene?
|
APKD1
|
|
A patient has dwarfism with short limbs but a normally sized head and trunk. What is the most likely diagnosis?
|
achondroplasia
|
|
What is the paternal age more likely to pass on the trait for achondroplasia: 20, 30, or 40?
|
40; achondroplasia is associated with advanced paternal age
|
|
True or False: Achondroplasia results from a defect in cell signaling.
|
True; there is no signaling from the missing fibroblast growth factor 3 receptor
|
|
What is the mode of inheritance of adult polycystic kidney disease?
|
autosomal dominant
|
|
True or False: Adult polycystic kidney disease is associated with mitral valve prolapse.
|
true
|
|
A patient with known APKD undergoes a right renal biopsy in the hospital that shows multiple large cysts; what would a biopsy of the left kidney show?
|
It would also demonstrate the large cysts typical of APKD; this disease is ALWAYS BILATERAL
|
|
A patient has hematuria, hypertension, and progressive renal failure. His kidneys are both massively dilated as a result of multiple large cysts. What is the most likely diagnosis?
|
ADPKD
|
|
True or False: Adult polycystic kidney disease is associated with primary adrenocortical insufficiency.
|
False; but is associated with polycystic liver disease, berry aneurysm, and mitral valve prolapse
|
|
Ninety percent of cases of adult polycystic kidney disease are associated with a mutation in what gene?
|
APKD1 (adult polycystic kidney disease)
|
|
How many parents must carry the gene that causes the infantile form of polycystic kidney disease?
|
Both parents must carry the gene to pass the trait on to the child since this disease is autosomal recessive
|
|
The gene APKD1 is located on which chromosome?
|
Chromosome 16 (remember: 16 letters in "polycystic kidney")
|
|
Adult polycystic kidney disease is inherited in an autosomal-_____ (dominant/recessive) pattern, whereas juvenile polycystic kidney disease is associated with an autosomal-_____ (dominant/recessive) pattern.
|
dominant; recessive
|
|
True or False: Adult polycystic kidney disease is associated with dilated cardiomyopathy.
|
False; but is associated with polycystic liver disease, berry aneurysm, and mitral valve prolapse
|
|
True or False: Adult polycystic kidney disease is associated with berry aneurysms.
|
true
|
|
What is the mode of inheritance of familial adenomatous polyposis?
|
autosomal dominant
|
|
A patient has adenomatous polyps that carpet his colon. What is the most likely diagnosis?
|
familial adenomatous polyposis
|
|
True or False: A patient with familial adenomatous polyposis has no increased risk of cancer.
|
False; adenomatous polyps will 100% of the time progress to cancer unless they are resected
|
|
The defect that leads to familial adenomatous polyposis is found on chromosome ____.
|
5 (remember: 5 letters in "polyp")
|
|
The defect that leads to familial adenomatous polyposis is found in the ____ gene.
|
APC (A Polypy Colon, A Polyp Carpet)
|
|
A patient with FAP asks you if he might not eventually develop colon cancer; what is your reply?
|
Patients with FAP will all progress to colon cancer unless the colon is resected
|
|
What is the mode of inheritance of familial hypercholesterolemia?
|
autosomal dominant
|
|
Familial hypercholesterolemia is the result of a defect in what type of receptor?
|
LDL receptor
|
|
In patients with familial hypercholesterolemia, heterozygotes can be expected to have a cholesterol level around ____ mg/dL, and homozygotes can be expected to have a cholesterol level around ____ mg/dL.
|
300; 700
|
|
A middle-aged woman had a myocardial infarction 20 years ago, and has tendon xanthomas on her Achilles tendon. What is the most likely diagnosis?
|
familial hypercholesterolemia
|
|
A child is born to a parent homozygous for Osler-Weber-Rendu syndrome; what are the odds that the child will also have the disease?
|
100%; this is an autosomal dominant disease
|
|
What is another name for Osler-Weber-Rendu syndrome?
|
Hereditary hemorrhagic telangiectasia
|
|
What is the tissue involved in Osler-Weber-Rendu syndrome?
|
this is a disorder of the blood vessels
|
|
Why is recurrent epistaxis a common finding in Osler-Weber-Rendu syndrome?
|
Malformed blood vessels in the nose can break and cause frequent nosebleeds
|
|
A patient has multiple telangiectasias, skin discolorations, and notes recurrent epistaxis; what other physical finding might be expected?
|
arteriovenous malformations (AVMs)- this is the constellation of symptoms/findings seen with hereditary hemorrhagic telangectasia/ Osler Weber Rendu
|
|
What is the mode of inheritance of hereditary spherocytosis?
|
autosomal dominant
|
|
A patient has hemolytic anemia, increased mean corpuscular hemoglobin concentration, and spheroid erythrocytes. What is the most likely diagnosis?
|
hereditary spherocytosis
|
|
True or False: RBCs in patients with hereditary spherocytosis have increased concentrations of hemoglobin.
|
true (inc MCHC) red blood cells have less surface area and volume and hence more concentrated hemoglobin
|
|
True or False: Hereditary spherocytosis is associated with abnormally shaped RBCs.
|
True; instead of a biconcave disk, RBCs are shaped like spheres
|
|
A patient with known hereditary spherocytosis comes in complaining of fatigue, shortness of breath, and feels pale; what is a possible diagnosis and its mechanism?
|
This patient appears to be anemic, likely due to increased hemolysis of spheroid erythrocytes
|
|
In refractory cases, how can you cure hereditary spherocytosis?
|
splenectomy- the spleen is removing the malformed RBCs
|
|
What is the mode of inheritance of Huntington's disease?
|
autosomal dominant
|
|
A patient develops depression, progressive dementia, and choreiform movements. What is the most likely diagnosis, and how old are they likely to be?
|
Huntington's disease; symptoms usually begin between 20 and 50 years of age
|
|
You are performing an autopsy on a man who had Huntington's disease; what would you find on inspection of the brain?
|
Huntington's disease is associated with atrophy of the caudate leading to "bat wing ventricles"
|
|
Which psychiatric diagnoses are commonly associated with Huntington's disease?
|
depression and progressive dementia
|
|
Huntington's disease is associated with _____ movements.
|
choreiform -- thus it can also be called Huntington's chorea (purposeless, dancelike movements)
|
|
True or False: Symptoms of Huntington's disease generally manifest between the ages of 20 and 50 years.
|
true
|
|
The defect that leads to Huntington's disease is found on chromosome ____.
|
4; (remember: Hunting 4 food)
|
|
What would a genetic analysis of a patient with Huntington's disease demonstrate on chromosome 4?
|
Trinucleotide repeats of (CAG)n in the Huntington gene
|
|
Patients with Huntington's disease have decreased levels of what in their central nervous system?
|
γ-aminobutyric acid (GABA) and acetylcholine (ACh)
|
|
True or False: Patients with Huntington's disease have increased levels of γ-aminobutyric acid and acetylcholine in the central nervous system.
|
False; Huntington's disease is associated with decreased levels of these substances
|
|
True or False: Symptoms of Huntington's disease generally manifest between the ages 10 and 20 years, before most people have had children.
|
False; symptoms of Huntington's disease manifest between the ages of 20 and 50 years
|
|
What is the mode of inheritance of Marfan's syndrome?
|
autosomal dominant
|
|
Marfan's syndrome is the result of a mutation in the _____ gene that leads to connective tissue disorders.
|
fibrillin
|
|
True or False: Marfan's syndrome is associated with a tall habitus and long, tapering fingers and toes.
|
true
|
|
True or False: Marfan's syndrome is associated with arachnodactyly.
|
True; arachnodactyly describes long, tapering fingers and toes
|
|
True or False: Marfan's syndrome is associated with hyperflexible joints.
|
true- as is Ehler's danlos- an inherited collagen defect
|
|
True or False: Marfan's syndrome is associated with cystic medial necrosis of the aorta.
|
true- this can lead to aortic incompetence and dissecting aortic aneurysms
|
|
True or False: Marfan's syndrome is associated with aortic incompetence.
|
true- because of cystic medial necrosis of the aorta
|
|
True or False: Marfan's syndrome is associated with dissecting aortic aneurysms.
|
true- because of cystic medial necrosis of the aorta
|
|
True or False: Marfan's syndrome is associated with subluxation of the lenses.
|
true
|
|
True or False: Marfan's syndrome is associated with skeletal abnormalities such as arachnodactyly and hyperflexible joints but no abnormalities of the cardiovascular system.
|
False; patients with Marfan's syndrome can have cystic medial necrosis of the aorta leading to aortic insufficiency and dissecting aortic aneurysms
they also have floppy mitral valves |
|
A patient with Marfan's asks you whether, given his elastic joint flexibility, this disorder is from a mutation in the elastin gene. How do you reply?
|
The disorder is actually a mutation in the fibrillin gene, which in turn affects the organization of elastin in various tissues
|
|
What is the inheritance pattern of multiple endocrine neoplasias?
|
autosomal dominant
|
|
How many different syndromes are considered "multiple endocrine neoplasias"?
|
Three, collectively known as MEN I, MEN II, and MEN III (or MEN I, and MEN2A and MEN2B)
|
|
True or False: MEN syndromes may involve cancers originating in the adrenal cortex?
|
False; MEN syndromes cause familial tumors of endocrine glands, and include cancers in the adrenal medulla but not the adrenal cortex
|
|
Name 5 endocrine organs that develop tumors in the multiple endocrine neoplasia syndromes
|
pancreas, pituitary, parathyroid, adrenal medulla, and thyroid
|
|
True or False: MEN I is associated with a mutation in the ret gene.
|
False; MEN II/MEN2A and MEN III/MEN2B are associated with ret mutations
|
|
A tall male patient enters the ED with the combination of a dissecting ascending aorta and acute mitral valve prolapse; what disorder might explain these findings?
|
marfan's syndrome- associated with cystic medial necrosis of the aorta which may lead to a dissection, as well as a floppy mitral valve prone to prolapse
|
|
What is the mode of inheritance of neurofibromatosis type 1?
|
autosomal dominant- this is also called von Recklinghausen's disease
|
|
What is the mode of inheritance of von Recklinghausen's disease?
|
autosomal dominant- this is also called NF1
|
|
What is another name for neurofibromatosis type 1?
|
von Recklinghausen's disease
|
|
Which chromosome would you want to study if a patient comes in with signs and symptoms suggestive of von Recklinghausen's disease?
|
The defect is a mutation on the long arm of chromosome 17 (remember: there are 17 letters in "von Recklinghausen")
|
|
A patient has café-au-lait spots, Lisch nodules, scoliosis, neural tumors, and pheochromocytoma. What is the most likely diagnosis?
|
Neurofibromatosis type 1 (von Recklinghausen's disease)
|
|
True or False: Neurofibromatosis type 1 is associated with café-au-lait spots.
|
true
|
|
True or False: Neurofibromatosis type 1 is associated with neural tumors.
|
true
|
|
True or False: Neurofibromatosis type 1 is associated with Lisch nodules.
|
true
|
|
What is another term for the pigmented iris hamartomas associated with neurofibromatosis?
|
lisch nodules
|
|
True or False: Neurofibromatosis type 1 is associated with skeletal disorders such as scoliosis.
|
true
|
|
True or False: Neurofibromatosis type 1 is associated with pheochromocytoma.
|
true
|
|
True or False: Neurofibromatosis type 1 is associated with ash leaf spots.
|
False; it is associated with café-au-lait spots (tuberous sclerosis is associated with "ash leaf spots")
|
|
True or False: Neurofibromatosis type 1 is associated with skin and eye abnormalities but no skeletal abnormalities.
|
False; neurofibromatosis type 1 may be associated with skeletal abnormalities such as scoliosis
|
|
True or False: Neurofibromatosis is not associated with any increased risk of cancer.
|
False; neurofibromatosis type 1 is associated with neural tumors, optic pathway gliomas, pheochromocytoma, and increased tumor susceptibility
|
|
What is the mode of inheritance for neurofibromatosis type 2?
|
autosomal dominant
|
|
A patient has bilateral acoustic neuroma, optic pathway gliomas, and juvenile cataracts. What is the most likely diagnosis?
|
neurofibromatosis type 2 (NF2)
|
|
A patient presents with bilateral acoustic neuromas; her underlying disease is most likely _____ (neurofibromatosis type 1/neurofibromatosis type 2)?
|
Neurofibromatosis type 2 is commonly associated with bilateral acoustic neuromas
|
|
True or False: Neurofibromatosis type 2 is associated with juvenile cataracts.
|
true
|
|
True or False: Neurofibromatosis type 2 is associated with skin findings that are similar to those of neurofibromatosis type 1.
|
False; neurofibromatosis type 2 is not associated with abnormal skin findings
|
|
True or False: Neurofibromatosis type 2 is not associated with tumors.
|
False; neurofibromatosis type 2 is associated with bilateral acoustic neuromas
|
|
Neurofibromatosis type 2 is a result of a mutation in the gene _____ found on chromosome _____.
|
NF2, 22
|
|
What is the mode of inheritance of tuberous sclerosis?
|
autosomal dominant
|
|
A patient has adenoma sebaceum on his face, ash leaf spots on his trunk, mental retardation, and seizures. What the most likely diagnosis?
|
Tuberous sclerosis
|
|
Where would you find adenoma sebaceum lesions on a patient with tuberous sclerosis?
|
These lesions are hamartomatous angiofibromas that are found on the face
|
|
True or False: Tuberous sclerosis is associated with cortical and retinal hamartomas.
|
true
|
|
What renal findings might distinguish a patient with tuberous sclerosis from a patient with APKD?
|
While both will have renal cysts, tuberous sclerosis is associated with renal angiomyolipomas
|
|
What is a cardiac manifestation of tuberous sclerosis?
|
Cardiac rhabdomyoma
|
|
True or False: Tuberous sclerosis is not associated with any abnormal skin findings.
|
False; tuberous sclerosis is associated with ash leaf spots and adenoma sebaceum
|
|
True or False: Patients with tuberous sclerosis have no central nervous system involvement.
|
False; tuberous sclerosis is associated with mental retardation and seizures
|
|
Compared to the general population, patients with tuberous sclerosis have an increased incidence of which brain tumor?
|
astrocytomas
|
|
True or False: All patients who inherit the gene in tuberous sclerosis will display very similar signs and symptoms.
|
False; although autosomal dominant, this disease has incomplete penetrance and a variable presentation
|
|
What is the mode of inheritance of von Hippel-Lindau disease?
|
autosomal dominant
|
|
A patient has hemangiomas of the retina and cerebellum, as well as bilateral renal cell carcinoma. What is the most likely diagnosis?
|
von Hippel Lindau disease
|
|
True or False: An individual with von Hippel-Lindau disease may develop benign vascular tumors in the retina.
|
true; this describes retinal hemangiomas
|
|
A patient has hematuria and flank pain; further work-up shows multiple bilateral renal cell carcinomas and makes you suspect which disease?
|
von hippel lindau disease: About half of the individuals with von Hippel-Lindau disease will develop multiple bilateral renal cell carcinomas
|
|
True or False: Von Hippel-Lindau disease is associated with pheochromocytomas.
|
False; Von Hippel-Lindau disease is associated with bilateral renal cell carcinoma
|
|
True or False: Von Hippel-Lindau disease is associated with acoustic neuromas.
|
False; von Hippel-Lindaudisease is associated with hemangioblastomas of the retina, the cerebellum, and the medulla
|
|
True or False: Patients with von Hippel-Lindau disease do not have an increased risk of cancer.
|
False; von Hippel-Lindau disease is associated with an increased risk of cancer
|
|
Von Hippel-Lindau disease is a result of the deletion of the _____ gene, which functions as a _____ (tumor suppressor/oncogene).
|
VHL; tumor suppressor
|
|
The defect that leads to von Hippel-Lindau disease is found on chromosome _____.
|
3 (remember: Von Hippel-Lindau = 3 words for chromosome 3)
|
|
What is the mode of inheritance of cystic fibrosis?
|
autosomal recessive
|
|
What is the mode of inheritance of albinism?
|
autosomal recessive
|
|
What is the mode of inheritance of α1 antitrypsin deficiency?
|
autosomal recessive
|
|
What is the mode of inheritance of phenylketonuria?
|
autosomal recessive
|
|
What is the mode of inheritance of the thalassemias?
|
autosomal recessive
|
|
What is the mode of inheritance of sickle cell disease?
|
autosomal recessive
|
|
What is the mode of inheritance of the glycogen storage diseases?
|
autosomal recessive
|
|
What is the mode of inheritance of most mucopolysaccharidoses?
|
autosomal recessive (Hunter's syndrome is x-linked recessive)
|
|
Most mucopolysaccharidoses are inherited in a(n) _____-_____ pattern, except for _____ _____.
|
autosomal recessive; hunter's syndrome
|
|
Most sphingolipidoses are inherited in a(n) _____-_____ pattern, except for _____ _____.
|
autosomal recessive; Fabry's disease
|
|
What is the mode of inheritance of ARPKD?
|
Autosomal recessive; this was formerly known as infantile polycystic kidney disease
|
|
What is the mode of inheritance of hemochromatosis?
|
autosomal recessive
|
|
What is the pattern of inheritance of cystic fibrosis?
|
autosomal recessive
|
|
Cystic fibrosis results from a defect in which gene?
|
CFTR
|
|
Cystic fibrosis is caused by a defect on chromosome ____.
|
7
|
|
Cystic fibrosis is the result of a defective channel for what ion?
|
Chloride (Cl-)
|
|
Patients with cystic fibrosis characteristically have mucus plugs that disturb the function of which three organs?
|
lungs, pancreas, and liver
|
|
Which two pathogens are the most likely to cause recurrent pulmonary infections in a patient with cystic fibrosis?
|
pseudomonas and staph aureus
|
|
True or False: Recurrent lung infection, emphysema, and bronchiectasis are characteristic lung manifestations in patients with cystic fibrosis.
|
False; patients with cystic fibrosis tend to have chronic bronchitis rather than emphysema
|
|
What is the mechanism of pancreatic insufficiency in cystic fibrosis patients?
|
Production of thick mucus forms plugs which block the pancreatic ducts
|
|
An infant with failure to thrive also had meconium ileus as a newborn. What is the most likely diagnosis?
|
cystic fibrosis
|
|
High concentrations of chloride ions in the sweat are diagnostic for what disease?
|
cystic fibrosis
|
|
A patient is in the hospital for recurrent pulmonary infection with Pseudomonas. She has a history of steatorrhea and had a meconium ileus as an infant. What is the likely diagnosis?
|
cystic fibrosis
|
|
A male patient with cystic fibrosis asks you whether he will be able to have children; what is your response?
|
Unfortunately, males with cystic fibrosis are infertile due to bilateral absence of the vas deferens
|
|
Are patients with cystic fibrosis at risk for deficiencies of water-soluble vitamins or fat-soluble vitamins?
|
fat soluble vitamins
|
|
A patient with cystic fibrosis is at increased risk for the deficiency of what four vitamins?
|
D, A, K, E all of which are fat soluble
|
|
What is the most common lethal genetic disease among Caucasians?
|
cystic fibrosis
|
|
Treatment with what drug helps to loosen mucous plugs in patients with cystic fibrosis?
|
n-acetylcysteine (mucomist)
|
|
How does N-acetylcysteine free up mucous plugs?
|
It cleaves the disulfide bonds that connect mucous glycoproteins
|
|
In cystic fibrosis, the CFTR channel _____ (actively/passively) secretes chloride in the lungs and gastrointestinal tract and _____ (actively/passively) reabsorbs chloride from sweat.
|
actively; actively
|
|
What is the pattern of inheritance of fragile X syndrome?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Fragile X)
|
|
What is the pattern of inheritance of Duchenne's muscular dystrophy?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Duchene)
|
|
What is the pattern of inheritance of hemophilia A?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Hemophilia A)
|
|
What is the pattern of inheritance of hemophilia B?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Hemophilia B)
|
|
What is the pattern of inheritance of Fabry's disease?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Fabry's)
|
|
What is the pattern of inheritance of glucose-6-phosphate dehydrogenase deficiency?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Glucose-6-phosphate dehydrogenase)
|
|
What is the pattern of inheritance of Hunter's syndrome?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Hunter's)
|
|
What is the pattern of inheritance of ocular albinism?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Ocular albinism)
|
|
What is the pattern of inheritance of Lesch-Nyhan syndrome?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Lesch-Nyhan)
|
|
What is the pattern of inheritance of Bruton's agammaglobulinemia?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Bruton's agammaglobulinemia)
|
|
What is the pattern of inheritance of Wiskott-Aldrich syndrome?
|
X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Wiskott-Aldrich)
|
|
True or False: Glucose-6-phosphate dehydrogenase deficiency has the same pattern of inheritance as sickle cell anemia.
|
False; glucose-6-phosphate dehydrogenase deficiency has X-linked recessive inheritance, whereas sickle cell anemia involves autosomal-recessive inheritance
|
|
True or False:: Hunter's syndrome has the same pattern of inheritance as Fabry's disease.
|
True; both have an X-linked recessive inheritance pattern
|
|
True or False: Hunter's syndrome has the same pattern of inheritance as Hurler's syndrome.
|
False; Hunter's syndrome has X-linked recessive inheritance, whereas Hurler's syndrome has autosomal-recessive inheritance
|
|
True or False: Female carriers of X-linked recessive disorders are commonly affected by the disorders that they are carrying.
|
False; they are rarely affected because of random inactivation of X chromosomes in each cell
|
|
Why are female carriers of X-linked recessive disorders rarely affected?
|
There is random inactivation of X chromosomes in each cell, a process known as lyonization
|
|
Duchenne's muscular dystrophy is caused by a deletion of what gene?
|
The dystrophin gene (remember: Duchenne's = Deleted Dystrophin)
|
|
Is the loss of the dystrophin gene in Duchenne's muscular dystrophy the result of frame-shift mutation, unbalanced chromosomal translocation, or improper protein folding?
|
Frame-shift mutation
|
|
True or False: Patients with Duchenne's muscular dystrophy have accelerated muscle breakdown.
|
true
|
|
True or False: Patients with Duchenne's muscular dystrophy tend to present before the age of 5 years with muscle weakness.
|
true
|
|
In what muscle group does weakness normally begin in patients with Duchenne's muscular dystrophy?
|
pelvic girdle muscles
|
|
True or False: A classic presentation of Duchenne's muscular dystrophy is pelvic girdle weakness that progresses inferiorly.
|
False; the weakness tends to first progress superiorly
|
|
A 4-year-old boy needs to use his upper extremities to push against his legs in order to stand up. What is the name of this maneuver?
|
gower's manuever- the action is necessary due to the weakness of the proximal muscles
|
|
Gower's maneuver is associated with what disease?
|
Duchenne's muscular dystrophy
|
|
A 4-year-old boy with Duchenne's muscular dystrophy has hypertrophied calf muscles; what is the expected strength in his legs?
|
This is actually pseudohypertrophy due to fibrofatty replacement of the muscle and you would expect muscle weakness
|
|
True or False: Duchenne's muscular dystrophy is associated with cardiac myopathy.
|
true
|
|
True or False: Gower's maneuver indicates proximal lower limb weakness.
|
true
|
|
What aspect of the dystrophin gene makes it particularly susceptible to mutation?
|
The dystrophin gene (DMD) is the largest known human gene, which allows a high rate of spontaneous mutations
|
|
What is the role of dystrophin in the muscle?
|
Dystrophin helps to anchor muscle fibers
|
|
What two tissues rely most on the anchoring function of dystrophin?
|
Skeletal and cardiac muscle
|
|
Is Becker's muscular dystrophy more or less severe than Duchenne's muscular dystrophy?
|
Becker's muscular dystrophy is less severe and presents later in life
|
|
Muscular dystrophies can be diagnosed with the biopsy of _____ _____ and elevated _____ _____ levels in serum.
|
skeletal muscle; creatine phosphokinase (CPK)
|
|
Fragile X syndrome is caused by a defect in which gene?
|
FMR1
|
|
A defect in the FMR1 gene leads to what disease?
|
fragile x syndrome
|
|
What is the pattern of inheritance of fragile X syndrome?
|
x-linked recessive
|
|
True or False: Fragile X syndrome is caused by abnormal methylation of the FMR1 gene that alters its expression.
|
true
|
|
What is the most common genetic cause of mental retardation?
|
down syndrome
|
|
What is the second most common genetic cause of mental retardation?
|
fragile x syndrome
|
|
A male patient has a long face, a large jaw, large ears, autism, and macroorchidism. What is the most likely diagnosis?
|
fragile x syndrome (remember: Fragile X = eXtra large testes, jaw, ears)
|
|
True or False: Fragile X syndrome is associated with atrophic testes.
|
False; fragile X syndrome is associated with macroorchidism
|
|
What triplet is expanded in fragile X syndrome?
|
CGG - Chromosomes Get Gouged
|
|
True or False: Fragile X syndrome is associated with chromosomal breakage.
|
true
|
|
True or False: Huntington's disease is considered a trinucleotide expansion disease.
|
True (remember: Try (trinucleotide) hunting for my fried eggs [X])
|
|
Name four trinucleotide repeat disorders?
|
Huntington's disease, myotonic dystrophy, friedrich's ataxia and fragile X syndrome
|
|
True or False: Myotonic dystrophy is considered a trinucleotide expansion disease.
|
True (remember: Try (trinucleotide) hunting for my fried eggs [X])
|
|
True or False: Friedreich's ataxia is considered a trinucleotide expansion disease.
|
True (remember: Try (trinucleotide) hunting for my fried eggs [X])
|
|
True or False: Fragile X syndrome is considered a trinucleotide expansion disease.
|
True (remember: Try (trinucleotide) hunting for my fried eggs [X])
|
|
True or False: Duchenne's muscular dystrophy is considered a trinucleotide expansion disease.
|
False; Duchenne's muscular dystrophy does not involve trinucleotide repeat expansion
|
|
True or False: Achondroplasia is considered a trinucleotide expansion disease.
|
False; achondroplasia does not involve trinucleotide repeat expansion
-- it is autosomal dominant and associated with advanced paternal age |
|
True or False: Trinucleotide repeat expansion diseases may show anticipation.
|
true-- with successive generations the repeats and thus severity of the disease becomes worse and the age of onset becomes earlier
|
|
Anticipation involves a(n) _____ (increase/decrease) in disease severity and a(n) _____ (earlier/later) age of onset in successive generations.
|
increase; earlier
|
|
Will a father with the fragile X gene pass on an expanded gene sequence to his children?
|
No, germline expansion of this trinucleotide repeat occurs in females
|
|
Myotonic dystrophy is associated with a _____ (CTG/CGG) repeat, while fragile X syndrome has a _____ (CTG/CGG) repeat.
|
CTG; CGG (remember: myoTonic dystrophy = CTG, fraGile X = CGG)
|
|
Huntington's disease has a _____ repeat, while Friedreich's ataxia is a repeat of _____ nucleotides.
|
CAG; GAA
|
|
What is the most common chromosomal disorder?
|
down syndrome- trisomy 21
|
|
True or False: Friedreich's ataxia is considered a trinucleotide expansion disease.
|
True (remember: Try (trinucleotide) hunting for my fried eggs [X])
|
|
True or False: Fragile X syndrome is considered a trinucleotide expansion disease.
|
True (remember: Try (trinucleotide) hunting for my fried eggs [X])
|
|
True or False: Duchenne's muscular dystrophy is considered a trinucleotide expansion disease.
|
False; Duchenne's muscular dystrophy does not involve trinucleotide repeat expansion
|
|
True or False: Achondroplasia is considered a trinucleotide expansion disease.
|
False; achondroplasia does not involve trinucleotide repeat expansion
-- it is autosomal dominant and associated with advanced paternal age |
|
True or False: Trinucleotide repeat expansion diseases may show anticipation.
|
true-- with successive generations the repeats and thus severity of the disease becomes worse and the age of onset becomes earlier
|
|
Anticipation involves a(n) _____ (increase/decrease) in disease severity and a(n) _____ (earlier/later) age of onset in successive generations.
|
increase; earlier
|
|
Will a father with the fragile X gene pass on an expanded gene sequence to his children?
|
No, germline expansion of this trinucleotide repeat occurs in females
|
|
Myotonic dystrophy is associated with a _____ (CTG/CGG) repeat, while fragile X syndrome has a _____ (CTG/CGG) repeat.
|
CTG; CGG (remember: myoTonic dystrophy = CTG, fraGile X = CGG)
|
|
Huntington's disease has a _____ repeat, while Friedreich's ataxia is a repeat of _____ nucleotides.
|
CAG; GAA
|
|
What is the most common chromosomal disorder?
|
down syndrome- trisomy 21
|
|
A patient has a flat facial profile, prominent epicanthal folds, and a simian crease. This patient also has mental retardation. What is the most likely diagnosis?
|
down syndrome
|
|
A newborn is diagnosed with Down syndrome. She is vomiting bilious material. What is the most likely cause?
|
duodenal atresia
|
|
A newborn is diagnosed with Down syndrome. He has a heart murmur on examination. What is the most likely cause?
|
atrial septal defect (ASD)
|
|
What type of atrial septal defect is most common in patients with Down syndrome?
|
septum-primum type
|
|
Patients with Down syndrome who are more than 35 years old have an increased risk of what neurodegenerative disease?
|
Alzheimer's disease
|
|
Patients with Down syndrome have an increased risk of what type of leukemia?
|
acute lymphoblastic/lymphocytic leukemia (ALL)
|
|
Ninety-five percent of cases of Down syndrome are caused by the _____ of homologous chromosomes during the cell division process of _____.
|
nondisjunction; meiosis
|
|
Risk of having a baby with down syndrome is associated with what maternal factor?
|
advanced maternal age
|
|
True or False: More cases of Down syndrome are caused by Down mosaicism than by Robertsonian translocations.
|
False; 4% of cases are caused by Robertsonian translocations, whereas only 1% are caused by Down mosaicism
|
|
Prenatal testing reveals low levels of α-fetoprotein, high levels of β-human chorionic gonadotropin, and increased nuchal translucency. What is the most likely diagnosis?
|
down syndrome
|
|
What four substances are measured in the quad screen for Down syndrome?
|
alpha fetoprotein, beta human chorionic gonadotropin, estriol, and inhibin A
|
|
What would the levels of inhibin A and estriol be in maternal serum if the fetus has Down syndrome?
|
inhibin A is increased; estriol is decreased
|
|
True or False: Down syndrome that is a result of mosaicism is highly associated with maternal age.
|
False; Down mosaicism does not have any maternal association
|
|
Down syndrome is also known as trisomy _____.
|
21 (remember: Drinking age = 21, Down syndrome)
|
|
Which trisomy is the most common: 13 18, or 21?
|
21 (1:700)
|
|
Which trisomy is the least common: 13, 18, or 21?
|
13 (1:15,000)
|
|
What is the other name for trisomy 18?
|
Edwards' syndrome (remember: Election age = 18)
|
|
A baby has low-set ears, micrognathia, a prominent occiput, rocker bottom feet, and clenched hands. What is the most likely diagnosis?
|
Edwards' syndrome - trisomy 18
|
|
True or False: Trisomy 18 is associated with normal intellectual capacity but many dysmorphic features, such as rocker bottom feet, micrognathia, and a prominent occiput.
|
False; trisomy 18 is associated with severe mental retardation
|
|
True or False: It is common for patients with trisomy 18 to live into early adolescence.
|
False; patients with trisomy 18 usually die within the first year of life
|
|
A newborn has microphthalmia, microcephaly, cleft lip, cleft palate, and polydactyly. What is the most likely diagnosis?
|
patau's syndrome- trisomy 13
|
|
Patau's syndrome is also known as trisomy _____.
|
13 (remember: Puberty = 13, Patau)
|
|
True or False: Trisomy 13 is associated with cardiac defects and abnormal forebrain structures.
|
true- holoprocencephaly- forebrain fails to develop into 2 hemispheres
|
|
True or False: Newborns with trisomy 13 and newborns with trisomy 18 have similar expected life spans.
|
True; infants with both of these conditions are expected to die before the age of 1 year
|
|
The life expectancy for patients with trisomy 21 is _____ (<1 year/20-40 years/45-50 years).
|
45-50 years
|
|
True or False: Edward's syndrome is the least common autosomal trisomy.
|
False; the incidence of Patau's is 1:15,000, less than that of Edward's syndrome, which is 1:8000
|
|
What is a Robertsonian translocation?
|
It is a nonreciprocal translocation of chromosome pairs, such that chromosomes carry genetic information in an uneven manner
|
|
Name 5 chromosomes commonly involved in Robertsonian translocations.
|
13, 14, 15, 21, 22
|
|
What makes chromosomes 13, 14, 15, 21, and 22 candidates for Robertsonian translocations?
|
They are acrosomal chromosomes, which means that the centromere is located near one end rather than in the middle
|
|
How do acrosomal chromosomes align to create a Robertsonian translocation?
|
The long arms match up and fuse at the centromere, losing the short arms of the chromosomes
|
|
Does a Robertsonian translocation always result in a loss of genetic material?
|
A balanced translocation retains all genetic material and will not have any abnormal phenotype; if the translocation is unbalanced, genetic material is lost and abnormalities result
|
|
True or False: An unbalanced Robertsonian translocation may cause a chromosomal imbalance, but rarely miscarriage or stillbirth.
|
False; unbalanced translocations may result in miscarriage, stillbirth, or chromosomal imbalance such as Down or Patau's syndrome
|
|
The two types of chromosomal inversions are called _______ and _____inversions.
|
pericentric, paracentric
|
|
In chromosomal inversions, _____ (pericentric/paracentric) inversion involves the centromere.
|
pericentric (perIcentric = Includes the centromere)
|
|
In chromosomal inversions, _____ (pericentric/paracentric) inversion proceeds through meiosis.
|
pericentric-- because it includes the centromere and centromeres are needed for meiosis
|
|
In chromosomal inversions, _____ (pericentric/paracentric) inversion does not involve the centromere.
|
paracentric
|
|
In chromosomal inversions, _____ (pericentric/paracentric) inversion does not proceed through meiosis.
|
paracentric- does not include the centromere and thus cannot complete meiosis
|
|
How does a chromosomal inversion modify the affected chromosome?
|
It reverses one segment of the chromosome end-to-end
|
|
What is the effect of a chromosomal inversion on fertility?
|
Fertility is decreased
|
|
Cri-du-chat syndrome is caused by a deletion of the _____ arm of chromosome ____.
|
short; 5
|
|
The deletion of the short arm of chromosome 5 leads to what disease?
|
cri-du-chat syndrome
|
|
A newborn has microcephaly and epicanthal folds and produces a high-pitched crying or mewing sound. What is the most likely diagnosis?
|
cri-du-chat syndrome
|
|
True or False: Cri-du-chat syndrome is associated with cardiac abnormalities.
|
true
|
|
True or False: Patients with cri-du-chat syndrome are expected to have normal intelligence.
|
False; cri-du-chat syndrome is associated with severe mental retardation
|
|
What disease is caused by a microdeletion of the long arm of chromosome 7?
|
william's syndrome
|
|
Among others, what connective tissue gene is deleted in Williams syndrome?
|
elastin
|
|
Patients with Williams syndrome typically have _____ (coarse/masked/elfin) facies.
|
elfin
|
|
A patient has an extreme friendliness towards strangers and cheerful disposition, with noted mental retardation and cardiovascular disease; what is the diagnosis?
|
william's syndrome
|
|
In spite of their mental retardation, in which cognitive area are patients with Williams syndrome typically advanced?
|
Patients with Williams syndrome typically have well-developed verbal skills
|
|
Microdeletions at chromosome 22q11 can present as a spectrum of diseases including which two recognized syndromes?
|
DiGeorge syndrome or velocardiofacial syndrome
|
|
What disease is caused by microdeletions at 22q11 and involves defects of the thymus, the parathyroid, and the heart?
|
DiGeorge syndrome
|
|
What disease is caused by microdeletions at 22q11 and involves defects of the palate, the face, and the heart?
|
velocardiofacial syndrome
|
|
True or False: 22q11 syndromes are associated with cleft palate.
|
true
|
|
True or False: 22q11 syndromes are associated with abnormal facies.
|
true
|
|
True or False: 22q11 syndromes are associated with thymic aplasia.
|
true
|
|
True or False: 22q11 syndromes are associated with cardiac defects.
|
true
|
|
True or False: 22q11 Syndromes are associated with B cell deficiency.
|
False; 22q11 syndromes are associated with T lymphocyte deficiency due to thymic aplasia
|
|
True or False: 22q11 syndromes are associated with thyroid aplasia.
|
False; 22q11 syndromes are associated with parathyroid aplasia
|
|
True or False: 22q11 Syndromes are associated with hypercalcemia.
|
False; 22q11 syndromes are associated with hypocalcemia due to parathyroid aplasia
|
|
Name 5 findings associated with 22q11 deletion syndromes.
|
Cleft palate, Abnormal facies, Thymic aplasia, Cardiac defects, Hypocalcemia secondary to parathyroid aplasia (CATCH-22)
|
|
What embryonic structures are altered in 22q11 syndromes?
|
These syndromes are due to aberrant development of the 3rd and 4th branchial pouches
|
|
True or False: 22q11 Syndromes are X-linked recessive and show anticipation.
|
False; 22q11 syndromes are due to microdeletions on chromosome 22 and have variable presentations
|
|
Is vitamin A fat soluble or water soluble?
|
fat soluble
|
|
Is vitamin D fat soluble or water soluble?
|
fat soluble
|
|
Is vitamin E fat soluble or water soluble?
|
fat soluble
|
|
Is vitamin K fat soluble or water soluble?
|
fat soluble
|
|
Vision is associated with which fat-soluble vitamin?
|
vitamin A
|
|
Bone calcification is associated with which fat-soluble vitamin?
|
Vitamin D
|
|
Calcium homeostasis is associated with which fat-soluble vitamin?
|
Vitamin D
|
|
Clotting factors are associated with which fat-soluble vitamin?
|
vitamin K
|
|
The most abundant form of which fat-soluble vitamin acts as an antioxidant?
|
Vitamin E
|
|
Is vitamin B1 fat soluble or water soluble?
|
water soluble
|
|
Are vitamins B2, B3, B5 and B6 fat soluble or water soluble?
|
water soluble
|
|
Is vitamin B12 fat soluble or water soluble?
|
water soluble
|
|
Is biotin fat soluble or water soluble?
|
water soluble
|
|
Is folate fat soluble or water soluble?
|
water soluble
|
|
Is vitamin C fat soluble or water soluble?
|
water soluble
|
|
Is thiamine fat soluble or water soluble?
|
Water soluble
thiamine = vitamin B1 |
|
Is riboflavin fat soluble or water soluble?
|
water soluble
riboflavin = vitamin B2 |
|
Is pantothenic acid fat soluble or water soluble?
|
water soluble
panthothenic acid = vitamin B5 |
|
Is cobalamin fat soluble or water soluble?
|
water soluble
cobalamine = vitamin B12 |
|
Are pyridoxine, pyridoxal, and pyridoxamine fat soluble or water soluble?
|
water soluble
pyridoxine = vitamin B6 |
|
Is ascorbic acid fat soluble or water soluble?
|
water soluble
ascorbic acid = vitamin C |
|
Which two water-soluble vitamins are associated with megaloblastic anemia?
|
folate and vitamin B12/cobalamine
|
|
Deficiency of which two water-soluble vitamins can cause macrocytic anemia?
|
folate and vitamin B12/cobalamine
|
|
Which water-soluble vitamin is associated with collagen synthesis?
|
Vitamin C (ascorbic acid)
|
|
Name two vitamins that serve as antioxidants.
|
Vitamin E and vitamin C
(vitamin A can too) |
|
The vitamin precursor to thiamine pyrophosphate is _____ (fat / water) soluble.
|
water- thiamine (vit B1)
|
|
The vitamin precursor to flavin adenine dinucleotide and flavin mononucleotide is _____ (fat / water) soluble.
|
water- riboflavin (vit B2)
|
|
The vitamin precursor to oxidized nicotinamide adenine dinucleotide is _____ (fat / water) soluble.
|
water- niacin (vit B3)
|
|
The vitamin precursor to coenzyme A is _____ (fat / water) soluble.
|
water- pantothenic acid (vit B5)
|
|
The vitamin precursor to pyridoxal phosphate is _____ (fat / water) soluble.
|
water- pyridoxine (vit B6)
|
|
Are the B-complex vitamins fat soluble or water soluble?
|
water- soluble
|
|
True or False: Biotin, folate, and vitamins C, A, and B12 are all water-soluble vitamins.
|
False; vitamin A is fat soluble, the rest are water soluble
|
|
All of the water-soluble vitamins easily wash out from the body, except for which two?
|
Vitamin B12 and folate (stored in the liver)
|
|
In which organ is folate stored?
|
liver
|
|
Excess vitamin C is _____ (excreted/stored), and excess vitamin B12 is _____ (excreted/stored).
|
excreted; stored
|
|
B-complex deficiencies often result in what three conditions?
|
dermatitis, glossitis and diarrhea
|
|
What is another name for vitamin A?
|
Retinol (remember Retinol is Vitamin-A, so think Retin-A)
|
|
True or False: A deficiency of vitamin A (retinol) leads to night blindness.
|
true
|
|
True or False: A deficiency of vitamin A (retinol) leads to dry skin.
|
true
|
|
Vitamin A is a constituent of what visual pigment?
|
retinal
|
|
What are the symptoms of vitamin A intoxication?
|
Vitamin A excess is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia
|
|
True or False: Vitamin A deficiency is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia.
|
False; these symptoms are associated with an excess of Vitamin A
|
|
What foods contain high amounts of vitamin A?
|
Vitamin A is found in liver (esp polar bear liver), and in leafy vegetables
|
|
Name two topical uses of vitamin A.
|
It can be used topically for wrinkles and for acne
|
|
What are the effects of taking large amounts of vitamin A during pregnancy?
|
It is a teratogen, and causes cleft palate and cardiac abnormalities
|
|
What is another name for vitamin B1?
|
thiamine
|
|
Beriberi is caused by a deficiency of which vitamin?
|
vitamin B1/ thiamine (spell beriberi as Ber1Ber1)
|
|
Wernicke-Korsakoff syndrome is caused by a deficiency of which vitamin?
|
vitamin B1/ thiamine
|
|
The vitamin precursor to coenzyme A is _____ (fat / water) soluble.
|
water- pantothenic acid (vit B5)
|
|
The vitamin precursor to pyridoxal phosphate is _____ (fat / water) soluble.
|
water- pyridoxine (vit B6)
|
|
Are the B-complex vitamins fat soluble or water soluble?
|
water- soluble
|
|
True or False: Biotin, folate, and vitamins C, A, and B12 are all water-soluble vitamins.
|
False; vitamin A is fat soluble, the rest are water soluble
|
|
All of the water-soluble vitamins easily wash out from the body, except for which two?
|
Vitamin B12 and folate (stored in the liver)
|
|
In which organ is folate stored?
|
liver
|
|
Excess vitamin C is _____ (excreted/stored), and excess vitamin B12 is _____ (excreted/stored).
|
excreted; stored
|
|
B-complex deficiencies often result in what three conditions?
|
dermatitis, glossitis and diarrhea
|
|
What is another name for vitamin A?
|
Retinol (remember Retinol is Vitamin-A, so think Retin-A)
|
|
True or False: A deficiency of vitamin A (retinol) leads to night blindness.
|
true
|
|
True or False: A deficiency of vitamin A (retinol) leads to dry skin.
|
true
|
|
Vitamin A is a constituent of what visual pigment?
|
retinal
|
|
What are the symptoms of vitamin A intoxication?
|
Vitamin A excess is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia
|
|
True or False: Vitamin A deficiency is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia.
|
False; these symptoms are associated with an excess of Vitamin A
|
|
What foods contain high amounts of vitamin A?
|
Vitamin A is found in liver (esp polar bear liver), and in leafy vegetables
|
|
Name two topical uses of vitamin A.
|
It can be used topically for wrinkles and for acne
|
|
What are the effects of taking large amounts of vitamin A during pregnancy?
|
It is a teratogen, and causes cleft palate and cardiac abnormalities
|
|
What is another name for vitamin B1?
|
thiamine
|
|
Beriberi is caused by a deficiency of which vitamin?
|
vitamin B1/ thiamine (spell beriberi as Ber1Ber1)
|
|
Wernicke-Korsakoff syndrome is caused by a deficiency of which vitamin?
|
vitamin B1/ thiamine
|
|
True or False: A deficiency of vitamin A (retinol) leads to dry skin.
|
true
|
|
Vitamin A is a constituent of what visual pigment?
|
retinal
|
|
What are the symptoms of vitamin A intoxication?
|
Vitamin A excess is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia
|
|
True or False: Vitamin A deficiency is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia.
|
False; these symptoms are associated with an excess of Vitamin A
|
|
What foods contain high amounts of vitamin A?
|
Vitamin A is found in liver (esp polar bear liver), and in leafy vegetables
|
|
Name two topical uses of vitamin A.
|
It can be used topically for wrinkles and for acne
|
|
What are the effects of taking large amounts of vitamin A during pregnancy?
|
It is a teratogen, and causes cleft palate and cardiac abnormalities
|
|
What is another name for vitamin B1?
|
thiamine
|
|
Beriberi is caused by a deficiency of which vitamin?
|
vitamin B1/ thiamine (spell beriberi as Ber1Ber1)
|
|
Wernicke-Korsakoff syndrome is caused by a deficiency of which vitamin?
|
vitamin B1/ thiamine
|
|
Vitamin B1 is the precursor to what cofactor?
|
thyamine pyrophosphate (TPP)
|
|
What vitamin is needed for the decarboxylation of α-ketoacids like pyruvate and α-ketoglutarate?
|
vitamin B1 (thiamine)-- to make cofactor thyamine pyrophosphate (TPP)
|
|
What is the role of thiamine in the TCA cycle?
|
It is a cofactor for α-ketoglutarate dehydrogenase
|
|
Which step in glycolysis requires thiamine?
|
TPP is needed as a cofactor for pyruvate dehydrogenase
|
|
What vitamin is needed as a cofactor for branched-chain amino acid dehydrogenase?
|
Vitamin B1 (thiamine)
|
|
What vitamin is needed for the activity of transketolase in the hexose monophosphate shunt?
|
Vitamin B1 (thiamine)
|
|
Are polyneuritis and muscle wasting characteristic of wet or dry beriberi?
|
dry beriberi
|
|
Is high-output cardiac failure caused by dilated cardiomyopathy and edema characteristic of wet or dry beriberi?
|
wet beriberi
|
|
True or False: Vitamin B1 deficiency in alcoholism occurs due to a reducing reaction between ethanol and thiamine.
|
False; the deficiency is secondary to malnutrition and malabsorption
|
|
A patient in the emergency room who has recent onset ophthalmoplegia, confusion, and ataxia; you suspect what disease process?
|
This is typical for Wernicke-Korsakoff syndrome
|
|
Name at least 4 neurologic symptoms seen in Wernicke-Korsakoff syndrome.
|
opthalmoplegia, ataxia, confusion, confabulations, memory loss, personality change
|
|
What is another name for vitamin B2?
|
riboflavin
|
|
Riboflavin is another name for what vitamin?
|
vitamin B2
|
|
Cheilosis and corneal vascularization occur as a result of a deficiency of which vitamin?
|
vitamin b2- riboflavin remember: the 2 C's)
|
|
What is cheilosis?
|
Inflammation of the lips, with scaling and fissures at the corners of the mouth; this is seen in vitamin B2 deficiency
|
|
Flavin adenine dinucleotide is derived from which vitamin?
|
riboflavin- vitamin B2 (remember: FAD and FMN are derived from riboFlavin, B2 = 2 ATP)
|
|
Flavin mononucleotide is derived from which vitamin?
|
riboFlavin- vitamin B2
|
|
True or False: Vitamin B2 gives rise to cofactors that participate in oxidation-reduction reactions.
|
true (FAD+ and FADH2)
|
|
What is another name for vitamin B3?
|
niacin
|
|
A deficiency of vitamin B3 (niacin) leads to what disease?
|
pellagra
|
|
Pellagra can be caused by what disease, which is caused by decreased tryptophan absorption?
|
Hartnup's disease
|
|
Pellagra can be caused by what syndrome, characterized by increased tryptophan metabolism?
|
malignant carcinoid syndrome
|
|
Pellagra can be caused by which drug as a result of decreased levels of vitamin B6 (pyridoxine)?
|
isoniazid (INH) for treatment of TB
|
|
How does isoniazid cause a niacin deficiency?
|
By depleting vitamin B6, the synthesis of niacin from tryptophan cannot occur
|
|
A patient being treated for hyperlipidemia complains of becoming red in the face after taking his medication; what drug is he taking?
|
niacin (vitamin b3)
|
|
What vitamin is the precursor of oxidized nicotinamide adenine dinucleotide and oxidized nicotinamide adenine dinucleotide phosphate?
|
niacin (vitamin B3)
|
|
What vitamin is the precursor of oxidized nicotinamide adenine dinucleotide and oxidized nicotinamide adenine dinucleotide phosphate?
|
Vitamin B3 (niacin) (remember: NAD derived from Niacin, B3 = 3 ATP)
|
|
Vitamin B3 can be derived from the amino acid _____ using vitamin ____.
|
tryptophan; vitamin B6 (pyridoxine)
|
|
What amino acid acts as the precursor of vitamin B3?
|
tryptophan
|
|
A patient has Hartnup's disease, causing malabsorption of neutral amino acids; what vitamin deficiency could occur?
|
niacin (vitamin B3)
|
|
What are the "3 D's" of pellagra?
|
diarrhea, dermatitis, dementia
|
|
True or False: In addition to diarrhea, dermatitis, and dementia, pellagra is also characterized by beefy glossitis.
|
true
|
|
What is another name for vitamin B5?
|
pantothenate (panthothenic acid)
|
|
What are the symptoms of vitamin B5 deficiency?
|
dermatitis, enteritis, alopecia, and adrenal insufficiency
|
|
What vitamin is a precursor of coenzyme A, a cofactor for acyl transfer?
|
vitamin B5- pantothenate (remember: pantothen-A is in Co-A)
|
|
What vitamin is a component of fatty acid synthase?
|
vitamin B5 (pantothenate)
|
|
Adrenal insufficiency may be caused by a deficiency of which vitamin?
|
vitamin B5 (pantothenate)
|
|
What is another name for vitamin B6?
|
pyridoxine
|
|
What are the symptoms of vitamin B6 deficiency?
|
Convulsions, hyperirritability, and peripheral neuropathy
|
|
A deficiency of vitamin B6 is inducible by what two drugs?
|
isoniazid (INH) and oral contraceptives (OCPs)
|
|
A 32-year-old man begins taking INH after a positive PPD. He presents with numbness and tingling in the extremities. What is the most likely cause of his peripheral neuropathy?
|
vitamin B6 deficiency due to INH
|
|
A 28-year-old presents to the ED with convulsions and hyperirritability one month after beginning treatment for tuberculosis. What deficiency is a possible cause of these symptoms?
|
vitamin B6 deficiency due to INH (isoniazid) therapy for TB
|
|
A 20-year-old woman is started on oral contraceptive pills for birth control. Soon after starting she reports numbness and tingling in the extremities. What deficiency is a possible cause of her peripheral neuropathy?
|
vitamin B6 deficiency induced by OCPs
|
|
Which vitamin is the precursor to pyridoxal phosphate?
|
vitamin B6 (pyridoxine)
|
|
Which vitamin is needed for transamination reactions?
|
vitamin B6 (pyridoxine)
|
|
Which vitamin is needed for decarboxylation reactions?
|
vitamin B6 (pyridoxine)
|
|
Which vitamin is needed as a cofactor for glycogen phosphorylase?
|
vitamin B6 (pyridoxine)
|
|
What vitamin is required for conversion of tryptophan to niacin?
|
vitamin B6 (pyridoxine)
|
|
Which vitamin is needed for heme synthesis?
|
vitamin B6 (pyridoxine)
|
|
Which vitamin is required for the synthesis of niacin from tryptophan?
|
vitamin B6 (pyridoxine)
|
|
A deficiency of _____ may be caused by the use of antibiotics or the ingestion of raw eggs.
|
biotin
|
|
What are the symptoms of biotin deficiency?
|
dermatitis, alopecia and enteritis
|
|
Biotin is required as a cofactor for _____ reactions.
|
carboxylation
|
|
What is another name for vitamin C?
|
Ascorbic acid
|
|
True or False: Biotin is a cofactor for the following reaction: conversion of pyruvate to oxaloacetate.
|
true
|
|
What disease is caused by a deficiency of vitamin C?
|
scurvy
|
|
True or False: Biotin is a cofactor for the follow reaction: acetyl-CoA → malonyl-CoA.
|
true
|
|
True or False: Biotin is a cofactor for the follow reaction: conversion of propionyl-CoA to methylmalonyl-CoA.
|
true
|
|
What enzyme requires a biotin cofactor to create oxaloacetate?
|
pyruvate carboxylase
|
|
What enzyme requires a biotin cofactor to create malonyl-CoA?
|
acetyl CoA carboxylase
|
|
What enzyme requires a biotin cofactor to create methylmalonyl-CoA?
|
Propionyl-CoA carboxylase
|
|
True or false: Biotin deficiency is a very common vitamin deficiency that results in dermatitis, alopecia, and enteritis
|
False; this is a rare deficiency, but when seen presents with dermatitis, alopecia, and enteritis
|
|
A patient has swollen gums, bruising, anemia, and poor wound healing. What vitamin deficiency is probably responsible for these symptoms?
|
vitamin C deficiency
|
|
List four symptoms that are associated with scurvy.
|
bruising, swollen gums, anemia, and poor wound healing
|
|
Vitamin C is needed for the addition of _____ groups to the amino acids lysine and proline during collagen synthesis.
|
hydroxyl
|
|
Vitamin C _____ (promotes/inhibits) iron absorption by keeping it in the _____ (reduced/oxidized) state, which is more absorbable.
|
promotes; reduced
|
|
True or False: Vitamin C is required for the conversion of dopamine to norepinephrine.
|
true- it is required as a cofactor for the enzyme dopamine beta hydroxylase (DBH)
|
|
How can a patient increase their dietary intake of vitamin C?
|
By eating more fruits and vegetables; British sailors carried limes to prevent scurvy (origin of the word "limey")
|
|
What function does vitamin C share with vitamin E?
|
Both are antioxidants
|
|
What enzyme uses ascorbic acid to convert dopamine to NE?
|
dopamine beta hydroxylase
|
|
Is vitamin D2 found in plants or produced in sun-exposed skin?
|
plants
|
|
What is another name for vitamin D2?
|
ergocalciferol
|
|
What form of vitamin D is found in vitamins and other pharmaceuticals?
|
Vitamin D2
|
|
Is vitamin D3 found in plants or produced in sun-exposed skin?
|
produced in sun-exposed skin
|
|
When drinking a glass of milk, what type of vitamin D are you absorbing?
|
Vitamin D3 (remember: drinking milk (fortified with vitamin D) is good for bones)
|
|
What is another name for vitamin D3?
|
cholecalciferol
|
|
What is the storage form of vitamin D?
|
25-OH D3
|
|
What is the active form of vitamin D3?
|
1,25- dihydroxy vitamin D3 = calcitriol
|
|
A deficiency of vitamin D causes what disease in children?
|
rickets- bending of bones
|
|
A deficiency of vitamin D causes what disease in adults?
|
osteomalacia (soft bones)
|
|
A deficiency of vitamin D may lead to ______ (hypocalcemia/hypercalcemia) and ______ (flaccid muscles/tetany).
|
hypocalcemia and tetany
|
|
Vitamin D increases the absorption of what two types of ions in the intestine?
|
calcium and phosphate
|
|
What is the effect of vitamin D on your bones?
|
it increases resorption
|
|
A patient has hypercalcemia, loss of appetite, and stupor. What vitamin excess is probably responsible for these symptoms?
|
vitamin D
|
|
In what disease do epithelioid macrophages convert vitamin D into its active form, leading to hypercalcemia?
|
sarcoidosis
|
|
A deficiency of vitamin E leads to the increased fragility of what cell type?
|
erythrocytes
|
|
True or False: Vitamin E protects erythrocytes from hemolysis.
|
True (remember: E is for Erythrocytes)
(as an antioxidant it protects them from free radical damage) |
|
True or False: Vitamin E is an antioxidant.
|
true
|
|
What type of anemia is seen in vitamin E deficiency?
|
Hemolytic anemia
|
|
A patient presents with hemolytic anemia, muscle weakness, and neuropathy; what vitamin deficiency do you suspect?
|
vitamin E deficiency
|
|
Vitamin K deficiency leads to _____ (increased/decreased/normal) prothrombin time, _____ (increased/decreased/normal) activated partial thromboplastin time, and _____ (increased/decreased/normal) bleeding time.
|
increased; increased; normal
|
|
True or False: Vitamin K deficiency elevates prothrombin time.
|
true
|
|
True or False: Vitamin K deficiency elevates activated partial thromboplastin time.
|
true
|
|
True or False: Vitamin K deficiency elevates bleeding time.
|
False; vitamin K deficiency has no effect on bleeding time
|
|
True or False: Neonates are relatively deficient in vitamin K when they are born, which can predispose them to hemorrhage.
|
true-- so they get a vitamin K shot after birth (the gut bacteria makes the vitamin K and their gut flora is not fully developed)
|
|
What characteristic of neonates' intestines predisposes babies to hemorrhage? How is it prevented?
|
The neonatal intestine is sterile and thus cannot synthesize vitamin K; to prevent hemorrhage, all newborns are given a vitamin K injection at birth
|
|
Vitamin K is required for the ______ of the glutamic acid residues of factors II, VII, IX, and X and proteins C and S.
|
γ-Carboxylation
|
|
Which residues of factors II, VII, IX, and X and proteins C and S are γ-carboxylated by vitamin K?
|
Glutamic acid
|
|
Vitamin K is required for the γ-carboxylation of which four coagulation factors?
|
Factors II, VII, IX, and X
|
|
Vitamin K is required for which anticoagulation factors?
|
Proteins C and S
|
|
Which clotting factors are dependent on vitamin K?
|
Factors II, VII, IX, and X and proteins C and S
|
|
What synthesizes vitamin K in the gut?
|
Vitamin K is synthesized by intestinal bacteria
|
|
What is the effect of vitamin D on your bones?
|
it increases resorption
|
|
A patient has hypercalcemia, loss of appetite, and stupor. What vitamin excess is probably responsible for these symptoms?
|
vitamin D
|
|
In what disease do epithelioid macrophages convert vitamin D into its active form, leading to hypercalcemia?
|
sarcoidosis
|
|
A deficiency of vitamin E leads to the increased fragility of what cell type?
|
erythrocytes
|
|
True or False: Vitamin E protects erythrocytes from hemolysis.
|
True (remember: E is for Erythrocytes)
(as an antioxidant it protects them from free radical damage) |
|
True or False: Vitamin E is an antioxidant.
|
true
|
|
What type of anemia is seen in vitamin E deficiency?
|
Hemolytic anemia
|
|
A patient presents with hemolytic anemia, muscle weakness, and neuropathy; what vitamin deficiency do you suspect?
|
vitamin E deficiency
|
|
Vitamin K deficiency leads to _____ (increased/decreased/normal) prothrombin time, _____ (increased/decreased/normal) activated partial thromboplastin time, and _____ (increased/decreased/normal) bleeding time.
|
increased; increased; normal
|
|
True or False: Vitamin K deficiency elevates prothrombin time.
|
true
|
|
True or False: Vitamin K deficiency elevates activated partial thromboplastin time.
|
true
|
|
True or False: Vitamin K deficiency elevates bleeding time.
|
False; vitamin K deficiency has no effect on bleeding time
|
|
True or False: Neonates are relatively deficient in vitamin K when they are born, which can predispose them to hemorrhage.
|
true-- so they get a vitamin K shot after birth (the gut bacteria makes the vitamin K and their gut flora is not fully developed)
|
|
What characteristic of neonates' intestines predisposes babies to hemorrhage? How is it prevented?
|
The neonatal intestine is sterile and thus cannot synthesize vitamin K; to prevent hemorrhage, all newborns are given a vitamin K injection at birth
|
|
Vitamin K is required for the ______ of the glutamic acid residues of factors II, VII, IX, and X and proteins C and S.
|
γ-Carboxylation
|
|
Which residues of factors II, VII, IX, and X and proteins C and S are γ-carboxylated by vitamin K?
|
Glutamic acid
|
|
Vitamin K is required for the γ-carboxylation of which four coagulation factors?
|
Factors II, VII, IX, and X
|
|
Vitamin K is required for which anticoagulation factors?
|
Proteins C and S
|
|
Which clotting factors are dependent on vitamin K?
|
Factors II, VII, IX, and X and proteins C and S
|
|
What synthesizes vitamin K in the gut?
|
Vitamin K is synthesized by intestinal bacteria
|
|
True or False: Vitamin K deficiency can occur after the prolonged use of antibiotics.
|
true since it wipes out the gut flora that make the vit K
|
|
What drug is a vitamin K antagonist?
|
warfarin (coumadin)
|
|
A patient has delayed wound healing, hypogonadism, and decreased axillary, facial, and pubic hair. What nutritional deficiency is likely to be responsible for these symptoms?
|
zinc deficiency
|
|
True or False: Zinc deficiency may predispose an individual to alcoholic cirrhosis.
|
true
|
|
True or False: Zinc deficiency is associated with decreased axillary, facial, and pubic hair.
|
true
|
|
True or False: Zinc deficiency is associated with hypergonadism.
|
False; zinc deficiency is associated with hypogonadism
|
|
What is the importance of zinc fingers?
|
Zinc fingers allow transcription factors and other molecules to interact with DNA
|
|
What is the limiting reagent in alcohol metabolism?
|
Nicotinamide adenine dinucleotide (NAD+)
|
|
What intermediate of alcohol metabolism accumulates when a person takes the drug disulfiram?
|
acetaldehyde
|
|
What enzyme does disulfiram inhibit?
|
Acetaldehyde dehydrogenase
|
|
True or False: Disulfiram produces symptoms of nausea, vomiting, and headache as a result of the accumulation of acetaldehyde.
|
true
|
|
A patient taking fomepizole would have a decreased accumulation of _____ because it inhibits _____.
|
acetaldehyde; alcohol dehydrogenase; fomepizole is used in cases of methanol poisoning
|
|
Where in the cell is the reaction that is inhibited by fomepizole?
|
Fomepizole blocks the action of alcohol dehydrogenase, which is in the cytosol
|
|
Where in the cell is the reaction that is inhibited by disulfiram?
|
Disulfiram inhibits acetaldehyde dehydrogenase, which is in the mitochondria
|
|
What happens to the rate of ethanol metabolism by alcohol dehydrogenase as more ethanol is consumed?
|
There is no change in the rate since this reaction proceeds by zero-order kinetics
|
|
Ethanol metabolism _____ (increases/decreases) the NADH/NAD+ ratio in the liver, which _____ (promotes/inhibits) gluconeogenesis.
|
increases; inhibits
|
|
Ethanol ingestion leads to the increased conversion of pyruvate to _____ and oxaloacetate to _____, because these reactions regenerate NAD+ from NADH.
|
lactate; malate
|
|
The high NADH/NAD+ ratio seen after ethanol ingestion is responsible for the shunting of metabolites away from _____ and toward _____ _____ synthesis.
|
Gluconeogenesis; fatty acid
|
|
Ethanol metabolism ultimately results in _____ as a result of the inhibition of gluconeogenesis, and hepatocellular _____ from increased fatty acid synthesis.
|
Hypoglycemia, steatosis
|
|
What by-product of ethanol metabolism is responsible for hepatic steatosis?
|
The accumulation of NADH drives pyruvate to lactate and oxaloacetate to malate, resulting in decreased gluconeogenesis and increased fatty acid synthesis
|
|
Kwashiorkor is the result of a deficiency of _____ in the diet.
|
protein
|
|
A malnourished child is also anemic, edematous, and has elevated LFTs; what is the diagnosis?
|
kwashiorkor (remember: Kwashiorkor results from a protein-deficient MEAL: Malnutrition, Edema, Anemia, Liver (fatty))
|
|
True or False: Kwashiorkor is associated with skin lesions.
|
true
|
|
True or False: Kwashiorkor is associated with fatty change of the liver.
|
true
|
|
True or False: Kwashiorkor is associated with edema.
|
true
|
|
A malnourished child has a swollen, edematous belly. Is she more likely to have kwashiorkor or marasmus?
|
Kwashiorkor
|
|
Marasmus is the result of a deficiency of _____ in the diet.
|
Calories (all nutrients)
|
|
A child presents with tissue and muscle wasting, loss of subcutaneous fat, and variable edema. Is she more likely to have kwashiorkor or marasmus?
|
marasmus
|
|
A malnourished child has significant tissue wasting. Is she more likely to have kwashiorkor or marasmus?
|
Marasmus (remember: Marasmus results in Muscle wasting)
|
|
Kwashiorkor is a deficiency of _____ that results in skin lesions, anemia, edema, and liver malfunction (fatty change). By contrast, marasmus is a deficiency of _____ that results in tissue wasting.
|
protein; calories
|
|
Fatty acid oxidation occurs in the _____ (mitochondria/cytoplasm), whereas fatty acid synthesis occurs in the _____ (mitochondria/cytoplasm).
|
mitchondria; cytoplasm
|
|
Glycolysis occurs in the _____ (mitochondria/cytoplasm), whereas the Krebs cycle occurs in the _____ (mitochondria/cytoplasm).
|
cytoplasm; mitochondria
|
|
Where in the cell are the enzymes of the hexose monophosphate shunt located?
|
cytoplasm
|
|
Where in the cell does acetyl coenzyme A production occur?
|
mitochondria
|
|
Protein synthesis occurs on the _____ (rough/smooth) endoplasmic reticulum, whereas steroid synthesis occurs on the _____ (rough/smooth) endoplasmic reticulum.
|
rough; smooth
|
|
Name the three pathways that occur in both the cytoplasm and the mitochondria.
|
Heme synthesis, Urea cycle, Gluconeogenesis (remember the mnemonic: HUGs take two)
|
|
Name four pathways that occur in the mitochondria.
|
Fatty acid oxidation, acetyl-CoA production, Krebs cycle, and oxidative phosphorylation
|
|
Fatty acid oxidation occurs in the _____ (mitochondria/cytoplasm).
|
mitochrondia
|
|
Acetyl-CoA production occurs in the _____ (mitochondria/cytoplasm).
|
mitochondria
|
|
The Krebs cycle occurs in the _____ (mitochondria/cytoplasm).
|
mitochondria
|
|
What enzyme uses ATP to add a high-energy phosphate group onto a substrate?
|
kinase
|
|
what enzyme adds inorganic phosphate onto substrate without using ATP?
|
phosphorylase
|
|
what enzyme removes phosphate group from substrates?
|
phosphatase
|
|
what enzyme oxidizes substrates?
|
dehydrogenase
|
|
what enzyme adds 1 carbon with the help biotin to substrates?
|
carboxylase
|
|
What is the rate-determining enzyme of de novo pyrimidine synthesis?
|
carbamoyl phosphate synthetase II
|
|
carbamoyl phosphate synthetase II is the rate-limiting enzyme of which metabolic process?
|
de novo pyrimidine synthesis
|
|
What is the rate-determining enzyme of de novo purine synthesis?
|
glutamine-PRPP amidotransferase
|
|
Glutamine-PRPP amidotransferase is the rate-limiting enzyme of which metabolic process?
|
de novo purine synthesis
|
|
What is the rate-determining enzyme of glycolysis?
|
phosphofructokinase-1 (PFK-1)
|
|
Phosphofructokinase-1 is the rate-limiting enzyme of which metabolic process?
|
glycolysis
|
|
What is the rate-determining enzyme of gluconeogenesis?
|
fructose- 1,6 bisphosphatase
|
|
fructose- 1,6 bisphosphatase is the rate-limiting enzyme of which metabolic process?
|
gluconeogenesis
|
|
What is the rate-determining enzyme of the TCA cycle?
|
isocitrate dehydrogenase
|
|
Isocitrate dehydrogenase is the rate-limiting enzyme of which metabolic process?
|
TCA/Krebs cycle
|
|
What is the rate-determining enzyme of glycogen synthesis?
|
glycogen synthase
|
|
Glycogen synthase is the rate-limiting enzyme of which metabolic process?
|
glycogen synthesis
|
|
What is the rate-determining enzyme of glycogenolysis?
|
glycogen phosphorylase
|
|
Glycogen phosphorylase is the rate-limiting enzyme of which metabolic process?
|
glycogenolysis
|
|
What is the rate-determining enzyme of the HMP shunt?
|
glucose 6 phosphate dehydrogenase (G6PD)
|
|
Glucose-6-phosphate dehydrogenase is the rate-limiting enzyme of which metabolic process?
|
the HMP shunt (purpose is to provide NADPH for reductive reactions like glutatione inside RBCs)
|
|
What is the rate-determining enzyme of fatty acid synthesis?
|
acetyl-CoA carboxylase (ACC)
|
|
Acetyl-CoA carboxylase is the rate-limiting enzyme of which metabolic process?
|
fatty acid synthesis
|
|
What is the rate-determining enzyme of fatty acid oxidation?
|
carnitine acyltransferase I
|
|
Carnitine acyltransferase I is the rate-limiting enzyme of which metabolic process?
|
Fatty acid oxidation
|
|
What is the rate-determining enzyme of ketogenesis?
|
HMG-CoA synthase
|
|
HMG-CoA synthase is the rate-limiting enzyme of which metabolic process?
|
ketogenesis
|
|
What is the rate-determining enzyme of cholesterol synthesis?
|
HMG CoA reductase (statins inhibit this)
|
|
HMG-CoA reductase is the rate-limiting enzyme of which metabolic process?
|
cholesterol synthesis
|
|
What is the rate-determining enzyme of the urea cycle?
|
carbamoyl phosphate synthetase I
|
|
Carbamoyl phosphate synthetase is the rate-limiting enzyme of which metabolic process?
|
urea cycle
|
|
What is the name of the molecule that is composed of adenine, ribose, three phosphoryl groups, and two phosphoanhydride bonds?
|
ATP
|
|
In which two organs are ATPs produced from the aerobic metabolism of glucose via the malate-aspartate shuttle?
|
heart and liver
|
|
How many ATP molecules are produced from the aerobic metabolism of glucose via the malate-aspartate shuttle?
|
32 ATP (this is NADH entering the mitochondria from the cytosol-- if it uses this shuttle it yields 3 ATP per NADH)
|
|
How many ATP molecules are produced from the aerobic metabolism of glucose via the glyceraldehyde-3-phosphate shuttle?
|
30 ATP- this occurs in muscle
|
|
More ATP molecules are produced from glucose if the _____ (malate-aspartate shuttle/glyceraldehyde-3-phosphate shuttle) is used.
|
malate-aspartate shuttle
|
|
Where does the energy come from in order to proceed from substrate to product in energetically unfavorable reactions?
|
The hydrolysis of ATP can be coupled with energetically unfavorable reactions to produce enough net energy
|
|
What is the net gain of ATP molecules after a molecule of glucose has participated in anaerobic glycolysis?
|
2 ATP the NADH created cannot be used to generate energy without oxygen
|
|
A glucose molecule is metabolized to the level of pyruvate and lactate; is this process an anaerobic or aerobic process?
|
An anaerobic process; no oxygen has been used in this reaction
|
|
Which ion helps stabilize the charged phosphoryl groups in the triphosphate moiety of ATP?
|
Mg2+
|
|
Name the three carriers of electrons.
|
NADH, NADPH, FADH2
|
|
What compounds are used as single-carbon donors in various reactions?
|
Tetrahydrofolates
|
|
What vitamin is the donor of the carboxyl group used in many biochemical reactions in the body?
|
biotin
|
|
What is the activated carrier for phosphoryl groups?
|
ATP
|
|
What molecule donates methyl groups?
|
S-adenosylmethionine (SAM)
|
|
Which activated carrier molecule donates aldehyde groups?
|
Thiamin pyrophosphate (TPP)
|
|
Acyl groups are transported using which two activated carriers?
|
Coenzyme A and lipoamide
|
|
What pathway produces NADPH?
|
The hexose monophosphate (HMP) shunt
|
|
Do anabolic processes generally use NAD+ or NADPH?
|
NADPH (has more letters than NADH--thus it is built up--anabolic)
|
|
The synthesis of steroids is a(n) _____ (catabolic/anabolic) process that uses _____ (NAD+/NADPH) to donate electrons.
|
anabolic; NADPH
|
|
Catabolic processes generally use _____ (NAD+/NADPH) as an electron acceptor, whereas anabolic processes generally use _____ (NAD+/NADPH) as an electron donor.
|
NAD+; NADPH
|
|
The synthesis of fatty acids is a(n) _____ (catabolic/anabolic) process that uses _____ (NAD+/NADPH) to donate electrons.
|
anabolic; NADPH
|
|
Name the three universal electron acceptors.
|
NAD+, NADP+, FAD+
|
|
The respiratory burst in phagocytes uses what substance as an electron carrier?
|
NADPH
|
|
The cytochrome P-450 system uses what substance as an electron carrier?
|
NADPH
|
|
In what charged state do nicotinamides and flavin nucleotides accept electrons?
|
In the NAD+, NADP+, and FAD+ forms
|
|
In what state do nicotinamides and flavin nucleotides donate electrons?
|
In the NADH, NADPH, and FADH2 forms; these molecules provide reducing equivalents (remember that being reduced involves more bonds to hydrogens)
|
|
What is the enzymatic reaction performed by hexokinase and glucokinase?
|
Both enzymes phosphorylate glucose to form glucose-6-phosphate (first step of glycolysis- and glycogen synthesis in the liver)
|
|
In the liver, formation of glucose-6-phosphate is the first step of which 2 reactions?
|
glycolysis and glycogen synthesis
|
|
Which 2 locations in the body contain high concentrations of glucokinase?
|
The liver and beta cells of the pancreas
|
|
True or False: Hexokinase catalyzes the same reaction as glucokinase, but it is found throughout the body rather than localized primarily to the liver.
|
true
|
|
Which enzyme has a higher Km: glucokinase or hexokinase?
|
glucokinase (higher Km = lower affinity) --this enzyme has no feedback-inhibition loop with glucose-6-phosphate, because its job is to store excess energy after a meal
|
|
Which enzyme has a higher affinity for glucose: glucokinase or hexokinase?
|
hexokinase
|
|
Which enzyme has a higher affinity for glucose: glucokinase or hexokinase?
|
Hexokinase; this enzyme has a feedback-inhibition loop with glucose-6-phosphate, because its job is just to keep the cells supplied with energy
|
|
Which enzyme has a higher Vmax: glucokinase or hexokinase?
|
Glucokinase; this enzyme has no feedback-inhibition loop with glucose-6-phosphate, because its job is to store excess energy after a meal
|
|
Which enzyme has a greater capacity to convert glucose to glucose-6-phosphate: glucokinase or hexokinase?
|
Glucokinase; this enzyme has no feedback-inhibition loop with glucose-6-phosphate, because its job is to store excess energy after a meal
|
|
Which enzyme is inhibited by negative feedback from its product, glucose-6-phosphate: glucokinase or hexokinase?
|
Hexokinase; this enzyme has a feedback-inhibition loop with glucose-6-phosphate, because its job is just to keep the cells supplied with energy
|
|
True or False: Both glucokinase and hexokinase yield glucose-6-phosphate as a product, and both enzymes are inhibited by their product.
|
False; only hexokinase is inhibited by glucose-6-phosphate
|
|
True or False: Glucokinase phosphorylates excess glucose to sequester it in the liver as glucose-6-phosphate.
|
true
|
|
Which enzyme is induced by insulin: hexokinase or glucokinase?
|
glucokinase
|
|
What is the effect of glucokinase on the blood glucose level?
|
By storing excess glucose in the liver, the liver can act as a buffer to regulate the blood glucose level
|
|
Name the two enzymes that catalyze the reaction of glucose into glucose-6-phosphate.
|
Hexokinase and glucokinase
|
|
Where in the cell are the reactions that produce 2 pyruvate molecules from 1 glucose?
|
in the cytoplasm
|
|
What inhibits the activity of hexokinase during glycolysis?
|
Glucose-6-phosphate provides negative feedback
|
|
Name three compounds that decrease the activity of pyruvate dehydrogenase through negative feedback.
|
ATP, NADH, and acetyl-CoA are inhibitors of pyruvate dehydrogenase
|
|
In glycolysis, what enzyme catalyzes the formation of fructose-1,6 bisphosphate?
|
Phosphofructokinase-1
(rate-limiting step) |
|
In glycolysis, what enzyme catalyzes the formation of fructose-1,6 bisphosphate?
|
Phosphofructokinase-1
|
|
In glycolysis, what enzyme catalyzes the rate-limiting step?
|
Phosphofructokinase-1
|
|
In glycolysis, is ATP an activator or an inhibitor of phosphofructokinase-1 (the enzyme that catalyzes the rate-limiting step in glycolysis)?
|
inhibitor
|
|
True or False: In glycolysis, high levels of ATP and citrate in the cell increase the activity of phosphofructokinase-1 and lead to increased flux through the glycolytic pathway.
|
False; ATP and citrate inhibit phosphofructokinase-1 since glycolysis is unnecessary in an energy-replete cell
|
|
Is citrate an activator or an inhibitor of the enzyme that catalyzes the rate-limiting step in glycolysis?
|
inhibitor of phosphofructokinase-1
|
|
In glycolysis, fructose-2,6-bisphosphate _____ (increases/decreases) the production of fructose-1,6-bisphosphate from fructose-6-phosphate.
|
increases (through increasing activity of phosphofructokinase-1)
|
|
In glycolysis, is adenosine monophosphate an activator or an inhibitor of phosphofructokinase-1?
|
activator (signifies low energy state)
|
|
In glycolysis, fructose-1,6-bisphosphate _____ (increases/decreases) the activity of pyruvate kinase.
|
increases
|
|
Is fructose-2,6-bisphosphate an activator or an inhibitor of the enzyme that catalyzes the rate-limiting step in glycolysis?
|
activator
|
|
What enzyme catalyzes the conversion of phosphoenolpyruvate to pyruvate during glycolysis?
|
Pyruvate kinase
|
|
True or False: In glycolysis, ATP and alanine are inhibitors of pyruvate kinase and thus decrease the production of pyruvate when found in high concentrations in a cell.
|
true
|
|
In glycolysis, the formation of acetyl-CoA from pyruvate is catalyzed by what enzyme?
|
pyruvate dehydrogenase
|
|
True or False: In glycolysis, the reaction catalyzed by hexokinase is reversible.
|
False; this reaction is nonreversible
|
|
True or False: In glycolysis, the reaction catalyzed by glucokinase is reversible.
|
False; this reaction is nonreversible
|
|
True or False: In glycolysis, the reaction catalyzed by pyruvate kinase is reversible.
|
False; this reaction is nonreversible
|
|
True or False: In glycolysis, the reaction catalyzed by pyruvate dehydrogenase is reversible.
|
False; this reaction is nonreversible
|
|
True or False: Hexokinase is found mainly in the liver.
|
False; hexokinase is widely distributed in the body
|
|
In the reaction that produces glucose-6-phosphate from D-glucose, is ATP produced or required?
|
required (extra phosphate added--look at the names)
|
|
In the reaction that produces fructose-1,6-bisphosphate from fructose-6-phosphate, is ATP produced or required?
|
required (extra phosphate added--look at the names)
|
|
In the reaction that produces 3-phosphoglycerate from 1,3-bisphosphoglycerate, is ATP produced or required?
|
produced (phosphate lost--look at the names)
|
|
In the reaction that produces pyruvate from phosphoenolpyruvate, is ATP produced or required?
|
produced (an ATP is lost-- look at the names)
|
|
In glycolysis, the formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate is catalyzed by which enzyme?
|
Phosphoglycerate kinase
|
|
True of False: In glycolysis, the reaction catalyzed by phosphoglycerate kinase is reversible.
|
true
|
|
What is the most potent activator of phosphofructokinase-1?
|
Fructose-2,6-bisphosphate
|
|
The enzyme phosphofructokinase 2 catalyzes which reaction?
|
The conversion of fructose-6-phosphate to fructose-2,6-bisphosphate
|
|
What enzyme converts fructose-1,6-bisphosphate (F1,6BP) into fructose-6-phosphate during gluconeogenesis?
|
Fructose bisphosphatase-1 (FBPase-1)
|
|
What enzyme creates fructose-2,6-bisphosphate from fructose-6-phosphate?
|
Phosphofructokinase-2 (PFK-2)
|
|
Fructose bisphosphatase-2 catalyzes which reaction?
|
Conversion of fructose-2,6-bisphosphate into fructose-6-phosphate
|
|
What function do FBP-1 and FBP-2 have in common?
|
Both remove a phosphate group from their target; FBP-1 removes that from the 1 carbon of F1,6BP, while FBP-2 removes that from the 2 carbon of F2,6BP
|
|
What function do PFK-1 and PFK-2 have in common?
|
Both add a phosphate group to either the 1 carbon (in PFK-1) or the 2 carbon (in PFK-2) of fructose-6-phosphate
|
|
True or False: In glycolysis, ATP and alanine are inhibitors of pyruvate kinase and thus decrease the production of pyruvate when found in high concentrations in a cell.
|
true
|
|
In glycolysis, the formation of acetyl-CoA from pyruvate is catalyzed by what enzyme?
|
pyruvate dehydrogenase
|
|
True or False: In glycolysis, the reaction catalyzed by hexokinase is reversible.
|
False; this reaction is nonreversible
|
|
True or False: In glycolysis, the reaction catalyzed by glucokinase is reversible.
|
False; this reaction is nonreversible
|
|
True or False: In glycolysis, the reaction catalyzed by pyruvate kinase is reversible.
|
False; this reaction is nonreversible
|
|
True or False: In glycolysis, the reaction catalyzed by pyruvate dehydrogenase is reversible.
|
False; this reaction is nonreversible
|
|
True or False: Hexokinase is found mainly in the liver.
|
False; hexokinase is widely distributed in the body
|
|
In the reaction that produces glucose-6-phosphate from D-glucose, is ATP produced or required?
|
required (extra phosphate added--look at the names)
|
|
In the reaction that produces fructose-1,6-bisphosphate from fructose-6-phosphate, is ATP produced or required?
|
required (extra phosphate added--look at the names)
|
|
In the reaction that produces 3-phosphoglycerate from 1,3-bisphosphoglycerate, is ATP produced or required?
|
produced (phosphate lost--look at the names)
|
|
In the reaction that produces pyruvate from phosphoenolpyruvate, is ATP produced or required?
|
produced (an ATP is lost-- look at the names)
|
|
In glycolysis, the formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate is catalyzed by which enzyme?
|
Phosphoglycerate kinase
|
|
True of False: In glycolysis, the reaction catalyzed by phosphoglycerate kinase is reversible.
|
true
|
|
What is the most potent activator of phosphofructokinase-1?
|
Fructose-2,6-bisphosphate
|
|
The enzyme phosphofructokinase 2 catalyzes which reaction?
|
The conversion of fructose-6-phosphate to fructose-2,6-bisphosphate
|
|
What enzyme converts fructose-1,6-bisphosphate (F1,6BP) into fructose-6-phosphate during gluconeogenesis?
|
Fructose bisphosphatase-1 (FBPase-1)
|
|
What enzyme creates fructose-2,6-bisphosphate from fructose-6-phosphate?
|
Phosphofructokinase-2 (PFK-2)
|
|
Fructose bisphosphatase-2 catalyzes which reaction?
|
Conversion of fructose-2,6-bisphosphate into fructose-6-phosphate
|
|
What function do FBP-1 and FBP-2 have in common?
|
Both remove a phosphate group from their target; FBP-1 removes that from the 1 carbon of F1,6BP, while FBP-2 removes that from the 2 carbon of F2,6BP
|
|
What function do PFK-1 and PFK-2 have in common?
|
Both add a phosphate group to either the 1 carbon (in PFK-1) or the 2 carbon (in PFK-2) of fructose-6-phosphate
|
|
Which enzyme regulating the level of F2,6BP is active in the fed state?
|
Phosphofructokinase 2, increasing glycolysis and thus ATP creation for anabolic processes
|
|
Which enzyme regulating the level of F2,6BP is active in the fasting state?
|
Fructose bisphosphatase-2, increasing gluconeogenesis when glucose is needed for catabolic processes
|
|
A potent regulator of glycolysis, this compound activates the enzyme phosphofructokinase to produce fructose-1,6-bisphosphate.
|
Fructose-2,6-bisphosphate
|
|
A potent regulator of gluconeogenesis, this compound is converted to fructose-6-phosphate by the enzyme fructose bisphosphatase 2.
|
Fructose-2,6-bisphosphate
|
|
True or False: Fructose-2,6-bisphosphate is a potent regulator of both glycolysis and gluconeogenesis.
|
true
|
|
What will the activity level of PFK-1 be if it is in the presence of both F2,6BP, an activator, and citrate and ATP, two inhibitors?
|
It will actively convert F6P to F1,6BP because F2,6BP overrides any inhibition
|
|
In the fed state, does the cell perform glycolysis or gluconeogenesis? What enzyme is responsible?
|
glycolysis (When glucose is available, the body will perform glycolysis because PFK-2 is active and will increase the amount of F2,6BP)
|
|
In the fasting state, does the cell perform glycolysis or gluconeogenesis? What enzyme is responsible?
|
gluconeogenesis (The liver cell will perform gluconeogenesis because FBPase-2 is active and will decrease the amount of F2,6BP)
|
|
A patient with a genetic mutation in their glycolysis pathway is anemic; what is the likely etiology?
|
This is likely hemolytic anemia due to RBC swelling and lysis (no ATP to maintain Na+/K+ ATPase pump)-- sodium enters and stays inside-- water follows
|
|
What type of anemia is seen with decreased activity of erythrocyte Na+/K+ ATPase?
|
Hemolytic anemia
|
|
Why does inhibition of the erythrocyte Na+/K+ ATPase cause hemolytic anemia?
|
Inability to transfer ions results in cell swelling and lysis (sodium is trapped inside and water follows)
|
|
True or False: RBCs have mitochondria.
|
False; there are no mitochondria present in RBCs- thus they rely solely on glycolysis for energy
|
|
True or False: RBCs are able to metabolize glucose through oxidative phosphorylation.
|
False; RBCs have no mitochondria, which are the site of oxidative phosphorylation
|
|
True or False: RBCs depend solely on glycolysis to produce ATP from glucose.
|
true
|
|
True or False: 95% of glycolytic enzyme deficiencies are due to deficiencies specifically in pyruvate kinase.
|
true
|
|
True or False: 95% of glycolytic enzyme deficiencies are due to deficiencies specifically in phosphoglucose isomerase.
|
False; 4% of glycolytic enzyme deficiencies are due to deficiencies in phosphoglucose isomerase while 95% are due to deficiencies in pyruvate kinase
|
|
Name the most common glycolytic enzyme deficiency that leads to hemolytic anemia.
|
pyruvate kinase (this leads to continuous hemolytic anemia-- vs G6PD deficiency which is episodic with oxidative stress)
|
|
How many enzymes make up the pyruvate dehydrogenase complex?
|
Three
|
|
How many cofactors are required for pyruvate dehydrogenase complex activity?
|
Five
|
|
What is another name for vitamin B1?
|
Thiamine
|
|
Vitamin B1 is used as a cofactor in the pyruvate dehydrogenase complex as part of what compound?
|
Thiamine pyrophosphate
|
|
What is another name for vitamin B2?
|
Riboflavin
|
|
Vitamin B2 is used as a cofactor in the pyruvate dehydrogenase complex as part of what compound?
|
FAD+
|
|
What is another name for vitamin B3?
|
Niacin
|
|
What reaction is mediated by the α-ketoglutarate complex?
|
α-Ketoglutarate to succinyl-CoA in the TCA cycle
|
|
Vitamin B3 is used as a cofactor in the pyruvate dehydrogenase complex as part of what compound?
|
NAD+
|
|
What poison inhibits the function of the pyruvate dehydrogenase complex?
|
Arsenic
|
|
What is another name for vitamin B5?
|
Pantothenate
|
|
A sick patient has rice water stools, vomiting, and garlic breath; what is the diagnosis?
|
Arsenic poisoning
|
|
Vitamin B5 is used as a cofactor in the pyruvate dehydrogenase complex as part of what compound?
|
CoA
|
|
How does arsenic interfere with pyruvate dehydrogenase?
|
Arsenic inhibits lipoic acid
|
|
What enzyme catalyzes the conversion of pyruvate to acetyl-CoA?
|
Pyruvate dehydrogenase complex
|
|
Which cofactors are required for the activity of the pyruvate dehydrogenase complex?
|
B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenate), and lipoic acid
|
|
True or False: Pyruvate dehydrogenase complex is activated by the depletion of cell energy stores (eg, as occurs with exercise).
|
True
|
|
A(n) _____ (increase/decrease) in the NAD+/NADH ratio in a cell leads to increased activity of the pyruvate dehydrogenase complex.
|
Increase
|
|
A(n) _____ (increase/decrease) in the concentration of calcium in a cell leads to increased activity of the pyruvate dehydrogenase complex.
|
Increase
|
|
A(n) _____ (increase/decrease) in adenosine diphosphate in a cell leads to increased activity of the pyruvate dehydrogenase complex.
|
Increase
|
|
What enzyme in the citric acid cycle has a similar structure to the pyruvate dehydrogenase complex and uses the same cofactors?
|
The α-ketoglutarate dehydrogenase complex
|
|
Oxidative phosphorylation occurs in the _____ (mitochondria/cytoplasm).
|
mitochondria
|
|
What would an arterial blood gas show in pyruvate dehydrogenase deficiency?
|
Metabolic acidosis
|
|
What substance creates the metabolic acidosis in pyruvate dehydrogenase deficiency?
|
Patients have a lactic acidosis
|
|
Why is pyruvate dehydrogenase deficiency seen in alcoholics?
|
These individuals have a vitamin B1 deficiency, which is necessary to create active pyruvate dehydrogenase
|
|
True or False: A lack of active pyruvate dehydrogenase leads to the accumulation of pyruvate and alanine.
|
true
|
|
True or False: An alcoholic with decreased activity of the enzyme pyruvate dehydrogenase will have a normal neurological examination.
|
False; these individuals have neurologic deficits
|
|
A patient with pyruvate dehydrogenase deficiency should be given a diet high in _____ (ketogenic/glucogenic) amino acids.
|
ketogenic
|
|
What are the only two purely ketogenic amino acids?
|
lysine and leucine
|
|
In pyruvate metabolism, which enzyme catalyzes the conversion of pyruvate to alanine?
|
Alanine transaminase (ALT)
|
|
In pyruvate metabolism, which enzyme converts pyruvate to lactate?
|
Lactate dehydrogenase (LDH)
|
|
What enzyme converts pyruvate to acetyl-CoA?
|
pyruvate dehydrogenase complex (PDH)
|
|
In pyruvate metabolism, which enzyme catalyzes the conversion of pyruvate to oxaloacetate?
|
pyruvate carboxylase (PC)
|
|
Which amino acid serves as a carrier of amino groups from muscle to liver?
|
alanine
|
|
What are four compounds that can be formed from pyruvate?
|
Acetyl-CoA, lactate, alanine, and oxaloacetate
|
|
The conversion of pyruvate to lactate is the final step of which pathway?
|
Anaerobic glycolysis
|
|
Which cells in the body use anaerobic glycolysis as a major source of ATP?
|
RBCs, leukocytes, kidney medulla, testes, cornea and lens
|
|
Pyruvate can be converted to what substance used to replenish intermediates during the citric acid cycle?
|
Oxaloacetate; can also be used for gluconeogenesis
|
|
Pyruvate is converted into which two molecules that can enter the TCA cycle?
|
Acetyl-CoA and oxaloacetate
|
|
True or False: The Cori cycle transfers the metabolic burden of gluconeogenesis from RBCs and muscle to the liver.
|
true
|
|
What is the net gain or loss of ATP molecules during the Cori cycle?
|
There is a net loss of 4 ATP molecules
|
|
How many NADH molecules are produced during one turn of the citric acid cycle?
|
three
|
|
How many FADH2 molecules are produced during one turn of the citric acid cycle?
|
one
|
|
How many carbon dioxide molecules are produced during one turn of the citric acid cycle?
|
two
|
|
How many guanosine triphosphate molecules are produced during one turn of the citric acid cycle?
|
one
|
|
How many ATP molecules are produced during one turn of the citric acid cycle?
|
12 (3 * 3NADH + 1 * 2FADH2 + 1 GTP)
|
|
In the citric acid cycle, ATP _____ (activates/inhibits) citrate synthase.
|
inhibits
|
|
How many ATPs are produced from one acetyl-CoA molecule by the citric acid cycle?
|
12
|
|
In the citric acid cycle, ATP is an _____ (activator/inhibitor) of isocitrate dehydrogenase, whereas ADP is an _____ (activator/inhibitor).
|
inhibitor; activator (high vs low energy states)
|
|
How many ATP molecules are produced from one molecule of glucose by the citric acid cycle?
|
24
|
|
How many NADH molecules are produced from one molecule of glucose by the citric acid cycle?
|
6
|
|
How many FADH2 molecules are produced from one molecule of glucose by the citric acid cycle?
|
2
|
|
How many carbon dioxide molecules are produced from one molecule of glucose by the citric acid cycle?
|
4
|
|
How many guanosine triphosphate molecules are produced from one molecule of glucose by the citric acid cycle?
|
2
|
|
What enzyme of the citric acid cycle requires the same cofactors as pyruvate dehydrogenase complex?
|
The α-ketoglutarate dehydrogenase complex
|
|
The α-keoglutarate dehydrogenase complex requires which cofactors?
|
Pyrophosphate (B1), FAD (B2), NAD (B3), CoA (B5), and lipoic acid
|
|
In the citric acid cycle, α-ketoglutarate dehydrogenase is _____ (inhibited/activated) by the high-energy compounds NADH and ATP.
|
inhibited
|
|
In the citric acid cycle, ATP, acetyl-CoA, and NADH are _____ (inhibitors/activators) of pyruvate dehydrogenase.
|
inhibitors
|
|
What product provides negative feedback to α-ketoglutarate dehydrogenase to inhibit its function?
|
Succinyl-CoA
|
|
In the citric acid cycle, the production of α-ketoglutarate, succinyl-CoA, and oxaloacetate from their respective precursors produces what high-energy molecule?
|
NADH
|
|
Where in the cell does the TCA cycle take place?
|
The mitochondria
|
|
In the citric acid cycle, high-energy compounds such as ATP and NADH _____ (inhibit/activate) isocitrate dehydrogenase.
|
inhibit (isocitrate dehydrogenase is the rate limiting enzyme of the krebs/TCA cycle)
|
|
In the citric acid cycle, the reaction of pyruvate into acetyl-CoA is catalyzed by what enzyme?
|
Pyruvate dehydrogenase complex
|
|
What are the 5 cofactors required by the pyruvate dehydrogenase complex?
|
Vitamins B1 (thiamine for thiamine pyrophosphate -TPP), B2 (riboflavin for FADH2), B3 (niacin for NADH), and B5 (for CoA) and lipoic acid
|
|
In the citric acid cycle, the conversion of oxaloacetate to citrate is catalyzed by what enzyme?
|
citrate synthase
|
|
In the citric acid cycle, the conversion of isocitrate to α-ketoglutarate is catalyzed by what enzyme?
|
Isocitrate dehydrogenase
|
|
In the citric acid cycle, which enzyme catalyzes the conversion of α-ketoglutarate to succinyl-CoA?
|
The α-ketoglutarate dehydrogenase complex
|
|
Name the intermediates of the citric acid cycle.
|
Citrate, Isocitrate, α-Ketoglutarate, Succinyl-CoA, Succinate, Fumarate, Malate, and Oxaloacetate (mnemonic: Citrate Is Kreb's Starting Substrate For Making Oxaloacetate)
|
|
The formation what two substances during the citric acid cycle involve the release of carbon dioxide?
|
alpha-Ketoglutarate and succinyl-CoA
|
|
What step of the citric acid cycle produces guanosine triphosphate?
|
The conversion of succinyl-CoA into succinate
|
|
What step of the citric acid cycle produces FADH2?
|
The conversion of succinate into fumarate
|
|
True or False: The enzymes of the citric acid cycle are generally inhibited by high-energy compounds such as ATP or NADH.
|
true- feedback inhibition
|
|
True or False: The enzymes of the citric acid cycle are generally inhibited by low-energy compounds like adenosine diphosphate.
|
False; ADP is an activator
|
|
Name four enzymes in the TCA cycle whose actions are irreversible.
|
Pyruvate dehydrogenase, citrate synthase, isocitrate dehydrogenase, and α-ketoglutarate dehydrogenase
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Electrons carried by NADH from glycolysis may enter the mitochondria via which two shuttles?
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Malate-aspartate shuttle or glycerol-3-phosphate shuttle
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How many ATP molecules can be produced from one NADH molecule during oxidative phosphorylation?
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Three
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How many ATP molecules can be produced from one FADH2 molecule during oxidative phosphorylation?
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two
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Which complex in the electron transfer chain receives electrons carried by NADH?
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Complex I
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Which complex in the electron transfer chain receives electrons carried by FADH2?
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Complex II (succinate dehydrogenase)
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Why does FADH2 produce fewer molecules of ATP than NADH?
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It enters the electron transport chain at a lower energy level than NADH on complex II
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True or False: The electron transport chain creates an electron gradient which drives production of ATP.
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False; the electron transport chain creates a proton gradient, and this is used to form ATP
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What interacts with complex IV of the electron transport chain to drive oxidative phosphorylation forward?
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An oxygen molecule acts as the final electron acceptor in oxidative phosphorylation
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What is the mechanism of action by which oligomycin interrupts ATP production?
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Oligomycin directly inhibits mitochondrial ATPase
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How does the pesticide rotenone block ATP synthesis?
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Via direct inhibition of electron transport
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What happens to the proton gradient in the mitochondria when ATPase is inhibited by oligomycin?
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It increases, but protons cannot be released, causing the electron transport chain to halt and decreased ATP formation
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How does the drug antimycin A block ATP synthesis?
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Via direct inhibition of electron transport
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How does the poison cyanide block ATP synthesis?
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Via direct inhibition of electron transport
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How does the gas carbon monoxide block ATP synthesis?
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Via direct inhibition of electron transport
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Poisons that directly inhibit the electron transport chain lead to a(n) _____ (increased/decreased) proton gradient in the mitochondria.
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decreased
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what is the 5 year mortality rate of CHF
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50%
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How do rotenone, antimycin A, cyanide, and carbon monoxide all block oxidative phosphorylation, thus decreasing ATP synthesis?
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They are direct inhibitors of electron transport through the electron transport chain
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Regarding oxidative phosphorylation, name three examples of uncoupling agents that will block ATP production?
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2,4 DNP (dinitrophenol), aspirin, thermogenin
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True or False: Regarding oxidative phosphorylation, 2,4-dinitrophenol leads to decreased ATP synthesis, because it decreases the mitochondrial proton gradient.
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true- via uncoupling
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Regarding oxidative phosphorylation, direct ATPase inhibitors like oligomycin _____ (increase/decrease) the proton gradient.
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increase
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Regarding oxidative phosphorylation, the administration of 2,4-dinitrophenol leads to the _____ (cessation/continuation) of electron transport but the _____ (cessation/continuation) of ATP production.
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continuation; cessation
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Regarding oxidative phosphorylation, 2,4-dinitrophenol _____ (increases/decreases) oxygen consumption.
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increases
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Regarding oxidative phosphorylation, 2,4-dinitrophenylhydrazine _____ (increases/decreases) the permeability of the mitochondrial membrane.
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increases
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Regarding oxidative phosphorylation, electron transport inhibitors _____ (increase/decrease) the proton gradient.
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decrease
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Regarding oxidative phosphorylation, 2,4-dinitrophenol _____ (increases/decreases) the proton gradient.
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decreases-- it is an uncoupler
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When acting as an uncoupling agent, aspirin _____ (increases/decreases) the proton gradient in the mitochondria.
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decreases
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Thermogenin in brown fat _____ (increases/decreases) oxygen consumption during oxidative phosphorylation.
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increases-- uncoupler
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What is the action of an uncoupling agent on the mitochondrial membrane?
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These increase the permeability of the membrane, decreasing the proton gradient
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Why does ATP production decrease when the mitochondrial membrane is disturbed?
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The loss of the proton gradient means that there is nothing to drive the ATPase reaction
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Does disruption of the proton gradient by an uncoupling agent cause electron transport to stop?
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No; electron transport continues, but the protons moved across the membrane are free to return down the gradient without producing ATP
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What is the result of an uncoupling agent on mitochondrial oxygen consumption?
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There is increased oxygen consumption, because electron transport continues in an attempt to maintain the proton gradient
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Name two mechanisms where ATP synthesis is inhibited and there is a decreased proton gradient across the inner mitochondrial membrane.
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This occurs with electron transport inhibitors and uncoupling agents
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To produce ATP, protons must flow down their gradient from the _____ _____ across the inner mitochondrial membrane to the _____ _____.
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Intermembranous space; mitochondrial matrix
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Name two mechanisms in which oxidative phosphorylation is inhibited and electron transport stops.
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This occurs with electron transport inhibitors and ATPase inhibitors
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In gluconeogenesis, what reaction is catalyzed by pyruvate carboxylase?
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The conversion of pyruvate into oxaloacetate
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In gluconeogenesis, is pyruvate carboxylase found in the mitochondria or in the cytosol?
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The mitochondria
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_____ (Gluconeognesis/Glycolysis) requires the catalyzation of pyruvate to oxaloacetate by pyruvate carboxylase.
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gluconeogenesis
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In gluconeogenesis, is phosphoenolpyruvate carboxykinase found in the mitochondria or in the cytosol?
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The cytosol
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In gluconeogenesis, what enzyme catalyzes the conversion of oxaloacetate into phosphoenolpyruvate?
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Phosphoenolpyruvate carboxykinase
(PEP carboxykinase) |
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In gluconeogenesis, is fructose-1,6-bisphosphatase found in the mitochondria or in the cytosol?
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The cytosol
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In gluconeogenesis, what is the name of the enzyme that catalyzes the reaction of fructose-1,6-bisphosphate to fructose-6-phosphate?
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Fructose-1,6-bisphosphatase
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In gluconeogenesis, is glucose-6-phosphatase found in the mitochondria or in the cytosol?
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The cytosol
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In gluconeogenesis, does phosphoenolpyruvate carboxykinase require ATP or GTP for activity?
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GTP
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True or False: Gluconeogenesis occurs in skeletal muscle.
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False; muscle does not contain the enzymes needed for gluconeogenesis
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_____ (Odd/Even)-chain fatty acids yield propionyl-CoA during metabolism, which can produce new glucose; while _____ (odd/even)-chain fatty acids yield acetyl-CoA equivalents.
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odd chain; even chain (acetyl CoA cannot go onto to form glucose)
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In gluconeogenesis, what reaction is catalyzed by glucose-6-phosphatase?
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The conversion of glucose-6-phosphate into glucose
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True or False: The irreversible enzymes of gluconeogenesis are found only in the liver, the kidney, and the intestinal epithelium.
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true
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A deficiency of the key gluconeogenic enzymes that catalyze irreversible reactions leads to what condition?
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hypoglycemia
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_____ (Odd/Even) -chain fatty acids yield propionyl-CoA during metabolism, which can enter the citric acid cycle, undergo gluconeogensis, and serve as a glucose source.
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odd
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Which cofactors are required by the enzyme pyruvate carboxylase?
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Biotin and ATP
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Glucose-6-phosphatase is found in which cellular organelle?
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The endoplasmic reticulum
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Name four enzymes in gluconeogenesis whose actions are irreversible.
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Pyruvate carboxylase, PEP carboxykinase, Fructose-1,6-bisphosphatase, Glucose-6-phosphatase (remember: Pathway Produces Fresh Glucose)
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What is an expected presenting symptom of von Gierke's disease, which is a deficiency of glucose-6-phosphatase in the liver?
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Severe hypoglycemia due to the lack of gluconeogenesis
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What is the primary location of gluconeogenesis in the body?
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liver
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Which small molecule can produce glucose after fatty acid metabolism: acetyl-CoA or propionyl-CoA?
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propionyl-CoA--enters TCA cycle as succinyl CoA
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What product of the pentose phosphate pathway (HMP shunt) facilitates steroid and fatty acid synthesis?
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NADPH
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What is the function of NADPH in the erythrocyte?
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It reduces glutathione-which deals with oxidative stress from H2O2
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What are the two phases of the HMP shunt (pentose phosphate pathway)?
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There is an initial oxidative phase and a second nonoxidative phase
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What key enzyme regulates the oxidative phase of the HMP shunt?
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Glucose-6-phosphate dehydrogenase
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What vitamin is required for the nonoxidative phase of the HMP shunt?
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The transketolases that catalyze the nonoxidative reactions require thiamine (vitamin B1) as a cofactor
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What four products are formed after both phases of the HMP shunt?
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Ribose-5-phosphate, G3P, F6P, and NADPH are the products
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Which product of the HMP shunt is then used in nucleotide synthesis?
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Ribose-5-phosphate
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How are G3P and F6P utilized in the cell following the HMP shunt?
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These are glycolytic intermediates and can enter glycolysis
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The oxidative phase of the HMP shunt is _____ (reversible/irreversible), while the nonoxidative phase is ______. (reversible/irreversible).
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Irreversible; reversible
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Name three sites of fatty acid or steroid synthesis that would show high pentose phosphate pathway (HMP shunt) activity.
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Lactating mammary glands, liver, adrenal cortex
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Do the reactions of the hexose monophosphate shunt (pentose phosphate pathway) take place in the mitochondria or the cytosol of a cell?
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cytosol
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True or False: The hexose monophosphate shunt (pentose phosphate pathway) neither consumes nor produces ATP.
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true
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Where would you find elevated activity of the pentose phosphate pathway, but no fatty acid or steroid synthesis?
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In the RBC, to reduce glutathione; remember, the RBC has no organelles
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Name two cells that utilize NADPH for an oxidative burst.
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Neutrophils, macrophages
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Why would you expect cells like neutrophils and macrophages to have high concentrations of NADPH oxidase?
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This is important for the innate immune response, rapidly releasing reactive oxygen species
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During the oxygen-dependent respiratory burst used by neutrophils to destroy bacteria, what enzyme converts hydrogen peroxide to bleach (hypochlorite) in the presence of chloride ion?
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Myeloperoxidase, which is found in neutrophil azurophilic granules
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During the oxygen-dependent respiratory burst that is used by neutrophils to destroy bacteria, what enzyme converts oxygen to superoxide?
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NADPH oxidase
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Regarding the neutrophil oxygen-dependent respiratory burst, is glutathione reduced or oxidized when converting hydrogen peroxide to water?
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oxidized
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What disease is caused by a deficiency of NADPH oxidase?
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Chronic granulomatous disease
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Regarding the neutrophil oxygen-dependent respiratory burst, which electron carrier is used to reduce glutathione after the conversion of hydrogen peroxide to water?
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NADPH from the HMP shunt
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During the oxygen-dependent respiratory burst that is used by neutrophils to destroy bacteria, what enzyme converts superoxide to hydrogen peroxide?
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Superoxide dismutase
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Which form of glutathione must be readily available in the cell to remove reactive oxygen species to prevent cell lysis?
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The reduced form (GSH)
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During the oxygen-dependent respiratory burst that is used by neutrophils to destroy bacteria, what enzyme converts hydrogen peroxide to water in the presence of glutathione?
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catalase
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During the oxygen-dependent respiratory burst that is used by neutrophils to destroy bacteria, which enzyme converts glutathione from its reduced state (GSH) to its oxidized state (GSSG)?
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Glutathione peroxidase
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What enzyme uses NADPH to replenish reduced glutathione?
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Glutathione reductase
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True or False: The pentose phosphate pathway shunt produces NADPH.
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true
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What enzyme replenishes the NADPH used to reduce glutathione?
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Glucose-6-phosphate dehydrogenase
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What is the end product of the oxygen-dependent respiratory burst that is used to kill extracellular bacteria in the phagolysosome?
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Bleach (HOCl, hypochlorite)
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