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Behavioral science, biostats, biochem, genetics Flashcards

1
Q

MoA of MTX, TMP, and pyramethamine?

A

Inhibit dihydrofolate reductase (can’t convert DHT back to THF)

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2
Q

Drug w/MoA similar to mycophenolate?

A

Ribavirin

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3
Q

Cause of Lesch-Nyhan syndrome?

A

Defective purine salvage due to absent HGPRT (converts hypoxanthine to IMP and guanine to GMP).

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4
Q 
Sx of Lesch-Nyhan?
H
G
P
R
T
A 
H = hyperuricemia
G = gout
P = pissed off (aggression, self-mutilation)
R = retardation
T = dysTonia
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5
Q

Lesch-Nyhan: inheritance?

A

X-linked recessive

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6
Q

Name an antibiotic category that’s a topoisomerase II & IV inhibitor in prokaryotes.

Name an anti-neoplastic agent that is the same for eukaryotic cells.

A

Fluoroquinolones

Etoposide/tenoposide (“topo”)

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7
Q

What disease has defective nucleotide excision repair?

A

Xeroderma pigmentosa (prevents repair of pyrimidine dimers due to UV light exposure)

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8
Q

When does NER occur?

A

G1

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9
Q

When does base excision repair occur?

A

Throughout cell cycle

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10
Q

What disease has defective mismatch repair?

A

Lynch syndrome (HNPCC)

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11
Q

When does MMR occur?

A

G2

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12
Q

Fanconi anemia and ataxia-telangiectasia are both eg’s of diseases where what is mutated?

A

Nonhomologous end-joining

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13
Q

What anti-biotic inhibits RNA poly in prokaryotes?

What anti-neoplastic can do it in eukaryotes (+ prokaryotes)?

A

Rifampin

Actinomycin D

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14
Q

What are anti-Smith AB’s targeting?

What dz are they specific for?

A

snRNP’s (small nuclear ribonucleoproteins)

SLE

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15
Q

What do snRNP’s do?

A

Combine w/primary transcript (forms spliceosome), looping occurs, and intron is excised (exons are joined together)

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16
Q

What sequence is found at the acceptor stem of tRNAs?

A

CAA

“can carry aa’s”

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17
Q

Explain the cascade of events starting at p53 and ending in inhibition of the cell cycle.

A
  1. p53 induces p21, which inhibits CDKs, leading to hypo-P’lation of Rb
  2. Hypo-P’lated Rb binds to and inactivates E2F (ts factor), leading to inhibition of G1-S phase
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18
Q

Name some ‘permanent’ cell types that only regenerate from stem cells.

Name some “stable” (quiescent) cells that can enter G0 from G1 when stimulated.

A
  • Neurons, skeletal + cardiac muscle, RBCs

- Hepatocytes, lymphocytes

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19
Q

What is the name of rER in neurons?

A

Nissl bodies (synthesize peptide NT’s for secretion)

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20
Q

What types of cells are rich in sER?

What types of cells are rich in rER?

A

Any cells that produce steroid hormones or participate in drug/poison detox (eg adrenal cells or hepatocytes)

Cells that export/secrete lots of stuff (eg goblet cells or plasma cells)

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21
Q

What’s the cellular marker for trafficking to the lysosome?

A

Mannose-6-phosphate

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22
Q

What is the name of the disease where the golgi can’t P’late mannose and proteins are sent out of the cell rather than being degraded by lysosome?

A

I-cell disease (inclusion cell disease/mucolipidosis type II)

[typical features- course facial features, clouded corneas, restricted joint movement. Fatal usually in chidlhood.]

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23
Q

What ribonucleoprotein traffics proteins from ribosome to rER?

A

Signal recognition peptide (SRP)

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24
Q

What protein coats endosomes and transports from rER to golgi?

Golgi to rER (retrograde)?

What processes does clathrin participate in?

A

COPII

COPI

Clathrin:
Trans-golgi to lysosomes.
PM to endosomes (eg LDLR reuptake)

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25
Defects in the proteosome have been implicated in some forms of what disease?
Parkinson disease
26
What does vimentin stain? (intermediate filament)
Mesenchymal tissue (eg fibroblasts, endothelial cells, macrophages)
27
What does desMin stain? (intermediate filament)
Muscle
28
What does cytokeratin stain? (intermediate filament)
Epithelial cells
29
What does Gfap stain? (intermediate filament)
NeuroGlia (eg astrocytes, schwann cells, oligodendroglia)
30
What does neurofilament stain? (intermediate filament)
Neurons
31
Name the drugs that act on microtubules? (what is mnemonic?)
"MT's Get Constructed Very Poorly" ``` Mebendazole (antihelminthic) Griseofulvin (antifungal) Colchicine (antigout) Vincristine/Vinblastine (antineoplastic) Paclitaxel (antineoplastic) ```
32
What cardiac drug inhibits the NKP?
``` Cardiac glycosides (digoxin & digitoxin) - Leads to indirect inhibition of Na/Ca exchange, leading to increased intracellular Ca and increased contractility! ```
33
(What plan-derived toxin binds to the NKP at the K+ site to inhibit it?)
(Ouabain)
34
Where are the 4 types of cartilage found? | recall mnemonic
"Be (so totally) Cool, Read Books" bONE, (skin, tendon): type I CarTWOlage: type II Reticulin, blood vessels: type III BM: type IV
35
Which collagen is defective in osteogenesis imperfecta type 1?
Type I
36
Which collagen is defective in the rare vascular form of Ehler-Danlos syndrome? (Classical Ehlers-Danlos?)
Type III | Type V
37
What type of collagen is defective in Alport syndrome and targeted by AB's in Goodpasture syndrome?
Type IV (BM)
38
What step in collagen synthesis is required for procollagen formation?
Glycosylation
39
Which part of collagen synthesis are Ehlers-Danlos and Menkes disease a/w?
Crosslinking (final step in ECF) of tropocollagen
40
Which part of collagen synthesis is osteogenesis imperfecta a/w?
Glycosylation
41
What genes are most commonly mutated in osteogenesis imperfecta?
COL1A1 and COL1A2
42
Menkes disease: inheritance pattern? Pathophys? Gene mutation? Sx?
- X-linked recessive - Imparied Cu absoprtion/xport - ATP7A (Menkes protein) -> decreased lysyl oxidase - Brittle, kinky hair; hypotonia, growth retardation
43
What enzyme can break down elastase?
Alpha1-antitrypsin
44
Name the glycoprotein that forms a sheeth around elastin.
Fibrillin (mutated in Marfan)
45
McCune-Albright syndrome: Cause? Sx? Lethal if?...
- Due to mutation in G-protein signalling - Sx: cafe-au-lait spots, polyostotic fibrous dysplasia, precocious puberty, multiple endocrine abnormalities - Lethal if mutation occurs before fertilization (affecting all cell), but survivable if mosaicism
46
What is heteroplasmy?
Presence of both nl and mutated mtDNA, resulting in variable expression of mitochondrially inherited disease.
47
Rett syndrome, fragile X syndrome, and alport syndrome are all eg's of what inheritance pattern?
X-linked dominant
48
What is MELAS syndrome? | Inheritance pattern?
M E mitochondrial encephalopathy L A lactic acidosis S stroke-like episodes Mitochondrial inheritance (ragged red fibers on muscle bx)
49
Gene mutated in achondroplasia?
FGFR3 (inhibits chondrocyte proliferation)
50
Gene mutated in FAP?
APC
51
Gene mutated in familial hypercholesterolemia?
LDLR
52
Generally, hereditary hemorrhagic telangiectasia is a d/o of ____________.
Blood vessels.
53
Gene mutated in Li-Fraumeni? Nickname?
(T)P53 SBLA: sarcoma, breast, leukemia, adrenal
54
What is a common deletion seen in CF? (AR)
Phe508
55
What test is diagnostic for CF?
Increased Cl- in the sweat
56
Name the X-linked recessive d/o's. "Oblivious Females Will Often Give Her Boys Her x-Linked Disorders"
"Oblivious Females Will Often Give Her Boys Her x-Linked Disorders" ``` OTC deficiency Fabry disease Wiskott-Aldrich syndrome Ocular albinism G6PD deficiency Hunter syndrome Bruton agammaglobulinemia Hemophilia A & B Lesch-Nyhan syndrome Duchenne (& Becker) muscular dystrophy ```
57
What type of mutation is Duchenne muscular dystrophy due to?
Frameshift (Beck is non-frameshift)
58
What's the mnemonic to remember the sx of myotonic dystrophy type 1? (AD)
``` My Tonia (myotonia) My Testicles (atrophy) My Toupee (frontal balding) My Ticker (arrhythmia) ```
59
What are the repeats in the NT expansion diseases?
Huntington: CAG Fragile X: CGG Friedrich ataxia: GAA Myotonic dystrophy: CTG
60
How could you distinguish Edwards from Patau?
Edwards: low set Ears Patau: cleft liP/Palate, holoProsencephaly, Polydactyly
61
What does Cri-du-chat mean? Other sx?
"Cry of the cat" Microcephaly, retardation, epicanthal folds, VSD
62
DiGeorge and velocardiofacial syndromes (22q11 microdeletion) are due to aberrant development of the _____________________.
3rd & 4th branchial pouches
63
What is the name of the following B vitamins? | B1, B2, B3, B5, B6, B7, B9, B12
``` B1 = thiamine B2 = Riboflavin B3 = Niacin B5 = pantothenic acid ("pento"thenic acid) B6 = Pyridoxine B7 = biotin B9 = folate B12 = cobalamin ```
64
What enzyme links glycoslysis to the TCA cycle?
Pyruvate DH
65
What reactions is thiamine (B1) important for? | think "ATP"
Alpha-ketoglutarate DH Transketolase Pyruvate DH Ber1 Ber1
66
What are the 2 C's of B2 deficiency?
- Cheilosis (inflammation of the lips, scaling and fissures at corner of mouth) - Corneal vascularization
67
What are the 3 D's of B3 def?
- Diarrhea - Dementia - Dermatitis (Casal's necklace)
68
How is folate (B9) obtained in the diet?
"Fol"iage (green, leafy vegis)
69
What is the main symptom caused by folate def? (B9)
Megaloblastic anemia (no neuro sx)
70
Which vitamin def. can cause subacute combined degeneration?
B12 (cobalamin) Also can cause megaloblastic anemia like B9.
71
Sx of Zn def?
* Delayed wound healing - Hypogonadism - Decreased adult hair - Dysgeusia/anosmia - Acrodermatitis enteropathica
72
What is marasmus?
Total calorie malnutrition | "Marasmus results in Muscle wasting"
73
Besides edema, why can you get a fatty liver in Kwashiorkor (protein malnutrition)?
Decreased apolipoprotein synthesis | you also get anemia
74
___________ causes glycolysis to produce zero net ATP (vs. 2).
Arsenic [Arsenic inhibits lipoic acid (TCA), causing vomiting, rice water stools, garlic breath.]
75
What is the function of the pyruvate DH complex? Name the 5 required cofactors.
Links glycolysis w/TCA cycle (pyruvate -> acetyl-CoA) B1-B5 + lipoic acid (there's no B4)
76
In pyruvate DH complex deficiency (X-linked), where are the 2 places that excess pyruvate gets shunted?
- To lactate (via LDH) | - To Alanine (via ALT)
77
What are the onLy pureLy ketogenic AA's? (used to treat pyruvate DH complex def.)
Lysine | Leucine
78
In what cell types is pyruvate conversion to lactate (cori cycle) used predominantly instead of TCA cycle? (via LDH)
Anaerobic glycolysis: - RBCs - WBCs - Kidney medulla - Lens - Cornea - Testes
79
What inhibits complex I of ETC?
Rotenone (rotenONE)
80
What inhibits complex III of ETC?
Antimycin A (an-3-mycin A)
81
What inhibits complex IV of ETC?
CO/CN (4 letters) - This step converts 1/2 O2 + 2H+ to water, so makes sense that these could bind
82
What inhibits the ATP synthase of the ETC?
Oligomycin
83
List 3 agents that can uncouple the ETC.
* 2,4-dinitrophenol (weight loss) * Aspirin (fever s/p ASA OD) * Thermogenin in brown fat (produces heat)
84
What is the reason we have the pentose phosphate pw? (HMP shunt?)
Provides source of NADPH (eg for glutathione reduction in RBCs, FA/chol biosynthesis for steroids...). Also yields ribose for NT synthesis and glycolytic intermediates. Sites: lactating mammary glands, liver, adrenal cortex, RBCs
85
What is the rate-limiting enzyme of the PPP (HMP shunt)? Deficiency causes what disease?
*Glucose-6-phosphate DH (most common enzyme def. in humans!) This is why you get Heinz bodies in G6PD def.--denatured Hgb ppt's w/in RBCs due to oxidative stress since PPP is defunct, can't reduce glutathione to protect RBCs.
86
What enzyme is absent in galactosemia, leading to the toxic buildup of galactitol?
Galactose-1-phosphate uridyltransferase
87
In what inborn error of metabolism would you smell a musty body odor?
PKU (Pee-(K)-yew) + Retardation + Fair skin Phe hydroxylase def.
88
What 3 AA's build up in maple syrup urine disease?
"I Love Vermont" maple syrup Isoleucine Leucine Valine (branched)
89
While the lens is subluxated upwards in Marfan, in what disease would it be downwards?
Homocystinuria (cystathione synthase def.) + Homocysteine in urine + Retardation + Osteoporosis + *Marfanoid habitus + Kyphosis + Thrombosis, atherosclerosis (stroke, MI)
90
What do cystine stones appear like? What other protein's are also lost in the urine? (COLA)
Hexagonal COLA: cystine, ornithine, lysine, arginine
91
Tx for cystine stones? What test is diagnostic?
- Urinary alkalinization + chelation (eg penicillamine), hydration - Urinary cyanide-nitroprusside test
92
What are the 2 major pw's inhibited in Von Gierke disease?
GNG & glycogenolysis | def. glucose-6-phosphatase
93
Where does FA synthesis generally occur? (3)
Liver Lactating mammary glands Adipose tissue
94
What shuttle brings citrate into the mito for FA synthesis? What shuttle brings fatty acyl-CoA out of the mito for energy use?
Citrate shuttle Carnitine shuttle
95
Where is lipoprotein lipase (LPL) found, and what does it do?
Vascular endothelial surface Degrades TG's circulating in chylomicrons & VLDLs
96
Hormone-sensitive lipase degrades TGs stored in _______________.
Adipocytes
97
What does LCAT do?
Catalyzes esterification of cholesterol
98
What does apolipoprotein A-I do?
Activates LCAT | chylomicrons, HDLs
99
What does apolipoprotein C-II do?
LPL cofactor | chylomicrons, HDLs, VLDLs
100
What does apolipoprotein E do?
Mediates remnant uptake | All except LDLs
101
What does apolipoprotein B-48 do?
Mediates chylomicron secretion | chylomicrons, remnants
102
What does apolipoprotein B-100 do?
Binds LDLR | VLDLs, IDLs, LDLs
103
What are the familial dyslipidemias type I, IIa, and IV?
I = hyper-chylomicronemia (AR; LPL or apo-CII def.) II = familial hypercholesterolemia (AD; LDLR problem) IV = hyper-triglyceridemia (AD; overproduction of VLDLs)

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