Question

Substrate level phosphorylation occurs during

• A. Succinic acid$\to$Fumaric acid
• B. Fumaric acid$\to$Malic acid
• C. Oxalosuccinic acid$\to \alpha -$ketoglutaric acid
• D. Succinyl $CoA\to$Succinic acid

Answer 1

The correct option is D Succinyl $CoA\to$Succinic acid

Conversion of succinyl $CoA$ into succinic acid

In case of Krebs’ cycle the step involving the conversion of succinyl $CoA$ to succinic acid yields an $ATP$ or $GTP.$

This is the only step in the Krebs’ cycle that yields a compound with high phosphoryl transfer potential through substrate-level phosphorylation.

Final answer

(D).Succinyl $CoA\to$Succinic acid