Question

How many oxidation steps are involved in aerobic respiration during acetylation and Krebs cycle?

• A. Two
• B. Four
• C. Three
• D. Five

Hint:

Remember: 1 oxidation in acetylation + 4 oxidations in Krebs cycle = 5 oxidations.

Answer 1

The Correct Option is D

Step 1: Oxidation during acetylation.
During the conversion of pyruvate into acetyl-CoA (acetylation), one oxidation step occurs where NAD$^+$ is reduced to NADH.
Step 2: Oxidation steps in Krebs cycle.
In the Krebs cycle, four oxidation steps occur where NAD$^+$ and FAD are reduced to NADH and FADH$_2$ respectively.
Step 3: Total oxidation steps.
One oxidation step during acetylation + four oxidation steps during Krebs cycle = total of five oxidation steps.
Step 4: Conclusion.
Hence, the correct answer is (D) Five.