Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Step 1 prep > Biochem > Flashcards

Biochem Flashcards

1
Q

Histones are rich in what two amino acids?

A

Lysine and argenine (makes them positively charged)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which is the only histone not found in the nucleosome core?

A

H1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which histones make up the nucleosome core?

A

H2A, H2B, H3, H4 (each x2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does histone methylation affect gene transcription?

A

Methylation represses DNA transcription

“Methylation Mutes DNA”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does Histone Acetylation affect gene transcription?

A

“Acetylation Activates DNA”

Relaxes DNA coiling, allowing for transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does Leflunomide inhibit Pyrimidine base synthesis?

A

Inhibition of Dihydroorotate DH, which is responsible for the conversion of Carbamoyl phosphate into Orotic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does Hydroxyurea inhibit pyrimidine base synthesis?

A

Inhibition of Ribonucleotide reductase, which is responsible for the conversion of UDP into dUDP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does Methotrexate inhibit pyrimidine synthesis?

A

Inhibition of Dihydrofolate Reductase, which reduces DHF into THF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does Trimethoprim (TMP) inhibit pyrimidine synthesis?

A

Inhibition of Dihydrofolate Reductase, which reduces DHF into THF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does Pyrimethamine inhibit pyrimidine synthesis?

A

Inhibition of Dihydrofolate Reductase, which reduces DHF into THF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does 5-Flourouracil (5-FU) inhibit pyrimidine synthesis?

A

Inhibition of Thymidylate sythase, which converts dUMP into dTMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the RLS for pyrimidine synthesis?

A

Carbamoyl phosphate synthetase II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the precursor for 6-Mercaptopurine?

A

Azathioprine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does 6-MP inhibit?

A

Purine base synthesis (PRPP–>IMP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does Mycophenolate inhibit purine base synthesis?

A

Inhibition of IMP DH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does Ribavirin inhibit purine synthesis?

A

Inhibition of IMP DH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Deamination of which base gives uracil?

A

Cytosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why would a molecule with greater GC:AT ratio have a higher melting point?

A

G&C connect with 3 H bonds, A&T connect with 2 H bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What 5 substances are required to make a purine?

A

Glycine, Aspartate, Glutamine (GAG)

Tetrahydrofolate, CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What substances are required to make a pyrimidine?

A

Aspartate, Carbamoyl phosphate (glutamine+ATP+CO2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Ribonucleotide reductase is an enzyme involved in the synthesis of what? What drug inhibits it?

A

Pyrimidine synthesis, Hydroxyurea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Thymidylate synthase is an enzyme involved in the synthesis of what? What drug inhibits it?

A

Pyrimidine synthesis, 5-FU

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Dihydrofolate reductase is an enzyme used for the synthesis of what? What drugs inhibit it?

A

Pyrimidine synthesis; Methotrexate, Trimethoprim, Pyrimethamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Orotic aciduria is caused by a mutation in what enzyme?

Pt has high orotic acid and ammonium levels

A

UMP synthase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which GLUT receptors require insulin for glucose uptake and where are they found?

A

GLUT-4

-Skeletal muscle, Adipose tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which GLUT transporter is responsible for fructose uptake in the GI tract?

A

GLUT-5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

RLS of Glycolysis

A

PFK-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

RLS of Gluconeogenesis

A

Fructose 1,6 bisphosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

RLS of TCA cycle

A

Isocitrate DH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

RLS of Glycogenesis

A

Gycogen synthase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

RLS of Glycogenolysis

A

Glycogen phosphorylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

RLS of HMP shunt

A

Glucose-6-phosphate DH (G6PD)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

RLS of de novo Pyrimidine synthesis

A

Carbamoyl Phosphate Synthetase II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

RLS of De novo Purine synthesis

A

Glutamine-phosphoribosylpyrophosphate (PRPP) amidotransferase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

RLS of Urea cycle

A

Carbamoyl Phosphate Synthetase I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

RLS of fatty acid synthesis

A

Acetyl-CoA carboxylase (ACC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

RLS of fatty acid oxidation?

A

Carnitine acyltransferase I

38
Q

RLS of Ketogenesis

A

HMG-CoA synthase

39
Q

RLS of Cholesterol synthesis

A

HMG-CoA reductase

40
Q

Pt with painful muscle cramps, myoglobinuria (red urine) with strenuous exercise and arrhythmia from electrolyte abnormalities

A

McArdle Dz (glycogen storage dz type V)

  • Deficiency of Glycogen phosphorylase in muscle cells
  • Can’t break down glycogen’s alpha 1,4 bonds
41
Q

What enzyme is deficient in McArdle dz?

A

Glycogen phosphorylase (breaks down alpha 1,4 bonds)

42
Q

Severe fasting hypoglycemia, elevated lactate in blood, hepatomegaly. Liver biopsy shows elevated glycogen in the liver cells

A

Von Gierke dz (glycogen storage dz Type I)

-Deficiency in Glucose-6-phosphatase (G6P=>glucose)

43
Q

What is the enzyme deficient in Von Gierke dz?

A

Glucose-6-phosphatase

44
Q

Milder form of type I glycogen storage dz with normal lactate

A 
Cori dz (Type III)
-lack of debranching enzyme (alpha1-6 bonds)
45
Q

Glycogen storage dz leading to cardiomyopathy and early death

A 
Pompe dz (type II)
-Lack of lysosomal alpha-1-4-glucosidase
46
Q

RLS of glycogen synthesis?

A

Glycogen synthase

47
Q

RLS for glycogenolysis?

A

Glycogen phophorylase

48
Q

What enzyme converts glucose-6-phosphate to glucose?

A

Glucose-6 phosphatase

49
Q

Glycogen phosphorylase deficiency

A

McArdle dz

50
Q

Glucose-6-phosphatase deficiency

A

Von Gierke dz

51
Q

Lactic acidosis, hyperlipidemia, hyperuricemia (gout)

A

Von Gierke dz

52
Q

Alpha 1,6 glucosidase deficiency (debranching enzyme)

A

Cori dz

53
Q

Alpha 1,4 glucosidase deficiency

A

Pompe dz

54
Q

Cardiomegaly

A

Pompe dz (infantile)

55
Q

Diaphragm weakness leading to respiratory failure

A

Pompe dz (adult)

56
Q

Increased glycogen in liver, severe fasting hypoglycemia

A

Von Gierke dz

57
Q

Hepatomegaly, hypoglycemia, hyperlipidemia (normal kidneys, lactate and uric acid)

A

Cori dz

58
Q

Painful muscle cramps, myoglobinuria with strenuous exercise

A

McArdle dz

59
Q

Severe hepatosplenomegaly, enlarged kidneys

A

Von Gierke dz

60
Q

What’s the RLS of the HMP shunt (pentose-phosphate) pathway?

A

Glucose-6-phosphate Dehydrogenase (G6PD)

61
Q

What is G6PD usually used for?

A

Generation of NADPH

62
Q

How does a deficiency of G6PD result in hemolytic anemia?

A

G6PD generates NADPH which is used by Glutathione Reductase to reduce Glutathione (GSH). Glutathione is used by Glutathione peroxidase to detoxify free radicals and peroxides.
Without G6PD, RBC are highly susceptible to oxidative damage and will lyse in response to oxidative stress

63
Q

What enzyme is deficient in classic galactosemia?

A

Galactose-1P Uridyltransferase

-failure to thrive, cataracts, hepatomegaly, jaundice, mental retardation

64
Q

Deficiency of Galactokinase

A

Galactokinase deficiency (feygit)

65
Q

Deficiency of Aldolase B

A

Fructose intolerance

66
Q

Deficiency of lactase

A

Lactose intolerance

67
Q

Deficiency of Galactose-1P Uridyltransferase deficiency

A

Classic Galactosemia

68
Q

Deficiency of Fructokinase

A

Essential fructosuria

69
Q

What is Apo B-48 used for?

A

Chylomicron secretion from enterocyte to lymphatic system

70
Q

What is Apo B-100 used for?

A

Liver packages VLDL with Apo B-100 for excretion into system (so cells can pull FFA off of it)
-Apo B-100 found on VLDL, IDL, LDL

71
Q

What is the purpose of Apo E?

A

Mediates extra remnant uptake

72
Q

What’s the purpose of Apo A-1?

A

Found on HDL, Activates LCAT (puts cholesterol from tissue cells onto HDL)

73
Q

What’s the purpose of Apo C-II?

A

Cofactor for Lipoprotein lipase (LPL)

-LPL pulls FFA off of chylomicrons and VLDL and puts it into tissue

74
Q

What is the RLS for cholesterol synthesis?

A

HMG-CoA reductase

75
Q

What is cholesterol made from in the liver?

A

Acetyl-CoA

76
Q

What is the RLS for Ketone synthesis?

A

HMG-CoA Synthase

77
Q

What is the RLS for Fatty acid synthesis?

A

Acetyl-CoA Carboxylase

-FA synthesis occurs in the cytoplasm

78
Q

What is the RLS for FA degradation?

A

Carnitine acyltransferase-1 (carnitine palmitoyl transferase 1)

79
Q

What deficiency causes familial hypercholesterolemia?

A

LDL receptor deficiency

80
Q

Activates LCAT

A

Apo A1

81
Q

Mediates Chylomicron secretion

A

Apo B48

82
Q

Binds to LDL receptor

A

Apo B100

83
Q

Cofactor for lipoprotein lipase

A

Apo CII

84
Q

Mediates uptake of remnant particles

A

Apo E

85
Q

Mediates VLDL secretion

A

Apo B100

86
Q

What are the essential amino acids?

A 
"PVT TIM HaLL"
Phenylalanine
Valine
Threonine
Tryptophan
Isoleucine
Methionine
Histidine
Leucine
Lysine
87
Q

Classic basic AAs

A

Lysine, argenine (both have an extra ammonia group)

Histidine

88
Q

Which of the basic AAs are found in high concentrations in histones?

A

Argenine and Lysine

-Their positive charges allow for interaction with (-) DNA

89
Q

Acidic AAs

A

Aspartate, Glutamate (Aspartic acid, glutamic acid)

(-) charge at body pH

90
Q

What’s the AA precursor for Epinephrine?

A

Phe=>Tyrosine=>DOPA=>Dopamine=>NE=>Epi

91
Q

What amino acids build up in Maple Syrup urine dz?

A 
"I LoVe maple syrup"
Isoleucine
Leucine
Valine
(Branched chain AAs)
92
Q

What enzyme is deficient in Maple syrup urine dz?

A

alpha Ketoacid DH

Step 1 prep (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions