Lecture 28 - TCA Cycle Flashcards

1
Q

The f(X) portion of Acetyl-CoA is the ______.
A. Adenine molecule
B. Phosphate portion
C. Sulfated carbonyl group

A

C. Sulfated carbonyl

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2
Q

ATP production occurs in the _______ of the mitochondria.

A

Matrix

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3
Q

Electrons are transferred between compounds via what molecules?
A. CO2 and H2O
B. CO2 and FAD
C. NADH and FADH2

A

C. NADH and FADH2

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4
Q

The production of _____ from _____ is the only producer of nucleotide Triphosphates in the TCA cycle.

A

Succinate from succinylCoA

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5
Q
In oxidative phosphorylation, electrons are used to reduce \_\_\_\_\_. 
A. NAD+
B. O2
C. FADH
D. CO2
A

B. O2

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6
Q

The high energy elections formed by the TCA cycle produces _____ in the intermembrane space via the electron transport chain.

A

H+ gradient

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7
Q
Compartmentalization of the Kreb's cycle occurs by moving pyruvate into. 
A. Cytosol
B. Mitochondria
C. Nucleus
D. Golgi
A

B. Mitochondria

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8
Q

Pyruvate dehydrogenase is important in the ___________ of pyruvate. It it requires __________ as a prosthetic group.

A

oxidative decarboxylation of pyruvate; TPP

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9
Q

The dihydrolipoyl portion of pyruvate dehydrogenase is important in the ___________. It it requires __________ as a prosthetic group.

A

transfer of acetyl group to CoA; Lipoamide

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10
Q

Dihydrolipoyl dehydrogenase is important in the ___________. It it requires __________ as a prosthetic group.

A

regeneration of oxidized lipoamide; FAD

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11
Q

Catalytic co-factors are prosthetic groups for formation of acetyl-CoA by pyruvate dehydrogenase. What are the catalytic cofactors?

A

TPP; lipoic acid; FAD

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12
Q

Pyruvate dehydrogenase requires cofactors that function as substrate. What are they?

A

CoA and NAD

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13
Q

What is a “stoichiometric cofactor?

A

A cofactor that acts as a substrate

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14
Q
Production of acetyl-CoA occurs where?
A. Intermembrane space
B. Mitochondrial matrix
C. On the outer mitochondrial membrane
D. On the inner mitochondrial membrane
A

B. Mitochondrial matrix

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15
Q

Production of Acetyl-CoA from pyruvate occurs in three steps. What are they?

A

1) Decarboxylation of pyruvate to form CO2
2) Oxidation of acetyl group
3) Transfer of acetyl group to CoA

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16
Q

lipoamide is found on what domain of the PDH complex?
A. E1
B. E2
C. E3

A

B. E2

17
Q

Regeneration of the lipoamide molecule requires the addition of what cofactor?

A

FAD, which becomes FADH2

18
Q

FAD is produced after the regeneration of lipoamide. What are the other products of this reaction?

A

NADH and H+ (high e- electrons that go into the ETC)

19
Q

Draw the PDH complex. Include the stochiometric cofactors, catalytic cofactors, and the reactions.

A

Place the picture here.

20
Q
The reoxidation of the lipoamide chain occurs in what PDH subunit?
A. E1
B. E2
C. E3
D. All of the above
A

E3

21
Q
Which stoichiometric cofactor "visits" each subunit?
A. NAD+
B. FAD
C. Lipoamide
D. TPP
A

C. Lipoamide

22
Q

_____ activates pyruvate dehydrogenase phosphatases. This results in increased PDH activity.

A

ADP and pyruvate; ADP indicates a low energy charge and pyruvate is a PDH substrate

23
Q

______ acts to activate pyruvate dehydrogenase kinase, which decreases PDH activity

A

Acetyl-CoA; acetyl-CoA is an end product of PDH

24
Q

Isocitrate dehydrogenase is important to the production of isocitrate from citrate. Why is this important in the TCA cycle? What enzyme is used?

A

Citrate is NOT able to undergo the decarboxylation to alpha-KG. Isocitrate, however, is.

Aconitase is the enzyme

25
Q

(-) regulation of IDH

A

ATP; NADH (end products of TCA)

26
Q

(+) regulation of IDH

A

ADP (indicates low E*, and requires “jump-starting” TCA cycle)

27
Q

What steps produces NADH/CO2?

A

Isocitrate->alpha-ketogluterate;

alpha-ketogluterate-> succinyl-CoA

28
Q

What steps produce NADH only?

A

Malate to oxaloacetate

29
Q

What steps produce GTP?

A

Succinyl-CoA —> Succinate

30
Q

What step produces FADH2?

A

Succinate —> Fumarate

31
Q

Like PDH, alpha-ketoglutarate dehydrogenase joins the product of the reaction to ____.

A

CoA

32
Q

The final four steps of the TCA cycle are responsible for ___.

A

Regeneration of oxaloacetate

33
Q

Oxaloacetate regeneration converts a methylene in fumarate to ________ in oxaloacetate.

A

carbonyl

34
Q

High energy electrons are released from enzymes in all steps of the TCA cycle except:

A. Succinyl CoA to Succinate with ATP generation
B. Succinate to Fumarate with FADH2 production
C. Malate to Oxaloacetate with NADH production
D. Isocitrate to alpha-ketoglutarate with NADH production

A

A.

35
Q

Malate oxidation to oxaloacetate has a + deltaG. How is this overcome?

A
  • By the movement of NADH into the ETC

- By the use of oxaloacetate to form citrate (by citrate synthase)