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Y biochem final > open questions > Flashcards

open questions Flashcards

1
Q

substrates + cofactors for methyl malonyl Coa mutase

A

L-methylmalonyl –> succinyl Coa

cofactor: B12

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2
Q

what organs will be affected by glycogen storage disease

A

skeletal m + liver

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3
Q

position of the OH group in primary bile acids + config

A

(3,7,12) alpha- outward position

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4
Q

threonine dehydratase. cofactor and sub + prod

A

threonine –> a-ketobutyrate
cofactor: PLP
get free NH3 !!!

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5
Q

precursors of LDL, what enzyme?

A

IDL, hepatic lipase

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6
Q

enzymes in FA synt that reduces NADPH

A

b-ketoacyl ACP reductase

enoyl-ACP reductase

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7
Q

enzymes that covalent modi PDH

A

pyruvate DH kinase - inhibits PDH

pyruvate DH phosphatase - activates PDH

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8
Q

what does PP1 do?

A 
activate glycogen synthase (by dephosphos)
inhibit GP (by depos), GPK
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9
Q

what does phosphoglucose mutase

A

G-6-P –> G-1-P

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10
Q

UMP synthase - reaction

A

UMP synthase consist of both orotate phosphoribosyl transferase and OMP decarboxylase.
Orotate –> omp –> UMP
need PRPP and get CO2

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11
Q

hydroxybutyrate DH reaction + cofactor

A

b-hydroxybutyrate –> acetoacetate

need NAD+

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12
Q

what is the low affinity glucose transporter?

A

GLUT-2

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13
Q

what does glycogen phosphorylase

A

glygocen –> G-1-P

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14
Q

what kind of nucleotide binding site does muscle glycogen phosphorylase have?

A

AMP

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15
Q

common cofactors required for both a-KG DH and pyruvate DH

A 
TPP (E1)
Lipoid acid (E2)
CoA-SH (E3)
NAD (E3)
FAD (E3)
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16
Q

which reaction is catalyzed by UDP-glucose pyrophosphorylase?

A

G-1-P –> UDP-glucose

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17
Q

enzymes req for transport of long chain FA into mitochon

A

Acyl Coa synthase
CAT1
CAT2
(Translocase)

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18
Q

how many FADH2 is prod per palmitate (16C)?

A

7 FADH2

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19
Q

2 diff cell receptors in cholesterol uptake in hepatocytes

A

SR-B1

LDL receptors

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20
Q

major intracellular target of statins?

A

HMG Coa reducctase

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21
Q

ALAT

A

Alanine –> pyruvate

w/help of a-KG –> glu

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22
Q

Glutamate DH

A

Glutamate –> a-KG

w/ NADPH+ H2O –> NADP + NH3

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23
Q

enzyme blocked in fructosesuria

A

Frucotse kinase

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24
Q

enzyme blocked in fructose intoleranse

A

Aldolase B

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25
Q

Pyruvate carboxylase, substrate, prod + cofactors

A

Pyruvate –> Oxaloactetate

cofactor: biotin, Mg2+

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26
Q

Acetyl CoA carboxylase - function + cofactor

A

Acetyl Coa –> malonyl CoA

Cof: Biotin

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27
Q

name an ionophore that uncouples proton pumping for ATP synthesis in mitochondria.

A

DNP-2,4-dinitrophenol

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28
Q

Cholesterol uptake by liver

A

LDL+IDL transport cholesterol to LDL-receptors

HDL takes up excess cholesterol and brings it into the liver via SC-B1

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29
Q

Adenylyl cyclase reaction

A

ATP–> cAMP + Pi

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30
Q

Which cell have GLUT 2?

A

Pancreatic B-cells

Liver

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31
Q

Potassium ion is located in ____ of potassium ion chanel

A

Selectivity filter leading to the central cavity

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32
Q

Enzyme for glucoronidation?

A

UDP-glucuronosyltransferase (UGT)

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33
Q

What type of HDL component is resp for atherosclerosis?

A

Defective Apo-A1

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34
Q

CFTR is phosphorylated by what?

A

PKA

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35
Q

how do you inhibit NE

A

MAO, COMT

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36
Q

Biotransformation phase II reactions

A

Glucoronidation, sulfatation and glutathione

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37
Q

What can be detected in urine during metabolism of dopamine?

A

Homovanilic acid (HVA)

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38
Q

What can be detected in urine during metabolism of serotonin?

A

5-hydroxy indolence acid/monoamide oxidase

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39
Q

What can be detected in urine during metabolism of NE

A

MHPG and VMA

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40
Q

Primary target for Quabain/strophantine?

A

inhibition of Na+/K+ ATPase

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41
Q

how do we inhibit Na+/K+ ATPase?

A

Quabain/strophantine

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42
Q

the open probability of ion channels range from?

A

0-1

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43
Q

treatment of diabetes mellitus, how?

A

By sulphonylureas - these binds to the SUR unit and depolarize the insulin from the beta cells.

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44
Q

under normal condition ATP-sensitive K+ channels are activated by and inhibit by?

A

Activated by: ADP, Diazoxide

inhibited by: ATP, sulfonylureas

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45
Q

how is fibrinolysis terminated?

A

PAI 1/2, a2 antiplasmin a2 macroglobulin

clearance of fibrinolytic factors through liver

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46
Q

substrates for thrombin

A

anticogagulant:
- T+heprain –> ATIII
- T+TM –> protein C

Procoagulant:

  • T+TM –> TAFI
  • T+fibrin –> XIII
  • T+PLT –> V,VIII,XI, PAR
  • Fibrinogen –> fibrin
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47
Q

what is the dominant reaction in the first phase of biotransformation?

A

Oxidation - performed by cyp p450

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48
Q

what kind of metabolizer phenotypes are known due to SNP-s of drug metabolizing enzymes?

A

Poor metabolizer/extensive metabolizer

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49
Q

which enzymes catalyzes glucoronidation?

A

UDP-glucoronosyltransferase

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50
Q

wha kind of DNA binding domain is characteristic for steroid-thyroid-retinoid receptors?

A

Zinc-finger binding domain

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51
Q

which phase of biotransformation is mediated by transporters?

A

Phase 3 - multidrug resistant transporters

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52
Q

which are the most important xenobiotic inducer of CYP1 isoenzyme?

A

PAHs

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53
Q

What inhibits blood coagulation at sites of vessel wall injury?

A

Protein C - it binds w/thombin and TM.

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54
Q

List 3 triggers of platelets

A

ADP, thombin, PAF, Thromboxane A2

55
Q

Malic enzyme - sub+prod+cofac

A

malate –> pyruvate

makes NADPH!!!!!

56
Q

absence of which enzyme causes accumulation of methyl malonyl CoA?

A

methyl malonyl coa mutase

57
Q

What enzyme is deff in orotic aciduria?

A

UMP-synthase

which consist of dihydroorotate DH and rotate phosphoribosyl transferase

58
Q

role of GLUT-2 and glucokinase

A

both of them have high KM and low aff to glucose.

both regulate insulin secretion.

59
Q

name a transcription factor/protein that initiates transcript:

A

TATA box binding protein

60
Q

name a transcription inhibitor

A

rifampicin (only prokaryotes), actinomycin D(both), a-amatin (eukary)

61
Q

activity of telomerase

A

reverse transcriptase - add to the free 3’end

62
Q

which protein binds to the 5’cap during eukaryotic translation initiation?

A

eIF4

63
Q

from which vitamin does CoA derive from?

A

B5

64
Q

which metal ion can be found in the structure of vitamin B12?

A

Cobalt

65
Q

what is the fundamental difference between senescent and quiescent cells?

A 
sensescent = have stopped dividing!
quiscent = cell cycle is postponed. cell is in non-dividing phase.
66
Q

name at least 3 potential coenzymes for DH enzymes.

A

CoA, NAD+, FAD+

67
Q

what binds the central position of hemoglobin?

A

Heme

68
Q

what are the proteins of mismatch repair?

A

MutS, MutH, MutL

69
Q

what enzyme adds the cap to mRNA?

A

Cap methyltransferase

70
Q

what sorts of bonds get disrupted in case of DNA denaturation?

A

H-bonds and non covalent bonds between base pairs.

It destroys the secondary and tertiary structure.

71
Q

how many 2,3 BPG molecules are bound to a single myoglobin molecule?

A

none. its not bound to myoglobin but to hemoglobin.

72
Q

how dooncogens of DNA tumor viruses promote tumor formation?

A

they inhibit tumor suppressor proteins (ex.p53)

73
Q

what is the characteristic structure of silk fibrin?

A

beta pleated sheets.

74
Q

what is the secondary structure of collagen?

A

collagen helix

75
Q

role of zinc fingers

A

transciption factors

76
Q

direct targets of p53

A

p21, BAX, cyclin B

77
Q

2 inhibitors of G/S checkpoint of cell cycle

A

p53, p21, Rb

78
Q

2 inhibitors of G2/M checkpoint of cell cycle

A

ATM, Chk1, p53

79
Q

3 proteins involved in DNA repair

A

endonucleases, DNA polymerase, DNA ligase

80
Q

what is wobble principle?

A

that one AA might be coded by more than one codon!!

the third position

81
Q

role of the mRNA cap

A

help mRNA bind to ribosome + stability

82
Q

what checkpoint in the cell cycle are not controlled by embryonic stem cells?

A

G1/S

83
Q

types of DNA repair systems

A

mismatch repair, base excision repair, nucleotide excision, recombinant DNA repair.

84
Q

what is produced in the zona glomerulosa?

A

produce and secrete mineralocorticoid aldosterone

85
Q

hyperuricemia - which enzyme?

A

HPRT - lesch-Nyhan syndrome.

86
Q

cogenital adrenal hyperplasia?

A

defect in cyt P450

87
Q

3 ways to decrease blood cholesterol levels:

A

inhibition of HMG-Coa reductase by statins.
activation of LCAT
increase LDL receptors.

88
Q

Metabolic effects of LXR

A

LXR will sense oxysterol (which is a oxidized form of cholesterol). (so if we have a lot of oxysterol we will also have a lot of cholesterol, this mechanism is to decrease the cholesterol in the cel)This will regulate transcription factors:
CYP7A1 - increased bile acid synthesis
ABCA1 - increased cholesterol efflux
IDOL - decreased LDL receptors.

89
Q

what happens to glycolysis during hypoxia?

A

it increases (this is determined by PFK1. )

90
Q

what enzyme produces GTP in TCA cycle?

A

succinyl CoA synthase.

91
Q

give at least two functions of peroxisomes

A

B-oxidation of very long-chain fatty acids.

oxidation of alcohol to acetaldehyde

92
Q

what are the functions of SR-B1?

A

the scavenger receptors are involved in uptake of cholesterol esters from HDL.

93
Q

what enzyme catalyze the formation from testosterone –> estradiol? what group of enzymes does it belong to?

A

aromatase.

CYP 450 superfamily of monooxygenases

94
Q

what causes phenylketonuria?

A

deficiency in Phe hydroxylase

95
Q

which amino acids have negative charge at ph=7?

A

Asp, Glu

96
Q

which amino acids have no charge at ph=7?

A

Tyr, Ser, Cys

97
Q

which amino acids have positively charged (polar) side chains at pH=7?

A

Lys, Arg, His

98
Q

What are the essential AA?

A

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

Just remember: I Like To Teach His Mad Vets Lumbar Puncture

99
Q

what is the turnover number?

A

Mol(product)/mol(enzyme) x sec

100
Q

what is in the active site of serine proteases?

A

His, Ser, Asp

101
Q

what is Km?

A

the substrate concentration, where we can measure the half of the maximum speed.

102
Q

Vmax?

A

at high substrate concentration all enzymes are in enzyme-substrate complex therefore the speed of the enzyme reaction has reached its maximum value (Vmax)

103
Q

inhibitors of F-1,6 BPase

A

AMP/ADP and Fru-2,5-BP

104
Q

Glutathione consist of which AAs?

A

Glu-Cys-Gly

105
Q

Which protein can regulate/phosphorylate the CFTR channel?

A

cAMP dependent protein kinase

106
Q

which enzymes are needed to make dihydroorotate from Gln and Asp?

A

CPS II
Asp transcarbamoylase
Dihydroorotase

107
Q

write the reaction for fatty acid activation

A

S: Fatty acid+ATP+Hs-CoA
P:acyl-Coa + AMP + 2Pi
E: Acyl Coa synthase

108
Q

for the testosterone receptor, which has the highest affinity, testosterone or dihydrotestosterone

A

Dihydrotestosterone

109
Q

Probability for an ionchannel

A

can range from 0 to 1

110
Q

Von Gierkes disease

A

Glycogen storage disease

Glucose-6- phosphatase

111
Q

List 3 regulators for HMG-Coa reductase

A

Statins
Cholesterol (neg.feedback via Serb-Scap)
AMP activated protein kinase.

112
Q

What is the function of SR-B1?

A

Scavenger receptor. Involved in uptake of CE from HDL

113
Q

List the mechanism which can cause an increase in intracellular Ca level and name the molecules responsible for this.

A

IP3, Strophantine
Ach >IP3>increased Ca2+
Strophantine inhibits NA-K ATPase
Na-Ca reversal

114
Q

Name 2 eicosanoids

A

Thromboxane A2
PGE1
PCI2

115
Q

At least two function of peroxisomes

A
  1. Beta oxidation of very long chain fatty acids
  2. Oxidation of alchohol to acetaldehyde
  3. Production of plasmalogen (in myelin)
  4. Contains catalase which oxidizes H2O2
116
Q

Causes for increased free FA in serum:

A

Diabetes
Starvation
Heavy exercise

117
Q

Targeted channel protein in Myasthenia Gravis

A

nicotinic Ach receptor at NMJ

118
Q

Which are the most important ligands of nuclear receptors?

A

Mineralocorticoid, glucocorticoid, progesterone, androgen, estrogen, drugs

119
Q

Which are the three most common types of DNA binding domains found in intracellular receptors?

A
  1. Zinc finger binding domain
  2. Leucine zipper
  3. Helix-turn- helix
120
Q

Name at least 3 serine protease examples

A

Chymotrypsin, Trypsin, Elastase

121
Q

What enzymes are deficient in hyperurocemia

A
  1. Glucose-6-phosphatase deficiency
  2. HGPRT: hypoxanthine-guanine phosphoribosyltransferase deficiency
  3. Elevated 5’-phosphoribosyl-1’-pyrophosphate synthetase (PRPP synthetase)
122
Q

If there is an excessive citrulline, which enzymes are deficient?

A

Arginosuccinate Synthetase

123
Q

Way to reduce cholesterol blood level

A
  • Statins
  • Cholestrol free diet/ lifestyle
  • Decrease LDL receptors
  • Activate LCAT
  • RESINS
124
Q

What enzyme deficiency causes immunodeficiency?

A

ADA : Adenosine Deaminase

125
Q

Monosaccharide unit and bond type of lactose, glycogen, sucrose

A

Glycogen: glucose- glucose a(1>4) + braches a(1>6)
Lactose: glucose – galactose b(1>4)
Sucrose: glucose- fructose a(1>b2)

126
Q

Which enzymes do CYP11B2 encodes for?

A

11-OHase, 18OHase, DH aldosterone synthase

127
Q

Which enzymes do CYP11B1 encodes for?

A

11-hydroxylase

128
Q

Which enzymes do CYP17A1 encodes for?

A

17OHase and 17,20 lyase

129
Q

What are cytochromes P450 involved in?

A
  1. production of steroid hormones
  2. metabolism of FA, prostaglandins, leukotriene and retinoids.
  3. inactivation of therapeutic agents.
  4. conversion of chemical to highly reactive molecules that may produce unwanted cellular damage.
  5. enzyme inhibition or induction resulting in drug-drug interactions and adverse effects.
130
Q

Name 3 AA that can form pyruvate.

A

CYS, SER, ALA

131
Q

Which enzymes functions in both glycolysis and gluconeogenesis?

A

phosphoglucoisomerase, aldolase B+A, glyceraldehyde 3-P, phosphoglycerate kinase, phosphoglycerate mutase, enolase

132
Q

What are the irreversible steps in glycolysis? (name the enzymes)

A

HK/GK, PFK1, pyruvate kinase

133
Q

what are the enzymes for gluconeogenesis?

A

Pyruvate carboxylase, PEPCK, fructose-1-phosphatase, glucose-6-phosphatase

Y biochem final (3 decks)

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