Usmle Biochem

Front 1

cystinuria is a defect of which aa transporter?

Back 1

positively charged aas--> cysteine, ornithine, lysine, arginine

Front 2

cystinuria - where is the transporter located that is defective?

Back 2

proximal convoluted tubule of kidney

Front 3

What are two signs of cystinuria?

Back 3

cystinuria and cysteine kidney stones

Front 4

What's the inheritance pattern for cystinuria?

Back 4

autosomal recessive

Front 5

What's the treatment for cystinuria?

Back 5

acetazolamide to alkalinize the urine

Front 6

In cystinuria, how would stones be described?

Back 6

yellow-brown, hexagonal morphology

Front 7

homocysteinuria- what enzyme is deficient (2)?

Back 7

homocysteine methyltransferase or cystathionine synthase

Front 8

What is a way you can get homocysteinuria besides having an enzyme deficiency?

Back 8

cystathionine synthase could have decreased affinity for B6

Front 9

Draw the pathway for how you get from methionine --> cysteine

Back 9

see FA

Front 10

increased homocysteine in urine, MR, osteoporosis, tall stature, kyphosis, lens subluxation, atherosclerosis (MI, etc). Dx?

Back 10

homocysteinuria

Front 11

Does purine synthesis start with base or sugar?

Back 11

sugar

Front 12

What is the rate-limiting enzyme of purine synthesis?

Back 12

Glu-PRPP amidotransferase

Front 13

Where does 6MP act?

Back 13

Inhibits PRPP synthetase (purine synthesis)

Front 14

Where does mycophenolic acid act?

Back 14

Blocks IMP --> GMP (enzyme is inosine monophosphate dehydrogenase), purine synthesis

Front 15

Describe how SCID related to adenosine deaminase deficiency works.

Back 15

Adenosine deaminase is needed to break down adenosine --> inosine which then goes to hypoxanthine.
You can't break down ATP/dATP so it feedback inhibits ribonucleotide reductase and leads to decreased DNA synthesis and lymphocyte count

Front 16

How does UV light damage DNA?

Back 16

pairs thymine to thymine on same strand

Front 17

What does DNA helicase do?

Back 17

unwinds DNA

Front 18

What does DNA topoisomerase do?

Back 18

relieves supercoils

Front 19

What antibiotic inhibits prokaryote topoisomerase?

Back 19

fluoroquinonlones

Front 20

Name a fluoroquinonlone

Back 20

ciprofloxacin, norfloxacin, ofloxacin, sparfloxacin, moxifloxacin, gatifloxacin, enoxacin

Front 21

What does prokaryotic DNA pol III do?

Back 21

elongates leading strand by adding nucleotides to 3' end and elongates lagging strand til it reaches the primer of the preceding fragment

Front 22

What does prokaryotic DNA pol I do?

Back 22

degrades primer and fills in gap with DNA

Front 23

What type of DNA repair goes wrong in xeroderma pigmentosum?

Back 23

nucleotide excision repair

Front 24

What are signs/symptoms of xeroderma pigmentosum?

Back 24

dry skin with melanoma and other cancers (like basal cell carcinoma)

Front 25

Name 4 diseases that are from DNA repair defects:

Back 25

ataxia telangiectasia, bloom's syndrome, HNPCC, BRCA1/BRCA2

Front 26

For each type or RNA (r, m, t), say one characteristic

Back 26

r- most abundant (rampant), m- massive (longest), t- smallest (tiny)

Front 27

Which type of RNA pol makes which type of RNA?

Back 27

rRNA- pol I, mRNA- pol II, tRNA pol III

Front 28

What is the mRNA start codon?

Back 28

AUG

Front 29

What does mRNA start codon code for in eukaryotes?

Back 29

methionine

Front 30

What are the 3 mRNA stop codons?

Back 30

UGA, UAA, UAG

Front 31

Describe where ATP and GTP are needed in translation.

Back 31

ATP- needed to charge tRNA

GTP- needed to add charged tRNA to A-site and translocation

Front 32

Which antibiotic class inhibits the 50s peptidyl transferase (2)?

Back 32

chloramphenicol and streptogramins

Front 33

Which antibiotic classes bind 50s and block translocation?

Back 33

macrolides, clindamycin, linazolid

Front 34

Where are ribosomes synthesized?

Back 34

in the nucleus

Front 35

Name 3 degradation mechanisms for proteins.

Back 35

ubiquitinylation (proteasomal)
lysosomal degradation
Ca2+ dependent enzymes

Front 36

How many ATPs per NADH?

Back 36

3

Front 37

How many ATPs per FADH2?

Back 37

2

Front 38

How many ATPs per glucose?

Back 38

24 from TCA cycle + 12 (or 14) from glycolysis

Front 39

Where does TCA cycle occur?

Back 39

mitochondria

Front 40

Name the TCA intermediates in order

Back 40

citrate --> isocitrate --> alpha-ketoglutarate --> succinyl coA --> succinate --> fumarate --> malate --> OAA

(can remember Citrate Is Krebs' Starting Substrate For Making OAA)

Front 41

What are the cofactors required for alpha-ketoglutarate dehydrogenase?

Back 41

thiamine (B1), lipoic acid, CoA (B5), FAD (B2), NADH (B3)

Front 42

Which proteins can you not synthesize in abetalipoproteinemia?

Back 42

Apo B 100 (VLDL secretion), Apo B48 (chylomicron secretion)

Front 43

Where do lipids accumulate in abetalipoproteinemia?

Back 43

In enterocytes

Front 44

What are the physical findings in abetalipoproteinemia?

Back 44

failure to thrive, steatorrhea, acanthocytosis, ataxia, night blindness

Front 45

Treatment for abetalipoproteinemia?

Back 45

Vitamin E

Front 46

Familial hypercholesterolemia:
Cholesterol levels in homozygotes and heterozygotes?

Back 46

Homo-700+ mg/dL, hetero- ~300 mg/dL

Front 47

Familial hypercholesterolemia:
Complications?

Back 47

atherosclerotic disease, tendon xanthomas, MI

Front 48

Familial hypercholesterolemia:
Where do xanthomas tend to form?

Back 48

achilles

Front 49

Familial hypercholesterolemia:
Inheritence pattern?

Back 49

autosomal dominant

Front 50

Hyperchylomicronemia:
What is elevated?

Back 50

TG (very) and cholesterol (less so)

Front 51

Hyperchylomicronemia:
What are the sequelae?

Back 51

pancreatitis, hepatosplenomegaly, xanthomas
NOT athero

Front 52

What is elevated in hypertriglyceridemia?

Back 52

TGs only

Front 53

What are the sequelae of hypertriglyceridemia?

Back 53

pancreatitis

Front 54

What 3 aas are needed for purine synthesis?

Back 54

glycine, aspartate, glutamine

Front 55

What are the sources of carbon for purine molecules?

Back 55

CO2, TH4 (FOLATE), glycine

Front 56

What substances are needed to make pyrimidines?

Back 56

glutamine + CO2 --> carbamoyl phosphate
+
aspartate, glutamine, TH4

Front 57

What substances provide the carbons in pyrimidine?

Back 57

aspartate, CO2

Front 58

Do you start with sugar or base for purine synthesis?

Back 58

Sugar (think PURE SUGAR)

Front 59

Do you start with sugar or base for pyrimdine synthesis?

Back 59

base

Front 60

What's the rate-limiting enzyme for pyrimidine synthesis?

Back 60

carbamoyl phosphate synthase II

Front 61

Where does hydroxyurea act?

Back 61

blocks ribonucleotide reductase (pyrimidine synthesis)

Front 62

Where does 5 FU act?

Back 62

blocks thymidylate synthase; pyrimidine synthesis

Front 63

Where does methotrexate act?

Back 63

blocks dihidrofolate reductase which is needed to go from DHF to THF , which is then turned into N5,N10 methylene THF and needed for pyrimidine synthesis

Front 64

What is the equivalent of methotrexate for bacteria?

Back 64

trimethoprim

Front 65

less condensed chromatin is called?

Back 65

euchromatin

Front 66

Name the purines

Back 66

Guanine, adenine

Front 67

Pyrimidines are (names)

Back 67

cytosine, thymidine, uracil

Front 68

chemical group on guanine?

Back 68

ketone

Front 69

what reaction changes cytosine --> uracil?

Back 69

deamination

Front 70

What's the chemical group on thymine?

Back 70

methyl

Front 71

G forms hydrogen bonds with which base?
How many?

Back 71

C
3

Front 72

A forms H bonds with which base?
How many?

Back 72

T
2

Front 73

Base + ribose is called?

Back 73

nucleoside

Front 74

Base + ribose + phosphate is called?

Back 74

nucleotide

Front 75

Duchenne's/Becker's muscular dystrophy:
Inheritence?

Back 75

x-linked recessive

Front 76

What gene is affected in Duchenne/Becker's?

Back 76

dystrophin

Front 77

Duchenne/Beckers:
What is the molecular different between the two?

Back 77

In Duchenne, dystrophin gene is deleted; in Becker's, it's mutated (more mild phenotype)

Front 78

What does dystrophin do?

Back 78

helps anchor muscle fibers, especially in skeletal and cardiac muscle

Front 79

How do you diagnose Duchenne/Beckers?

Back 79

Increased CPK + muscle biopsy

Front 80

What are the physical findings in Duchenne/Beckers?

Back 80

pseudohypertrophy of calf muscles, Gowers maneuver (using upper extremities to help stand up)

Front 81

Neurofibromatosis Type 1: physical findings

Back 81

neurofibroma (brain), schwannoma, optic nerve glioma, hamartoma of the iris (aka Lish nodule), cafe au lait spots, and skeletal (scoliosis/kyphosis)

Front 82

NF1 is also called?

Back 82

von Recklinghausen's disease

Front 83

NF type 1 is found on what chromosome?

Back 83

Chromosome 17

Front 84

NF 2- gene and chromosome

Back 84

NF2 gene on chromosome 22

Front 85

NF2 findings (two)

Back 85

bilateral acoustic schwannomas, juvenile cataracts

Front 86

Tuberous Sclerosis:
Findings?

Back 86

Cortical tubers (hamartomas), seizures, MR, astrocytomas, retinal hamartomas, ash leaf spots, angiofibromas (adenoma sebaceum on face), rhabdomyoma, renal angiomyolipomas

Front 87

Tuberous Sclerosis:
What genetic concept is demonstrated?

Back 87

Incomplete penetrance, variable presentation

Front 88

Von Hippel Lindau:
Associated tumors

Back 88

hemangioblastomas of retina/cerebellum/medulla, multiple bilateral renal cell carcinomas, pheochromocytomas

Front 89

Von Hippel Lindau:
What does the gene deletion lead to?

Back 89

constituitive expression of HIF transcription factor --> activation of angiogenic growth factors

Front 90

What two drugs are metabolized by XO?

Back 90

6MP/azathioprine

Front 91

What happens when you give azathioprine/6MP + allopurinol?

Back 91

The first drug is too strong bc XO is blocked and can't metabolize it

Front 92

Enzyme HGPRT catalyzes what reaction?

Back 92

Guanine or hypoxanthine (base w/ no sugar or phosphate) --> GMP or IMP (nucleotide +sugar, + phosphate)

Front 93

What are the findings in Lesch Nyhan syndrome?

Back 93

hyperuricemia, gout, aggression, self-mutilation, choreoathetosis (involuntary movements)

Front 94

What is the inheritance pattern of Lesch Nyhan syndrome?

Back 94

x-linked recessive

Front 95

Familial Adenomatous Polyposis:
Chromosome & gene that's mutated

Back 95

APC gene on chromosome 5

Front 96

Familial Adenomatous Polyposis:
Name two other diseases (besides FAP) that have APC gene mutations

Back 96

Turncott's and Gardiner's syndrome

Front 97

Autosomal Dominant Polycystic kidney disease:
What do kidneys look like?

Back 97

bilateral, massive enlargement, multiple large cysts

Front 98

Autosomal Dominant Polycystic kidney disease:
How does disease present?

Back 98

flank pain, hematuria, hypertension, renal failure

Front 99

Autosomal Dominant Polycystic kidney disease:
90% of cases due to mutation in ?

Back 99

ADPKD1 gene

Front 100

Autosomal Dominant Polycystic kidney disease:
Other pathology associated with ADPKD (3)?

Back 100

polycystic liver disease, berry aneurysms, and mitral valve prolapse

Front 101

Achondroplasia:
Due to defect in ?

Back 101

FGF receptor 3

Front 102

Achondroplasia:
Inheritance?

Back 102

autosomal dominant

Front 103

Hereditary Hemorrhagic Telangiectasia:
What is it also called?

Back 103

Oscar-weber-rendu syndrome

Front 104

Hereditary Hemorrhagic Telangiectasia:
Name 4 findings

Back 104

telangiectasia, recurrent epistaxis, skin discolorations, arteriovenous malformations

Front 105

Hereditary Hemorrhagic Telangiectasia:
Inheritance?

Back 105

Autosomal dominant

Front 106

Hereditary Spherocytosis:
What is the genetic defect?

Back 106

Problem with spectrin/ankyrin

Front 107

Hereditary Spherocytosis:
Presentation

Back 107

spherocytes, hemolytic anemia, increased MCHC

Front 108

Hereditary Spherocytosis:
Treatment?

Back 108

splenectomy

Front 109

Hereditary Spherocytosis:
diagnosis?

Back 109

osmotic fragility test

Front 110

Hereditary Spherocytosis:
inheritance?

Back 110

autosomal dominant

Front 111

Edwards Syndrome:
What would you see on quad screen?

Back 111

decreased betaHCG, dec. AFP, dec. estriol

Front 112

Edwards Syndrome:
Findings

Back 112

severe MR, rocker-bottom feet, micrognathia, low-set ears, clenched hands, prominent occiput

Front 113

Patau Syndrome:
Findings

Back 113

severe MR, rocker-bottom feet, microcephatly, microophthalmia, cleft lip/palate, holoprosencephaly, polydactyly

Front 114

What findings are unique to Edwards syndrome?

Back 114

micrognathia, clenched hands

Front 115

What sx are unique to Patau syndrome?

Back 115

cleft lip, holoprosencephaly, polydactyly

Front 116

22q11 deletion syndromes (general):
Findings

Back 116

cleft palate, abnormal facies, thymic aplasia, cardiac defects, HYPOCALCEMIA

Front 117

Findings specifically in diGeorge syndrome?

Back 117

thymic, parathyroid, and cardiac defects

Front 118

Findings specifically in velocardiofacial syndrome?

Back 118

palate, facial, cardiac

Front 119

22q11 deletion syndromes:
Due to aberrant development of?

Back 119

3rd and 4th branchial pouches

Front 120

NAD associated with which vitamin?

Back 120

Niacin (B3)

Front 121

FAD associated with which vitamin?

Back 121

Riboflavin (B2)

Front 122

Describe enzyme & sx:
Essential fructosuria

Back 122

Enzyme- fructokinase
Sx- asymptomatic but fructose appears in blood and urine

Front 123

Describe enzyme & sx:
Fructose intolerance

Back 123

Enzyme- aldolase B
Sx- end up with inc. fructose 1-P and less free phosphate --> hypoglycemia, jaundice, cirrhosis, vomiting

Front 124

Treatment for fructose intolerance?

Back 124

decrease intake of fructose & sucrose (glucose + fructose)

Front 125

What drug inhibits alcohol --> acetaldehyde?

Back 125

fomepizole

Front 126

What drug inhibits acetaldehyde --> acetate?

Back 126

disulfiram

Front 127

An end product of alcohol metabolism is acetyl co-A. Name two things acetyl-co A can be made into.

Back 127

1) ketone bodies
2) fatty acids

Front 128

Describe how alcohol inhibits gluconeogenesis.

Back 128

Because NADH is a cofactor to change OAA to malate, which stops OAA --> PEP --> glucose via gluconeogenesis

Front 129

Pyruvate dehydrogenase deficiency would lead to what symptoms?

Back 129

lactic acidosis, neurologic defects

Front 130

What is the treatment for pyruvate dehydrogenase deficiency?

Back 130

increase ketogenic foods bc that will bypass pyruvate dehydrogenase and enter the TCA cycle later

Front 131

Give examples of ketogenic nutrients (what do they contain?)

Back 131

high in fat, lysine, leusine

Front 132

How many pyruvates / glucose metabolized?

Back 132

2

Front 133

Two things that activate PFK-1

Back 133

AMP, fructose 2,6, BP

Front 134

Two things that inhibit PFK-1

Back 134

ATP, citrate

Front 135

PEP --> pyruvate (enzyme?)

Back 135

pyruvate kinase

Front 136

What increases action of pyruvate kinase?

Back 136

fructose 1,6 BP

Front 137

What decreases action of pyruvate kinase (2 things)?

Back 137

ATP, alanine

Front 138

Draw out how PRK 1 regulation works

Back 138

See FA p. 98

Front 139

Which enzyme to convert glucose to G6P is only in liver/ beta cells of pancreas?

Back 139

glucokinase

Front 140

Which enzyme to convert glucose to G6P is ubiquitous?

Back 140

hexokinase

Front 141

Which enzyme that converts glucose to G6P has high affinity?

Back 141

hexokinase

Front 142

Which enzyme that converts glucose to G6P is induced by insulin?

Back 142

glucokinase (bc you want liver to make glycogen w. the glucose)

Front 143

Which enzyme that converts glucose to G6P has a high vmax?

Back 143

glucokinase (is a GLUTTON)

Front 144

What's the most common human enzyme deficiency?

Back 144

G6PD deficiency

Front 145

Two associated RBC pathologies with G6PD deficiency?

Back 145

bite cells, heinz bodies

Front 146

Name the drugs that cause oxidative damage.

Back 146

FIND SPAIN

F- fava beans, I- isoniazid, N-naphthalin, D-dapsone, S-sulfonamide, P-primaquine, A-aspirin, I-ibuprofinm, N-nitrofurantoin

Front 147

Name an enzyme deficiency aside from G6PD that causes RBC lysis.

Back 147

pyrvuate kinase deficiency

Front 148

What's the rate limiting enzyme of gluconeogenesis?

Back 148

fructose 1,6, bisphosphatase

Front 149

In gluconeogenesis, from pyruvate, where do you do and what's the cofactor?

Back 149

pyruvate --> OAA, pyruvate carboxylase, cofactor is biotin

Front 150

Fructose 1, 6, BP --> fructose 6 P is catalyzed by?

Back 150

fructose 1, 6 bisphosphatase

Front 151

Fructose 1, 6, bisphosphatase is the opposite of which enzyme in glycolysis?

Back 151

PFK-1

Front 152

What enzyme catalyzes G6P --> glucose?

Back 152

glucose 6 phosphatase

Front 153

Why do only odd-chain fatty acids net glucose when they enter the TCA cycle?

Back 153

Because acetyl-coA is a breakdown product of even chain fatty acids, and when acetyl coA enters TCA cycle, first step is to add OAA, which leads to lost CO2 and thus you don't actually keep the carbon you are putting into the cycle

Front 154

Name three causes of cherry-red spot on macula

Back 154

- Tay Sachs, Niemann Pick, and central retinal artery occlusion

Front 155

5% of Down syndrome cases are due to two genetic phenomenae... what are they?

Back 155

1) robertsonian translocation (4%)
2) down mosaicism (1%)

Front 156

What chromosome is affected in cri du chat?

Back 156

5

Front 157

What chromosome is affected in Williams syndrome?

Back 157

7

Front 158

Findings in Williams syndrome?

Back 158

well-developed verbal skills, MR, hypercalcemia, elfin facies, extreme friendliness w/ strangers, heart problems

Front 159

Glycogen Synthesis-
1) Rate limiting enzyme
2) What type of linkage is the linear?
3) What kind of linkage is the branch?

Back 159

1) glycogen synthase
2) alpha 1,4
3) alpha 1,6

Front 160

Describe the impact (molecular) and the name of the associated disease:
1) glucose 6 phosphatase
2) Lysosomal alpha 1,4 glucosidase
3) Debranching enzyme
4) skeletal muscle glycogen phosphorylase

Back 160

1) can't turn glycogen back into glucose and can't complete glycolysis- Von Gierke
2) can't break down glycogen in lysosomes; Pompe's disease
3) Can't break branches down (once there are four glucoses left), Cori's disease
4) can't break down glycogen in muscle; McArdle's disease

Front 161

Glycogenolysis:
1) Rate-limiting enzyme

Back 161

1) glycogen phosphorylase

Front 162

Name the glycogen storage disease with these findings:
1) muscle cramps, myoglobinurea with exercise
2) cardiomegaly, systemic findings
3) mild, normal blood lactate levels
4) severe hypoglycemia (fasting), highly increased liver glycogen, increased blood lactate, hepatomegaly

Back 162

1) McArdles
2) Pompe's
3) Cori's
4) Von Gierke's

Front 163

What do you get lactic acidosis in Von Gierke's disease?

Back 163

Because you can't complete gluconeogenesis so you do more glycolysis and some of that goes to lactate

Front 164

In which glycogen storage disease do you normally see death by age 3?

Back 164

Pompe's disease

Front 165

Ocular albinism genetics?

Back 165

x-linked recessive

Front 166

Wiskott-Aldrich syndrome genetics?

Back 166

x-linked recessive

Front 167

HMP Shunt:
1) Rate limiting enzyme
2) Name two important HMP intermediates

Back 167

1) G6PD
2) NADPH, ribulose 5 phosphate (used in purine synth)

Front 168

Name at least 4 processes where NADPH is used

Back 168

steroid/fatty acid synthesis, respiratory burst, glutathione reductase, p-450

Front 169

How many ATPs are used in HMP shunt?

Back 169

0

Front 170

How is NADPH used to generate respiratory burst?

Back 170

It's a cofactor for NADPH oxidase to turn O2 into oxygen free radical

Front 171

Describe the changes (enzymes and intermediates) to go from O2 --> HOCl.

Back 171

See FA p. 102

Front 172

How is NADPH used to help protect cells from oxidative damage?

Back 172

NADPH reduces glutathione and reduced glutathione accepts oxygen from H2O2 to form H2O

Front 173

What is the job of apoprotein A-1?

Back 173

activates LCAT

Front 174

What is the job of apoprotein B100?

Back 174

binds LDL receptor, mediates VLDL secretion (from liver)

Front 175

What is the job of apoprotein C-II?

Back 175

cofactor for lipoprotein lipase

Front 176

What is the job of Apo B-48?

Back 176

mediates chylomicron secretion

Front 177

What is the job of apoprotein E?

Back 177

mediates extra remnant uptake

Front 178

What are the symptoms of ammonia intoxication?

Back 178

tremor (asterixis), slurring of speech, somnolence, vomiting, cerebral edema, blurred vision

Front 179

What is the treatment for ammonia toxicity (due to urea cycle disorders)

Back 179

benzoate or phenylbutyrate + less protein in diet

Front 180

Tx for ammonia toxicity due to liver failure?

Back 180

lactulose

Front 181

What is mechanism of action of lactulose to treat ammonia toxicity secondary to liver failure?

Back 181

creates acidic environment in colon and draws NH4+ to it (osmotic diarrhea)

Front 182

What receptor does liver use to take up chylomicron remnants?

Back 182

LRP - LDL receptor protein

Front 183

What two forms of lipoproteins are released from the liver?

Back 183

VLDL, HDL

Front 184

What enzyme transfers cholesterol from cells to nascent HDL?

Back 184

LCAT

Front 185

What enzyme does HDL use to deposit cholesterol onto LDL (which then goes back to liver)?

Back 185

CETP (cholesterol ester transfer protein)

Front 186

How does HDL deposit cholesterol directly onto liver?

Back 186

SRB1

Front 187

What happens to cholesterol in liver?

Back 187

turned into bile acids, which can be excreted or reabsorbed

Front 188

Where does fatty acid synthesis occur?

Back 188

cytosol

Front 189

What is the rate limiting enzyme in fatty acid synthesis?

Back 189

acetyl coA carboxylase

Front 190

What is the rate-limiting enzyme of fatty acid breakdown?

Back 190

carnitine acyltransferase 1

Front 191

sx of carnintine deficiency?

Back 191

weakness, hypotonia, hypoketotic hypoglycemia

Front 192

Where does fatty acid degradation occur?

Back 192

mitochondria

Front 193

What enzyme esterifies 2/3 of body cholesterol?

Back 193

LCAT (lecithin-cholesterol acyl transferase)

Front 194

What is the first enzyme in the urea cycle? Where is it located?

Back 194

carbamoyl phosphate synthetase 1, in mitochondria

Front 195

What enzyme catalyzes carbamoyl phosphate --> citrulline + ornithine

Back 195

ornithine transcarbamoylase

Front 196

Name three findings in OTC deficiency

Back 196

decreased BUN (no urea in blood), hyperammonemia, increased orotic acid in blood and urine

Front 197

What must a transcription factor do?

Back 197

bind to promotor region

Front 198

What are other names for the promotor region?

Back 198

-25 Hogness/pribnow/TATA box/-75 CAAT

Front 199

Name 4 structural motifs TFs can have to bind DNA

Back 199

helix loop helix, helix turn helix, zinc finger, leucine zipper

Front 200

What is the difference between a repressor/inducer in the operator region and an enhancer or repressor region?

Back 200

the former controls whether or not transcription occurs, the latter controls the rate of transcription when bound by protein factors

Front 201

What chemical inhibits eukaryotic RNA pol II?

Back 201

alpha amanitin, found in death cap mushrooms

Front 202

What antibiotic inhibits prokaryotic RNA polymerase?

Back 202

rifampin

Front 203

Where is rRNA synthesized?

Back 203

nucleolus

Front 204

Where is tRNA/mRNA synthesized?

Back 204

nucleoplasm

Front 205

Name two ways of prokaryotic transcription termination

Back 205

- GC rich region followed by uracil rich region
- Rho factor of e. coli- ATPase just clips off polymerase

Front 206

Maple Syrup Urine Disease
1) What is the malfunction (inc. enzyme)
2) Which aas are affected?
3) What are the physical findings?

Back 206

1) can't break down branched chain aas (lack of alpha keto acid dehydrogenase)
2) leucine, isoleucine, valine
3) Urine smells like maple syrup, CNS defects, MR, death

Front 207

Hartnup's Disease
1) Genetics?
2) What's defective?
3) Where is it?
4) Findings?

Back 207

1) autosomal recessive
2) neutral aa transporter
3) renal and intestinal epithelial cells
4) pellagra (bc tryptophan needed to make niacin), tryptophan excretion from urine

Front 208

For each disease, name the deficient enzyme, accumulated substance, genetics, and main findings:
Fabry's

Back 208

1) Enzyme: alpha galactosidase
2) Substrate: ceramide trihexoside
3) Genetics: x-linked recessive
4) Findings: peripheral neuropathy of hands/feet, angiokeratomas, cardio/renal disease

Front 209

For each disease, name the deficient enzyme, accumulated substance, genetics, and main findings:
Gaucher's

Back 209

1) Enzyme: beta-glucocerebrosidase
2) Substrate: glucocerebroside
3) Genetics: autosomal recessive
4) Findings: hepatosplenomegaly, aseptic necrosis of femur, bone crises, crumpled tissue paper macrophages

Front 210

For each disease, name the deficient enzyme, accumulated substance, genetics, and main findings:
Niemann Pick Disease

Back 210

1) Enzyme: sphingomyelinase
2) Substrate: sphingomyelin
3) Genetics: autosomal recessive
4) progressive neurodegeneration, hepatosplenomegaly, cherry red macula, foam cells, severe MR

Front 211

For each disease, name the deficient enzyme, accumulated substance, genetics, and main findings:
Tay-Sachs Disease

Back 211

1) Enzyme: hexosaminidase A
2) Substrate: GM2 ganglioside
3) Genetics: autosomal recessive
4) Findings: progressive neurodegeneration, seizures, developmental delay, cherry red macula, lysosomes w/ onion skinning

Front 212

For each disease, name the deficient enzyme, accumulated substance, genetics, and main findings:
Krabbe's Disease

Back 212

1) Enzyme: Galactocerebrosidase
2) Substrate: galactocerebroside
3) Genetics: autosomal recessive
4) Findings: peripheral neuropathy, developmental delay, optic atrophy, globoid cells

Front 213

For each disease, name the deficient enzyme, accumulated substance, genetics, and main findings:
Metachromatic Leukodystrophy

Back 213

1) Enzyme: Arylsulfatase A
2) Substrate: Cerebroside Sulfate
3) Genetics: autosomal recessive
4) Findings: central and peripheral demyelination with ataxia, dementia

Front 214

For each disease, name the deficient enzyme, accumulated substance, genetics, and main findings:
Hurler's

Back 214

1) Enzyme: alpha-L-iduronidase
2) Substrate: heparan sulfate, dermatan sulfate
3) Genetics: autosomal recessive
4) Findings: developmental delay, gargoylism, airway obstruction, corneal clouding

Front 215

For each disease, name the deficient enzyme, accumulated substance, genetics, and main findings:
Hunter's

Back 215

1) Enzyme: iduronadate sulfatase
2) substrate- dermatam sulfate, heparan sulfate
3) Genetics: x-linked recessive
4) Mild Hurler's + aggressive behavior, NO corneal clouding

Front 216

I Cell Disease
1) Description
2) Molecular consequences
3) Findings

Back 216

1) Failure of addition of mannose 6 phosphate to lysosome proteins
2) enzymes secreted outside the cell instead of targeted to lysosomes
3) Findings: coarse facial feature, restricted joint movement, high plasma levels of lysosomal enzymes +/- MR

Front 217

Which lysosomal storage disease is associated with renal failure?

Back 217

Fabry's disease

Front 218

Which two lysosomal storage diseases are x-linked recessive?

Back 218

Fabry's and Hunter's

Front 219

Most common lysosomal storage disease?

Back 219

Gaucher's

Front 220

Which lysosomal storage diseases are associated with early death?

Back 220

Tay Sachs, Niemann Pick, Krabbe's

Front 221

Which lysosomal storage disease is a demyelinating disease?

Back 221

Metachromatic Leukodystrophy

Front 222

Which disease are these deficiencies associated with?
1) alpha-L-iduronidase
2) Iduronadate sulfatase
3) Failure of addition of mannose 6 phosphate to lysosome proteins

Back 222

1) Hurler's disease
2) Hunter's
3) I-cell disease

Front 223

Name the disease assoc. with these enzyme deficiencies:
1) alpha galactosidase A
2) beta glucocerebrosidase
3) sphingomyelinase
4) hexosaminidase A

Back 223

1) Fabry's
2) Gaucher's
3) Niemann Pick
4) Tay Sachs

Front 224

Name the disease assoc. with these enzyme deficiencies:
1) galactocerebrosidase
2) arylsulfatase A

Back 224

1) Krabbe's disease
2) metachromatic leukodystrophy

Front 225

3 complications of marfan syndrome

Back 225

1) aortic incompetence --> dissecting aortic aneurysms
2) floppy mitral valve
3) subluxation of lenses
also berry aneurysms

Front 226

Genetics of marfan syndrome

Back 226

autosomal dominant

Front 227

Albinism could be a deficiency of what two things?

Back 227

tyrosinase (enzyme that catalyzes tyrosine --> melanin) or defective tyrosine transporters

Front 228

What is a non-enzymatic cause of albinism?

Back 228

failure of neural crest cells to migrate

Front 229

What type of inheritence is tyrosinase deficiency?

Back 229

autosomal recessive

Front 230

Describe how transaminases are made

Back 230

based on donor of amino group (ie alanine aminotransferase)

Front 231

What cofactor is required for aminotransferases? what is it derived from?

Back 231

cofactor- pyridoxal phosphate
derived from- vitamin B6

Front 232

What are the cofactors needed by the pyruvate dehydrogenase complex?

Back 232

thiamine (B1), lipoic acid, coA (B5), FAD (B2), NAD (B3)

"Tender Loving Care for No One"

Front 233

What rxn does pydruvate dehydrogenase complex catalyze?

Back 233

pyruvate --> acetyl coA

Front 234

Where does glucose 6P --> glucose?

Back 234

in the ER

Front 235

What does the CFTR transporter do?

Back 235

actively secretes Cl- in lungs and GI tract and actively reabsorbs Cl- from sweat

Front 236

What is the most common mutation in CF?

Back 236

Deletion of Phe 508

Front 237

CF complications?

Back 237

recurrent pulmonary infections, bronchiti, bronchiectasis, pancreatic insufficiency, meconium ileus

Front 238

Why are males who have CF infertile?

Back 238

bilateral absence of vas deferens

Front 239

Name two bacteria that cause infection in CF

Back 239

pseudomonas & S. aureus

Front 240

Name another disease associated with meconium ileus

Back 240

Hirschsrpung's disease

Front 241

signs/sx of prader willi

Back 241

hypotonia, poor feeding, almond shaped eyes, down-turned mouth. later: hyperphagia, obesity, short stature, MR, behavior disorders (skin picking), hypogonadotropic hypogonadism

Front 242

Signs/sx of Angelman syndrome

Back 242

"happy puppet" syndrome, ataxia, inappropriate laughter

Front 243

Name sample & probe for southern, northern, western blots:

Back 243

Southern- sample DNA, probe DNA
Northern- sample RNA, probe DNA
Western- sample protein, probe Ab

Front 244

Describe how FISH works

Back 244

fluorescent DNA or RNA probe binds to gene of interest --> fluorescence indicates gene of interest is present

Front 245

What phase of mitosis are chromosomes in for karyotype?

Back 245

metaphase

Front 246

What type of antiobiotic binds 30s subunit, preventing tRNA attachment?

Back 246

tetracycline

Front 247

What type of antiobiotic inhibits formation of the inititation complex and causes misreading of mRNA?

Back 247

aminoglycosides

Front 248

Which site does first Met get put in in ribosome?

Back 248

P site

Front 249

Where do other incoming tRNAs get put?

Back 249

A site

Front 250

What does ribozyme (aka peptidyl transferase) do?

Back 250

transfers growing polypeptide (P site) to new aa (A site)

Front 251

Findings in Down Syndrome?

Back 251

MR, flat facies, prominent epicanthal folds, simian crease, gap bt 1st and 2nd toes, duodenal atresia, congenital heart disease (endocardial cushion defects)

Front 252

What 3 things are DS patients at risk for later in life? (other than heart problems)

Back 252

ALL, AML, Alzheimer's disease

Front 253

What would you see on quad screen with Down Syndrome?

Back 253

decreased AFP, increased beta hCG, decreased estriol, increased inhibin A

Front 254

What would DS ultrasound show?

Back 254

nuchal translucency (could also see with Turner's)

Front 255

What would you use for definitive DS diagnosis?

Back 255

FISH

Front 256

95% of cases of DS are due to?

Back 256

meiotic nondisjunction

Front 257

Describe what's being made and being used:
post absorptive period (4-6 hours)

Back 257

made- glucose (via glycogenolysis and a little bit of gluconeogenesis), adipose is releasing FFAs
Mostly glucose is being used

Front 258

Describe what's being made and being used:
early starvation (24 hours)

Back 258

Made- glucose via glycogenolysis (less) and gluconeogenesis (more), FFAs
Brain/RBCs use glucose, muscle & liver use FFAs

Front 259

Describe what's being made & being used: intermediate starvation (2-3 days)

Back 259

glucose made via gluconeogenesis, FFAs, ketone bodies
Brain uses glucose and ketone bodies, muscle/liver use FFAs, ketone bodies (can't be used by liver)

Front 260

Which organ can't use ketone bodies?

Back 260

liver

Front 261

Name 3 diseases where you would see high ketone bodies?

Back 261

1) diabetic ketoacidosis
2) alcoholism
3) prolonged starvation

Front 262

What is the rate limiting enzyme for ketogenesis?

Back 262

Hmg CoA synthase

Front 263

Name the essential aas

Back 263

Phe, Val, Trp, Thr, Ile, Met, His, Arg, Leu, Lys

Front 264

Name three basic aas

Back 264

Arg, Lys, His

Front 265

When do you need to supplement ketogenic aas?

Back 265

in pyruvate dehydrogenase deficiency

Front 266

Draw the pathway of phenylalanine to Epi

Back 266

See FA p. 106

Front 267

What's the treatment for classic galactosemia?

Back 267

avoid galactose and lactose

Front 268

Huntington's disease:
1) Chromosome
2) Trinucleotide repeat?
3) Findings?
4) Neurotransmitters that are unusual

Back 268

1) 4
2) CAG
3) Depression, dementia, choreiform movements, caudate atrophy
4) Decreased GABA, decreased AcH

Front 269

Myotonic dystrophy, trinucleotide repeat?

Back 269

CTG

Front 270

What is the inheritence of phenylketonuria?

Back 270

autosomal recessive

Front 271

What is the inheritence of hemochromatosis?

Back 271

autosomal recessive

Front 272

What is the inheritence of thalassemias?

Back 272

autosomal recessive

Front 273

What is the inheritence of sickle cell anemias?

Back 273

autosomal recessive

Front 274

Findings in fragile x?

Back 274

macro-orchidism (enlarged testes), long face with large jaw, large everted ears, autism, mitral valve prolapse

Front 275

Trinucleotide repeat in fragile x?

Back 275

CGG

Front 276

Electron Transport:
What happens at complex I?

Back 276

NADH --> NAD+

Front 277

Electron Transport:
What happens at complex II?

Back 277

FADH --> FAD+

Front 278

Protons are being transferred from where to where in electron transport chain?

Back 278

mitochondrial matrix --> intermembranous space, across inner mitochondrial membrane

Front 279

Drugs that inhibit complex I?

Back 279

amobarbital, rotenone, amytal, MPP (from meperidine, street drug)

Front 280

Drugs that inhibit complex III?

Back 280

Antimycin A

Front 281

Drugs that inhibit complex IV?

Back 281

H2S, CO, CN-, N3

Front 282

Name three uncoupling agents

Back 282

2,4 DNP (wood preservation agent), aspirin, thermogenin in brown fat

Front 283

What's the difference between kinase and phosphorylase?

Back 283

kinase- uses ATP to add PO4

phosphorylase- no ATP to add PO4

Front 284

What does phosphatase do?

Back 284

removes phosphate

Front 285

What does dehydrogenase do?

Back 285

oxidizes substrate

Front 286

What does carboxylase do?

Back 286

adds one carbon

Front 287

What is the normal cofactor for carboxylase?

Back 287

biotin

Front 288

Name the chemical moiety carried by the carrier:
ATP

Back 288

phosphoryl groups

Front 289

Name the chemical moiety carried by the carrier:
NADH/FADH2

Back 289

electrons

Front 290

Name the chemical moiety carried by the carrier:
coenzyme A/lipoamide

Back 290

acyl groups

Front 291

Name the chemical moiety carried by the carrier:
biotin

Back 291

CO2

Front 292

Name the chemical moiety carried by the carrier:
TH4

Back 292

1-carbon units

Front 293

Name the chemical moiety carried by the carrier:
SAM

Back 293

methyl groups

Front 294

Name the chemical moiety carried by the carrier:
TPP

Back 294

aldehyde

Front 295

Describe how methionine --> homocysteine (and back)

Back 295

see FA insert page that I added (near p. 68

Front 296

Name enzyme and sx:
Galactokinase deficiency

Back 296

enzyme- galactokinase

sx- milder, galactose in blood/urine, infantile cataracts, developmental delay

Front 297

Name the enzyme and sx:
Classic galactosemia

Back 297

enzyme: galactose-1-phoasphate uridyl transferase

Findings: galactitol accumulates in lens of eye --> cataracts, failure to thrive, MR, jaundice, hepatomegaly

Front 298

How is classic galactosemia different from Hurler's/Hunter's disease (regarding eyes)?

Back 298

galactosemia- cataracts, Hurler's- corneal clouding & gargoylism, Hunter's- no eye pathology

Front 299

Name the enzyme:
Tyr --> DOPA

Back 299

Tyrosine hydroxylase

Front 300

DOPA --> dopamine

Back 300

dopa decarboxylase

Front 301

What drug inhibits DOPA decarboxylase?

Back 301

carbidopa

Front 302

What enzymes break down dopamine and NE?

Back 302

MAO and COMT

Front 303

What is the dopamine breakdown product?

Back 303

homovanillic acid (HMA)

Front 304

What is the NE breakdown product?

Back 304

vanillymanelic acid (VMA)

Front 305

What two things can go wrong that --> PKU

Back 305

missing phenylalanine hydroxylase
missing BH4 cofactor

Front 306

What aa "becomes" essential in PKU?

Back 306

tyrosine

Front 307

Name three phenylketones & what are they?

Back 307

They are the product of having excess Phe-

Phenylacetate, phenyllactate, and phenylpyruvate

Front 308

Findings in PKU?

Back 308

musty body odor, increased phenylketones, fair skin (no melanin), eczema, MR, seizures, growth retardation

Front 309

Findings in babies with untreated PKU moms?

Back 309

microcephaly, MR, growth retardation, heart defects

Front 310

Alkaptonuria:
What is deficienct?

Back 310

homogentisic acid oxidase

Front 311

Alkaptonuria:
What does the deficient enzyme normally do?

Back 311

tyrosine --> fumarate

Front 312

Findings in alkaptonuria?

Back 312

dark connective tissue, pigmented sclera, urine turns black on standing, can get arthralgias

Front 313

Name three post-translational modifications of mRNA before it leaves the nucleus

Back 313

5' cap, poly A tail, splicing out of introns

Front 314

Where on the tRNA molecules does the aminoacyl tRNA synthetase add an AA?

Back 314

the 3' hydroxyl

Front 315

Which antibiotics bind the 30S subunit, preventing aminoacyl tRNA attachment?

Back 315

tetracyclines

Front 316

CF treatment?

Back 316

N-acetylcysteine (cleaves disulfide bonds and loosens mucus plugs), antibiotics, pancreatic enzymes, fat soluble vitamins

Front 317

MEN 1 - common malignancies

Back 317

parathyroid (PTH), pancreatic, pituitary

Front 318

MEN 2A- common malignancies

Back 318

medullary thyroid, pheochromocytoma, parathyroid

Front 319

MEN 2B- common malignancies

Back 319

medullary thyroid, pheochromocytoma, oral/intestinal ganglioneuromatosis (assoc. with marfanoid habitus)

Front 320

Two of the MEN syndromes are associated with a mutation; which ones, and what mutation?

Back 320

MEN2A/2B, ret mutation

Front 321

Inheritence of MEN syndromes?

Back 321

autosomal dominant

Front 322

Friedrich's ataxia- associated trinucleotide repeat?

Back 322

GAA

Front 323

Fragile X syndrome:
1) Genetics
2) Gene involved?
3) What does # 2 do?
4) Name the two most common causes of genetic MR.

Back 323

1) x-linked recessive
2) FMR1 (fragile mental retardation)
3) codes for FMR protein--> found in brain and testes, involved in axon/dendrite mRNA translation
4) Down Syndrome & fragile x

Front 324

Tryptophan --> (2 things)

Back 324

1) Niacin, 2) Serotonin

Front 325

histadine -->
Cofactor?

Back 325

histamine , B6

Front 326

Glycine --> ? --> ?

Back 326

porphyrin, heme

Front 327

Arginine --> (3)

Back 327

1) creatine
2) urea
3) Nitric oxide

Front 328

glutamate --> (2)

Back 328

1) GABA
2) Glutathione

Front 329

Cofactor for glutamate --> GABA?

Back 329

B6

Front 330

Name the enzyme:
Phe --> Tyr

Back 330

Phe hydroxylase