Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry > Citric Acid Cycle > Flashcards

Citric Acid Cycle Flashcards

1
Q

Does the TCA occur under aerobic or anaerobic conditions?

A

aerobic

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

Where does the citric acid cycle take place?

A

mitochondrial matrix

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

What is the carbon source for the citric acid cycle?

A

acetyl CoA

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

What does the oxidation of 2-carbon units in TCA produce?

A

3 NADH, 1 FADH2, 2 CO2, 1 GTP

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

What do the electrons in the TCA do?

A

reduce oxygen and generate a proton gradient. This is then used to synthesize ATP.

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

What is pyruvate from glycolysis converted into?

A

acetyl CoA.

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

What is pyruvate converted into during anaerobic conditions?

A

lactate or ethanol.

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

What does pyruvate do during aerobic conditions?

A

enters the mitochondria.

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

What are the three major components of pyruvate dehydrogenase?

A

TPP (E1), Lipoamide (E2) and FAD (E3).

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

What does TPP do?

A

oxidatively decarboxylates pyruvate.

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

What does lipoamide do?

A

transfers acetyl group to CoA

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

What does FAD do?

A

regenerates the oxidized form of lipoamide

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

What is the first step of the TCA?

A

the conversion of pyruvate to acetyl CoA.

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

The conversion of pyruvate to acetyl CoA involves what cofactors?

A

TPP, lipoic acid and FAD, as well as the stoichiometric cofactors CoA and NAD+

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

The conversion of pyruvate to acetyl CoA involves what 3 steps?

A

decarboxylation, oxidation and transfer of an acetyl group to coenzyme A.

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

Why are the three steps of the conversion of pyruvate to acetyl CoA coupled together?

A

To conserve energy to drive formation of NADH and CoA.

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

What is the first step in the conversion of pyruvate to acetyl coa?

A

TPP + pyruvate = hydroxyethyl TPP

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

what is the second step in the conversion of pyruvate to acetyl CoA?

A

hydroxyethyl TPP + lipamide -> acetyllipoamide (E1)

19
Q

What is the third step in the conversion of pyruvate to acetyl CoA?

A

coenzyme A + acetyllipoamide = acetyl CoA + Dihydrolipoamide (E2)

20
Q

In order to conduct another reaction, what must dihydrolipoamide be reconverted into?

A

lipoamide

21
Q

How is pyruvate dehydrogenase regulated?

A

allosterically and by reverse phosphorylation.

22
Q

What inactivates E2?

A

high acetyl CoA.

23
Q

The products of the TCA increase phosohrylation of what enzyme?

A

PDH.

24
Q

What enzyme phosphorylates PDH and makes it inactive?

A

kinase

25
Q

What enzyme dephosphorylates PDH and makes it active?

A

phosphatase

26
Q

ADP and pyruvate activate what enzyme regulator of PDH?

A

phosphatase; it works by activating PDH

27
Q

Does TCA or glycolysis produce more energy from glucose?

A

TCA

28
Q

What enzyme links glycolysis to the citric acid cycle.

A

pyruvate dehydrogenase

29
Q

The reaction of isocitrate to alpha-ketoglutarate produces what?

A

NADH; this is facilitated by isocitrate dehydrogenase.

30
Q

The reaction of alphaketoglutarate to succinyl coa produces what?

A

NADH; this is facilitated by alpha-ketoglutarate dehydrogenase complex

31
Q

The reactionof succinyl Coa to succinate produces what?

A

GTP; this is facilitated by succinyl CoA synthetase. This is also the only step that produces GTP.

32
Q

The reaction of succinate to fumarate produces what?

A

FADH2. This is facilitated by succinate dehydrogenase.

33
Q

The reaction of malate to oxaloacetate produces what?

A

NADH; this is facilitated by malate dehydrogenase.

34
Q

What is the role of succinate dehydrogenase?

A

It produces FADH2. It is not released from the enzyme, but electrons are passed directly to coenzyme q in the electron transport chain.

35
Q

What step of the the citric acid cycle is irreversible?

A

the conversion of pyruvate to acetyl CoA.

36
Q

If acetyl CoA is not used in the citric cycle, what can it also be used for?

A

lipid production.

37
Q

What dictates PDH activity?

A

energy charge. At high energy, PDH is negatively inhibited. At low energy, pyruvate and ADP activate PDH.

38
Q

Phosphatases are stimulated by what ion in order to initiate muscle contraction?

A

Calcium

39
Q

What activates fatty acid synthesis by activating phosphatases?

A

insulin; this increases the conversion of pyruvate to acetyl CoA.

40
Q

What is isocitrate dehydrogenase activated and inhibited by?

A

activated by ADP, inactivated by ATP and NADH.

41
Q

What is alpha ketoglutarate dehydrogenase inhibited by?

A

ATP, succinyl CoA and NADH.

42
Q

What is pyruvate dehydrogenase activated and inhibited by?

A

activated by ADP and pyruvate; inhibited by ATP, acetyl Coa and NADH.

43
Q

When energy needs are met, what are intermediates in the citric acid cycle used for?

A

the biosynthesis of other molecules.

Biochemistry (6 decks)

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