Brainscape's Knowledge GenomeTM

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


See full index

unit 6: MCP > one carbon metabolism (16) > Flashcards

one carbon metabolism (16) Flashcards

1
Q

what is the precursor for:
dopamine
epi
norepi

A

tryosine

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

what is the precursor for:
melanin
thryoxine

A

all trosine

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

what is the precursor for:
GABA
histidine

A

GABA- glutamate

histidine-histamine

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

what is the rate limiting step in the formation of Dopa?

A

tyrosine hydroxylation

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

what cofactor does tyrosine hydroxylase require?

A

tetrahydrobiopterin

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

what enzyme degrades catecholamines?

A

monoamine oxidase (MAO)

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

what enzyme does the conversion of dopamine to norepi?

A

dopamine b-hydroxylase

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

what 2 things does the enzyme dopamine b- hydroxylase require?

A

ascorbate (vit C) and molecular oxygen

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

what enzyme is need for norepi methylation to make epinephrine? what compound acts as the methyl donor?

A

enzyme: phenylethanolamine N methyltransferase

SAM is methyl donor

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

what is disease is the result of a defect in the melanin producing pathway?

A

albinism

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

what vitamin deficiency can result form a deficiency of tryptophan?

A

niacin deficiency- pellagra

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

true or false

glutamate decarboxylase is a pyridoxal phosphate dependent enzyme

A

true

needed to make GABA

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

what enzyme catalyzes the formation of histidine?

A

histidine decarboxylase

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

what does histidine decarboxylase require?

A

pyridoxal phosphate

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

list 4 reasons why the body needs single carbon fragments

A

o Formation of methionine form homocysteine
o Biosynthesis of purines
o Biosynthesis of pyrimidines
o Biosynthesis of glycine from CO2 and NH4+ by glycine synthase

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

what carrier is able to carry the most oxidized one carbon group? what is “the most oxidized one carbon group”?

A

biotin carrying CO2

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

when does THF act as a 1 carbon acceptor?

A

in degradative reactions

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

when does THF act as a 1 carbon donor?

A

in biosynthetic reactions

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

what precursor is the production of THF depend on?

A

dietary folate

20
Q

what part of THF are humans unable to synthesize?

A

the pterin ring

21
Q

what form of folate is normally seen in the diet?

A

polyglutamines with the glutamate moieties attached in y-peptidyl linkages

22
Q

is folate normally in the oxidized or reduced state before absorption?

A

oxidized state

23
Q

what enzyme is used to reduce folic acid to THF?

A

dihydrogolic acid reductase

24
Q

what is the name of the THF in the most reduced state?

A

N-5 methyl THF

25
Q

what is the name of the THF in the most oxidized state?

A

N-5 formyl THF
N-5 formino THF
N-5,N-10 methenyl THF

26
Q

what is the name of the THF in the intermediate state?

A

N-5,N-10 methylene THF

27
Q

what is the only reaction to use N5-methyl THF?

A

for the formation of methionine

28
Q

what reaction is the main source for making N5, N10-methlene THF

A

the interconversion of serine and glycine

29
Q

what are 3 drug classes that can cause folate deficiency?

A
  1. oral contraceptives
  2. barbiturates: impairs absorption & utilization
  3. methotrexate: antimetabolite used in cancer chemo
30
Q

what are the two main drugs that are considered “anti folates”?

A

aminopterin

methotrexate

31
Q

list 5 important methylation reactions that require SAM

A
  • Norepi→epi
  • Guanidinoacetate→creatine
  • Acetylserotonin→melatonin
  • Phosphatidylethanolamine to phosphatidylcholine
  • Methaylation of DNA
32
Q

what enzyme catalyzes the reaction of the regeneration of methionine from homocysteine?

A

homocysteine methyltransferase

33
Q

what 2 cofactors does homocysteine methyltransferase use?

A

N5 methyl THF

B12

34
Q

what disease process is elevated levels of homocysteine correlated with?

A

increased risk of athrosclerosis

35
Q

vitamin supplementation with what 3 compounds has been shown to reduce the levels of homocysteine?

A

B12
folate
pyridoxal phosphate

36
Q

what enzyme catalyzes the reaction:
homocysteine & serine condensing to form cystathionine?
what is the cofactor for this enzyme?

A

cystathionine synthase

cofactor: pyridoxal phosphate

37
Q

what disease is caused by a deficiency in the enzyme cystathionine synthase?

A

homocystinuria

38
Q

people with homocystinurea have a higher risk of ____ and a lower risk of _____

A

higher risk of heart attacks

lower risk of colon cancer

39
Q

what version of cobalmin is seen in the MMAM reaction?

A

the adenosyl version

40
Q

what version of cobalamin is seen in teh HMT reaction?

A

hydroxyl version

41
Q

what two reactions in the body require cobalamin?

A
  1. Conversion of L-methylmalonyl coA to succinyl coA

2. the action of homocysteine methyltransferase

42
Q

what type of anemia does a deficiency in THF and B12 lead to?

A

megablastic anemia aka pernicious anemia

43
Q

what is a B12 deficiency associated with?

A

demyelination and degeneration of spinal cord

44
Q

what is usually the cause of a B12 deficiency?

A

a problem with intrinsic factor in the gut

45
Q

what is the name of the transporter for B12?

A

transcobalamine

46
Q

in the folate trap, what form is THF getting stuck in?

A

in the N5 methyl form (the most oxidized form)

47
Q

if a person is in a “folate trap” what does it manifest as?

A

anemia

unit 6: MCP (17 decks)

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