TCA cycle Flashcards Preview

Biochem 2 > TCA cycle > Flashcards

Flashcards in TCA cycle Deck (77)
Loading flashcards...
1
Q

fates for pyruvate (4)

A

(1) TCA
(2) lactate
(3) oxaloacetate
(4) alanine

2
Q

Energy Bookkeeping:

Glycolysis

A

2 NADH

2 ATP

3
Q

Energy Bookkeeping:

pyruvate DH

A

2 NADH

4
Q

Energy Bookkeeping:

TCA cycle

A

I cycle:
3 NADH
1 FADH2
1 GTP

5
Q

each NADH yields ____ ATP

A

2.5

6
Q

Each FADH yields ___ ATP

A

1.5

7
Q

How many ATP is produced in the end of aerobic

A

32/38

8
Q

If NADH from cytosolic glycolysis is transported via the glycerol-phosphate shuttle then only _____ ATP is produced

A

30/36

9
Q

Metabolic node

A

TCA cycle

10
Q

pyruvate is transported into the

A

mitochondria

11
Q

where does oxidative metabolism take place w/in mito?

A

matrix

12
Q

pytuvate DH rxn is an

A

irreversible process

13
Q

Pyruvate is made into acetyl-coA with what enzyme and cofactor and what is the product

A

the rxn is catalyzed by pyruvate DH with NAD+ as a cofactor

  • CO2 is released
14
Q

What is so special of CoA?

A

the sulfur bond

15
Q

Overall Rxn of the pyruvate DH rxn.

A

[Pyruvate] + [HSCoA ]+ [NAD+]—-> [AcCoA] + [CO2] + [NADH] + [H+]

16
Q

coenzyme on E1 of pyruvate DH

A

Thiamine Pyrophsophate

17
Q

Thiamine is derived from

A

Vit. B

18
Q

thiamine binds to pyruvate on

A

thiazole ring

19
Q

E1 releases

A

CO2

20
Q

obtained from enriched cereals, grains, pork, legumes, seed, nuts

A

Vit. B

21
Q

Deficiency of thiamine leads to

A
  • wernicke’s
  • wet beri
  • dry beri
22
Q

wet beri

A

cardiovascular

23
Q

dry beri

A

muscle weakness

24
Q

A young adult is seen with symptoms of fatigue and muscle cramps. The patient is diagnosed to have a thiamine deficiency. Which of the following metabolic acids is the most likely to accumulate under these circumstances?

A. Oxaloacetate
B. Succinate
C. Isocitrate
D. Malate
E. Pyruvate
A

E. Pyruvate

25
Q

active arm on E2 of pyruvate DH

A

lipoate

26
Q

riboflavin is derived from

A

Vit. B2

27
Q

coenzyme on E3 of pyruvate DH

A

FAD

28
Q

FAD

A

accepts electrons from lipoate onto flavin ring

29
Q

riboflavin deficiency leads to

A

Chielosis and Glossitis

30
Q

Pyruvate DH is inhibited by

A

Phosphorylation

31
Q

factors that promote dephosphorylation of PDH

A

insulin and calcium

32
Q

PDHA1, x-linked

A

lactic acidosis

33
Q

PDHA1 tx.

A
  • cofactor (B1/lipoic acid) supplementation
  • ketogenic dieat
  • bicarbonate/sodium citrate
  • dichloroacetate that reduces phosphorylation of PDH
34
Q

Which two enzymatic steps in the TCA cycle result in production of CO2 through oxidative decarboxylation?

A. Aconitase and pyruvate dehydrogenase
B. Citrate synthase and isocitrate dehydrogenase
C. Isocitrate dehydrogenase and alpha-ketoglutarate dehydrogenase
D. Pyruvate dehydrogenase and succinyl-CoA synthetase
E. Succinate dehydrogenase and malate dehydrogenase

A

C. Isocitrate dehydrogenase and alpha-ketoglutarate dehydrogenase

35
Q

glutamine can enter the TCA cycle through

A

alpha-ketoglutarate

36
Q

speterospecifity enzyme in the TCA cycle

A

aconitase

37
Q

alpha-ketoglutarate DH is sensitive to ____ because it has the same coenzymes as PDH

A

arsenic

38
Q

citrate inhibits

A

PFK1

39
Q

An increase in which of the following ratios causes an increase in the activity of regulated enzymes of the TCA cycle?

A. 	 acetylCoA/pyruvate
B. 	ATP/ADP
C. 	NAD+/NADH
D. 	NADP+/NADPH
E. 	 pyruvate/lactate
A

C. NAD+/NADH

40
Q

mutations associated with a variety of tumros

A

isocitrate DH

41
Q

mutations that cause a predisposition to cutaneous and uterine leiomyomas as well as kidney cancers

A

Fumarase

42
Q

mutations associated with phaeochromocytoma

A

succinate DH

43
Q

Pantothenic B5

A

burning feet syndrome

44
Q

Pyridoxine B6

A

stomatitis, chielitis, irritability

45
Q

Biotin

A

Seborrhea

46
Q

lipoamide

A

Dihydrolipoamide DH mutations

47
Q

who cannot cross the mitochondrial membrane

A
  • OAA

- Acetyl-CoA

48
Q

PDC has ____ subunits and ____ coenzymes

A

PDC has 3 subunits and 5 coenzymes

49
Q

trivalent arsenic poisoning targets

A

lipoate

50
Q

Hydroxyethyl-TPP reacts with

A

lipoate on E2

51
Q

hydroxyethyl becomes acetyl to form ________ & other S is reduced to _____

A

hydroxyethyl becomes acetyl to form thioester & other S is reduced to S-H

52
Q

CoA-SH attacks _____ and takes Acetyl to form _______

A

CoA-SH attacks thioester and takes Acetyl to form Acetyl-CoA

53
Q

E3 of PDC helps to regenerate _______ on Lipoate of E2

A

disulfide bond

54
Q

FAD has a _____ molecule and it is derived from ________

A

FAD has a flavin molecule and it is derived from Vitamin B2 (riboflavin)

55
Q

Vitamin B2 deficiency gives rise to

A

Glossitis and chielosis

56
Q

pyruvate DH is inhibited by ________ and ________

A

phosphorylation and product inhibition

57
Q

PDC is activated by kinase which is inhibited by _____ and ______ and activated by _______

A

PDC is activated by kinase which is inhibited by substrates and ADP and activated by products

58
Q

PDC deficinecy tx. (3)

A

(1) high fat/low carb-ketogenic
(2) carnitine supplements
(3) NaCO3- helps with Lactic Acidosis

59
Q

Produce reduced coenzymes: M.I.A

A
  • malate DH: NADH
  • isocitrate DH: NADH/CO2
  • alpha-ketoglutarate DH: NADH/CO2
60
Q

succinate DH produces

A

FADH2

61
Q

synthase/synthetase makes

A

CoA

62
Q

Succinyl-CoA synthetase has substrate level phosphorylation to make

A

GTP

63
Q

intestinal epithelium uses _____ as primary fuel source

A

glutamate

64
Q

can be converted to aspartate/asparagine

A

OAA

65
Q

used in heme synthesis

A

succinyl-CoA

66
Q

used to convert to Glutamate/glutamine

A

alpha-ketogluturate

67
Q

used to make FAs and Sterols

A

Citrate

68
Q

Converted to Pyruvate

A

Malate

69
Q

glutamate can be used for

A

purines

70
Q

OOA can be converted to _____ then to ______

A

To PEP and the nto Glucose

71
Q

aspartate/asparagine used for

A

purines/ pyrimidines

72
Q

TCA enzymes are

A

optically active

73
Q

alpha-ketoglutarate DH is sensitive to

A

trivalent arsenis poisoning

74
Q

______ can pass mitochondrial barrier, thus can cross to ______ to inhibit _____ and inhibit _________ creation

A

Citrate can pass mitochondrial barrier, thus can cross to cytoplasm to inhibit PFK1 and inhibit Acetyl-CoA

75
Q

anaplerotic pathway increases the ____ of the TCA cycle

A

Rate

76
Q

succinate DH linked to

A

endocrine tumors

77
Q

fumarase mut. cause predisposition to

A

cutaneous/uterine leiomyomas and kidney cancer