In TCA cycle, substrate level phosphorylation takes place during the conversion of

Options

(a) Oxaloacetic acid to citric acid
(b) Succinyl CoA to succinic acid
(c) Succinic acid to fumaric acid
(d) Fumaric acid to malic acid

Correct Answer:

Succinyl CoA to succinic acid

Explanation:

Succinyl-CoA is acted upon by enzyme succinyl CoA synthetase thiokinase to form succinate (a 4 carbon component). The reaction releases sufficient energy to form ATP (in plants) or GTP (in animals). GTP can form ATP through a coupled reaction.