Flashcards in MCP - Cross - 2/10 - Citric Acid Cycle Deck (20)
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1
A membrane transport system is present in the inner mitochondrial membrane to transport which of the following molecules?
A. Pyruvate B. O2
C. NADH D. CO2
E. Dinitrophenol
A. Pyruvate
Remember O2 can diffuse across the membrane
2
The reaction catalyzed by aconitase can be characterized as a(n):
A. oxidative transfer
B. condensation/hydrolysis
C. oxidative decarboxylation
D. substrate-level phosphorylation
E. dehydration/hydration
E. Dehydration/hydration
3
Which of the following enzymes catalyzed a reaction sequence that illustrates the Common Intermediate Principle?
A. Adenylate kinase
B. Hexokinase
C. Fumarase
D. Succinyl-CoA synthetase
E. None of the above
D. Succinyl-CoA synthetase
4
Which of the following is not a function of the CAC?
1. Converts a number of different fuels to a common mobile fuel (NADH).
2. Breaks down glucose to pyruvate conserving the energy available as ATP and NADH
3. Serves as a final meeting place of nearly all oxidizable substrates.
4. Provides intermediates for biosynthesis.
2. is not a function of the CAC.
5
Why are mitochondria often located near structures requiring ATP?
Because this decreases the diffusion path from where ATP is made to where it is needed
6
Where does the citric acid cycle occur?
In the matrix of the mitochondria
7
Name reaction type and enzyme involved in the following:
Acetyl Coa + Oxaloacetate --> Citryl CoA --> Citrate + CoA
Reaction: Condensation and hydrolysis of the thioester
Enzyme: Citrate synthase
8
Name reaction type and enzyme involved in the following:
Citrate --> Cis Aconitase --> Isocitrate
Reaction: Dehydration and hydration
Enzyme: Aconitase
9
Name reaction type and enzyme involved in the following:
Isocitrate --> Oxalosuccinate --> alpha-ketoglutarate
Reaction: Oxidative decarboxylation
Enzyme: Isocitrate dehydrogenase
10
Name reaction type and enzyme involved in the following:
alpha-ketoglutaric acid --> Succinyl CoA
Reaction: Oxidative decarboxylation & formation of thioester
Enzyme: alpha-ketoglutarate dehydrogenase complex
11
Name reaction type and enzyme involved in the following:
Succinyl CoA --> Succinate + CoA
Reaction: Thioester cleavage w/ GTP synthesis
Enzyme: Succinyl CoA synthetase
12
Name reaction type and enzyme involved in the following:
Succinate --> Fumarate --> Malate --> Oxaloacetate
Reaction: Oxidation, hydration, oxidation (respectively)
Enzyme: Succinate dehydrogenase, fumarase, malate dehydrogenase
13
__1__ molecules of GTP are formed from 2 molecules of __2__
1. Two
2. Succinyl CoA
14
Six __1__ are formed in the oxidation of 2 molecules each of __2__, __3__ and __4__
1. NADH
2. isocitrate
3. alpha-ketoglutarate
4. malate
15
__1__ FADH2 are formed in the oxidation of 2 molecules of __2__
1. Two
2. succinate
16
How many ATP/glucose does the citric acid cycle yield?
2 (in the form of GTP)
17
Beriberi syndrome, a deficiency of vitamin B1, results in build-up of what substrate?
Pyruvate
Note than thiamine, aka TPP is vitamin B1, the prosthetic group for condensation and decarboxylation of pyruvate dehydrogenase (E1).
18
Which tissue of the eye relies solely on anaerobic metabolism instead of the CAC/ETC?
The cornea, because access to O2 would compromise the transmission of light
19
Which one of the following is a property of pyruvate dehydrogenase?
A. The enzyme contains only one polypeptide chain
B. The enzyme requires thiamine pyrophosphate as a cofactor.
C. The enzyme produces oxaloacetate from pyruvate.
D. The enzyme is converted to an active form by phosphorylation.
B. The enzyme requires thiamine pyrophosphate as a cofactor.
Pyruvate dehydrogenase converts pyruvate to acetyl-CoA, and contains multiple subunits. Thiamine pyrophosphate, lipoic acid, coA and NAD+ are all cofactors for these reactions.
20
