Question

The number of carbon atoms per molecule of citric acid, oxaloacetic acid and pyruvic acid respectively are _________

• A. 4, 6 and 3
• B. 6, 4 and 3
• C. 6, 3 and 2
• D. 4, 4 and 3

Hint:

Remember: Glycolysis produces 3-carbon pyruvate, while the Krebs cycle starts with 6-carbon citrate.

Answer 1

The Correct Option is B

Step 1: Understanding metabolic intermediates.
Citric acid, oxaloacetic acid, and pyruvic acid are important intermediates of cellular respiration.

Step 2: Counting carbon atoms.
Citric acid is a six-carbon compound formed by the condensation of acetyl-CoA and oxaloacetate.
Oxaloacetic acid contains four carbon atoms.
Pyruvic acid is a three-carbon compound formed during glycolysis.

Step 3: Conclusion.
Thus, the correct order of carbon atoms is 6, 4, and 3.