Question

During the TCA cycle, which step results in substrate-level phosphorylation?

• A. Isocitrate to α-ketoglutarate
• B. α-ketoglutarate to Succinyl-CoA
• C. Succinyl-CoA to Succinate
• D. Malate to Oxaloacetate

Hint:

Look for reactions in the TCA cycle where ATP is generated directly through substrate-level phosphorylation.

Answer 1

The Correct Option is C

Substrate-level phosphorylation occurs during the conversion of Succinyl-CoA to Succinate, where a high-energy phosphate group is transferred to ADP to form ATP. This is one of the key energy-producing steps in the TCA cycle. The other steps involve decarboxylation and electron transfer but do not directly result in ATP production via substrate-level phosphorylation.