Lecture 11 - TCA Cycle Flashcards
Which intermediate of the TCA cycle provides the carbon skeleton to produce a heme product?
A. Oxaloacetate
B. Citrate
C. Succinyl-CoA
D. a-ketoacids (OAA, a-KG)
C
Which intermediate of the TCA cycle provides the carbon skeleton to produce glucose?
A. Oxaloacetate
B. Citrate
C. Succinyl-CoA
D. a-ketoacids (OAA, a-KG)
A
Which intermediate of the TCA cycle provides the carbon skeleton to produce fatty acids?
A. Oxaloacetate
B. Citrate
C. Succinyl-CoA
D. a-ketoacids (OAA, a-KG)
B
Which intermediate of the TCA cycle provides the carbon skeleton to produce amino acids and nucleotides?
A. Oxaloacetate
B. Citrate
C. Succinyl-CoA
D. a-ketoacids (OAA, a-KG)
D
12 molecules of ATP are produced per TCA cycle. 9 ATP come from the __________.
A. GTP
B. FADH2
C. NADH
D. CO2
C (3 NADH produced/cycle)
12 molecules of ATP are produced per TCA cycle. 2 ATP come from the __________.
A. GTP
B. FADH2
C. NADH
D. CO2
B
12 molecules of ATP are produced per TCA cycle. 1 ATP comes from the __________.
A. GTP
B. FADH2
C. NADH
D. CO2
A
The rate-limiting step in the TCA cycle is catalyzed by __________.
isocitrate dehydrogenase
Citrate serves as a ______ allosteric regulator for phosphofructokinase-1 (glycolysis).
negative
Citrate serves as a positive allosteric regulator for ______________.
CoA carboxylase (fatty acid synthesis)
Reactions which replace intermediates in the TCA cycle are known as ___________.
anaplerotic reactions
The supply of oxidized cofactors (NAD+ and FAD) in the TCA cycle is dependent on:
the rate of respiration - which is dependent on the availability of O2 and ADP
Which is NOT an enzyme that catalyzes a TCA cycle reaction in which CO2 is lost?
A. PDH complex
B. Succinate DH
C. Isocitrate DH
D. a-ketogluterate DH
B. Succinate catalyzes a reaction in which FADH2 is formed.
Which is an enzyme that catalyzes a TCA cycle reaction in which FADH2 is formed?
A. PDH complex B. Succinate DH C. Isocitrate DH D. a-ketogluterate DH E. Succinate thiokinase
B
Which is an enzyme that catalyzes a TCA cycle reaction in which substrate-level phosphorylation occurs?
A. PDH complex B. Succinate DH C. Isocitrate DH D. a-ketogluterate DH E. Succinate thiokinase
E
Which is NOT an enzyme that catalyzes a TCA cycle reaction in which NADH is formed?
A. PDH complex (before TCA cycle) B. Succinate DH C. Isocitrate DH D. Malate DH E. All of these catalyze reactions in which NADH is formed.
E
Isocitrate dehydrogenase is allosterically inhibited by _____.
ATP
Isocitrate dehydrogenase is allosterically inhibited by _____.
ADP
In what type of energy state would citrate accumulate in the cell?
High energy state - indicated by ATP and NADH, which allosterically inhibit isocitrate DH
Two compounds that link the citric acid cycle with the respiratory chain (ETC) are:
- NADH
2. FADH2
