Brainscape's Knowledge GenomeTM

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


See full index

922 > TCA > Flashcards

TCA Flashcards

1
Q

What molecule is the source of the TCA cycle?

A

acetyl-CoA

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

In what part of the cell does the TCA cycle take place?

A

mitochondria

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

PDH =

A

pyruvate dehydrogenase complex

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

What enzyme provides the link between glycolysis and the TCA cycle (converts pyruvate to acteyl-CoA)?

A

PDH (pyruvate dehydrogenase complex)

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

How many subunits are there in pyruvate dehydrogenase complex (PDH)?

A

3 (E1, E2, E3)

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

Is the overall conversion from pyruvate to acetyl-CoA oxidation or reduction?

A

oxidation

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

Besides acetyl-CoA, what else does the conversion from pyruvate to acetyl-CoA yield?

A

1 mol NADH/H+ per mol pyruvate

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

What are two other names for the TCA cycle?

A

Krebs cycle, Citric acid cycle

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

TCA =

A

tricarboxylic acid

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

Does the TCA cycle require oxygen, even though it is considered part of aerobic metabolism?

A

no

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

The TCA cycle oxidizes the _______ portion of acetyl-CoA into 2 molecules of _____.

A

CH3CO and CO2

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

What is the source of oxygen in the TCA cycle if not gaseous O2?

A

water

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

How many reactions are in the TCA cycle?

A

8

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

How many reactions of the TCA cycle are energy-providing?

A

5

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

Dehydrogenases are enzymes that do what?

A

remove 2 H+ and 2e- (transfer them to a co-factor like NAD+)

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

The TCA cycle provides how many ATP equivalents?

A

12

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

What is the first enzyme of the TCA cycle (uses acetyl-CoA and oxaloacetate to make citrate)?

A

citrate synthase

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

Which enzyme is responsible for converting citrate into isocitrate (symmetric into asymmetric molecule)?

A

aconitase

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

How does aconitase perform an isomerization reaction to change citrate into isocitrate?

A

removes water from citrate, adds it back in different configuration to form isocitrate

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

Which enzyme converts isocitrate into alpha-ketoglutarate through a coupled decarboxylation/oxidation reaction?

A

isocitrate dehydrogenase

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

A coupled decarboxylation and oxidation reaction can also be called a ___________ reaction

A

dehydrogenation

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

What is the first enzyme of the TCA cycle that provides energy?

A

isocitrate dehydrogenase

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

Which enzyme complex converts alpha-ketoglutarate into succinyl-CoA?

A

alpha-ketoglutarate dehydrogenase complex

24
Q

How many co-enzymes are involved in the conversion from alpha-ketoglutarate to succinyl-CoA?

A

5

25
Q

How many moles of NADH/H+ are generated in the conversion of alpha-ketoglutarate to succinyl-CoA?

A

1

26
Q

How many moles of NADH/H+ are generated in the conversion of isocitrate to alpha-ketoglutarate?

A

1

27
Q

What is the role of thiamine pyrophosphate (TPP) co-enzyme in the conversion of alpha-ketoglutarate to succinyl-CoA?

A

binds the aldehyde made when alpha-ketoglutarate decarboxylated

28
Q

What is the role of lipoic acid co-enzyme in the conversion of alpha-ketoglutarate to succinyl-CoA?

A

transfers succinyl residue from thiamine pyrophosphate (TPP) to Co-enzyme A

29
Q

Which enantiomer of lipoic acid is the only useful form for the conversion of alpha-ketoglutarate to succinyl-CoA?

A

R

30
Q

What is the role of the FAD co-enzyme in the conversion of alpha-ketoglutarate to succinyl-CoA?

A

regenerates lipoic acid by taking 2H+ and 2e- (one at a time) from dihydrolipoate

31
Q

What is the role of NAD+ as a co-enzymes in the conversion of alpha-glutarate to succinyl-CoA?

A

takes the 2H+ and 2e- from FAD(2H) (which took them to regenerate lipoic acid) to create NADH/H+ (which is higher in energy than FAD(2H))

32
Q

What vitamin is needed in order to create Co-enzyme A?

A

pantothenate

33
Q

What vitamin is needed in order to create thiamine pyrophosphate (TPP)?

A

vitamin B1 (thiamine)

34
Q

What vitamin is needed to create FAD?

A

vitamin B2 (riboflavin)

35
Q

What vitamin is needed to create NAD+?

A

niacin (nicotinic acid)

36
Q

Succinate thiokinase is also known as what?

A

succinyl-CoA synthetase

37
Q

Can GTP be converted to ATP?

A

yes

38
Q

What is the role of succinate thiokinase in the TCA cycle?

A

cleaves thioester bond of succinyl-CoA, yields energy and succinate

39
Q

Between succinate dehydrogenase, fumarase, and malate dehydrogenase enzymes, which requires energy to work?

A

malate dehydrogenase

40
Q

Which enzyme is required to convert succinate to fumarate?

A

succinate dehydrogenase (produces FAD(2H))

41
Q

Which enzyme is responsible for converting fumarate to malate?

A

fumarase (hydration reaction, stepwise addition of water)

42
Q

Which enzyme is responsible for converting malate to oxaloacetate?

A

malate dehydrogenase

43
Q

In the TCA cycle, all but ______ kcal/mol of energy is conserved.

A

22 (efficiency factor of 90%)

44
Q

What are two other ways TCA cycle intermediates are used other than in the creation of energy?

A

precursors for some amino acids/neurotransmitters, used for gluconeogenesis/fatty acid biosynthesis/heme biosynthesis

45
Q

Refilling reactions are also called ________ reactions.

A

anaplerotic

46
Q

Why are refilling reactions needed to restore intermediates in the TCA cycle?

A

intermediates being used for various biosyntheses in the body

47
Q

What are the two major anabolic pathways that can be used to restore intermediates in the TCA cycle?

A

pyruvate carboxylase, propionyl-CoA carboxylase

48
Q

Which anabolic enzyme can be used to make oxaloacetate from pyruvate instead of acetyl-CoA?

A

pyruvate carboxylase

49
Q

Do carboxylases require ATP to work?

A

yes

50
Q

Carboxylases are dependent on what substance?

A

biotin

51
Q

What are five inhibitors of the TCA cycle?

A

NADH, acetyl-CoA, citrate, ATP, succinyl-CoA

52
Q

What are two activators of the TCA cycle?

A

Ca2+, ADP

53
Q

What is the only co-enzyme of the TCA cycle that the body can make (doesn’t need a vitamin)?

A

lipoic acid

54
Q

Why is Ca2+ an activator of the TCA cycle?

A

Ca2+ level increased when muscles contract (and contracting muscles need more energy)

55
Q

What are the two major sites of regulation in the TCA cycle? hint: rate-limiting steps of TCA cycle

A

isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase

56
Q

How is active transport of necessary enzymes into the mitochondria controlled?

A

helping proteins (heat shock, chaperone, like hsp70, hsp60, PBF)

922 (4 decks)

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