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54 Cards in this Set
- Front
- Back
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Competitive inhibitors have this effect |
This type of inhibitor both changes the Km and interferes with substrate binding |
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The value of Vmax changes in |
noncompetitive inhibition |
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A noncompetitive inhibitor |
binds to the enzyme at a site other than the active site |
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What effect is seen on a Lineweaver-Burk graph when a mixed-type inhibitor is added? |
Both the y-intercept and the slope of the line are changed |
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The saturation curve for aspartyl transcarbamylase has a similar shape to the curve for: |
hemoglobin |
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CTP is a known inhibitor of ATCase, the enzyme that catalyzes the first reaction in the pathway for the synthesis of this compound. This is an example of |
feedback inhibition |
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Which of the following is a mechanism of regulating enzyme activity? |
Feedback inhibition by product Presence of activators Addition or removal of phosphate groups from of the enzyme Activation of zymogens All |
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Which of the following is not required in order for an enzyme to display cooperative kinetics? |
A value for the Michaelis constant, Km |
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A velocity curve (V vs. [S]) for a typical allosteric enzyme will be |
a sigmoid curve |
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Kinase relations describe enzymes which |
add phosphate groups to another molecule |
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Zymogens are |
inactive precursors of enzymes which can be activated by the irreversible cleavage of covalent bonds |
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The critical serine residue in the active site of chymotrypsin functions as |
a nucleophile |
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Important mechanisms of enzymatic catalysis include |
general acid-base catalysis nucleophilic reactions Lewis acid-base catalysis All |
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Abzymes |
are antibodies with catalytic activity |
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Cofactors are |
non-protein in chemical nature |
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What does amphipathic mean? |
having both hydrophilic and hydrophobic regions |
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Which of the following is true? |
Fatty acids with an odd number of carbons are more rare than those with an even number |
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What kinds of bonds do lipase break in order to release fatty acids form triacylglycerols? |
Esters |
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Which of the following groups is not present in a cerebroside? |
Phosphate |
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Which of the following lipids is not found in biological membranes? |
triacylglycerols |
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Which of the following groups is not present in sphingomyelin? |
Sugar
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Which of the following four fatty acids has the highest melting point
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2 (the largest chain) |
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The myelin sheaths of neurons typically contain large amounts of |
sphingolipids |
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Biological waxes are composed of |
a fatty acid and a long-chain alcohol |
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Which of the following cell types contains cholesterol? |
animal |
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Membrane lipids in a lipid bilayer are held together by |
hydrophobic interactions |
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the degree of membrane fluidity depends on |
the percentage of unsaturated fatty acids |
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Which property has not been observed for membrane proteins? |
energy storage |
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Liposomes are |
artificial membrane-bonded structures used to deliver medications |
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The difference between active transport and passive transport is that |
one requires expenditure of energy by the cell and the other does not |
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A major difficulty in extracting receptor proteins form membranes is that |
there may be very few molecules of the protein in a cell it is difficult to remove the proteins form the membrane without denaturation receptor proteins tend to have high molecular weights All |
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In the sodium-potassium pump |
Sodium is transported out of the cell and potassium into the cell, both against concentration gradients |
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The vitamin classified as fat soluble rather than water soluble is |
Vitamin A |
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The nucleotide sequence of DNA is which level of structure? |
primary |
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What distinguishes nucleotides form nucleosides? |
Nucleosides lack the phosphate group |
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Which of the following nucleases is a purine? |
Adenine |
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Which best describes the relationship between the nucleopbases in a piece of DNA? |
They are perpendicular to the helical axis |
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Which is the dominant form of DNA found in the cell? |
B |
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Histones contain large amounts of which of the following amino acids? |
lysine |
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The A and B forms of DNA |
are both right-handed helices |
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Topoisomerase's are associated with |
supercoiling of DNA |
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The Tm for melting the double helix is: |
The midpoint of the range over which the helix denatures |
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Eukaryotic mRNA requires |
more processing after synthesis than prokaryotic mRNA |
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The production of RNA on a DNA template is called |
transcription |
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The flow of genetic information is RNA --> DNA in |
retroviruses |
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What is the requirement for a template strand in DNA replication? |
It serves as a guide in determining the next nucleotide to be added according to Watson-Crick base pairing scheme |
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In the original Central Dogma of biology, the ordinary flow of genetic information is: |
DNA-->RNA-->Protein |
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The primer for in vivo DNA replication is: |
A short piece of RNA |
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(Graph) Which diagram correctly depicts the orientation of the lagging and leading strands on the parentals? |
The bottom |
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What is the need for a primer strand in DNA replication? |
the DNA polymerases require a preexisting strand with a nucleotide having a 3'-OH |
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Which of these proteins is used less for leading strand replication than for lagging strand replication? |
DNA ligase
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The enzyme that attaches the Okazaki fragments together is called |
ligase |
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Eukaryotes need more types of DNA polymerases than bacteria because |
the DNA-containing organelles have their own DNA plymerases |
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Telomerase activity may decline with old age and this could explain why cells lose their ability to divide after many replications |
True |
