Question

Molecule G is a four carbon molecule which is formed from the Molecule F a tricarboxylic acid after it has gone through oxidative decarboxylations to yield G during citric acid cycle. Molecule F is formed from Molecule E which in turn is formed from Molecules C and D condensation. Molecule C is formed from the oxidative decarboxylation of Molecule A and Molecule D is formed from the oxidation of Molecule X.

1. Molecule X is:

A. Alpha-ketoglutarate

B. Oxaloacetate

C. NAD+

D. Malate

E. None of the above

2. Molecule A is:

A. Isocitrate

B. Pyruvate

C. Alpha-ketoglutarate

D. Oxaloacete

E. None of the above

3. Carboxylation of Molecule A leads to the formation of:

A. Fumarate

B. Oxaloacetate

C. PEP

D. Malate

E. None of the above

4. The oxidation of Molecule G leads to the formation of;

A. Succinate

B. Succinyl CoA

C. Fumarate

D. Pyruvate

E.None of the above

Answer 1

TCA cycle:
Occurs only in the presence of oxygen.
Occurs in the cytosol (In prokaryotes) and in the mitochondrial matrix in eukaryotes.
Primarily involved in the oxidation of acetyl CoA

A = Pyruvate
C = Acetyl CoA
D = Oxaloacetate
E = Citrate
F = Oxalosuccinate
G = Succinate
X = Malate

1. Option D is correct
X = Malate

2. Option B is correct
A = Pyruvate

3. Option B is correct
Carboxylation of pyruvate produces oxaloacetate

4. Option C is correct
Oxidation of succinate produces fumarate