Question

All enzymes of the tricarboxylic acid cycle are located in the mitochondrial matrix except one. In prokaryotes, this enzyme is present in the cytoplasm. Identify the enzyme and its location in eukaryotes.

• A. Lactate dehydrogenase in outer mitochondrial membrane
• B. Isocitrate dehydrogenase in inner mitochondrial membrane
• C. Malate dehydrogenase in the thylakoid membrane
• D. Succinate dehydrogenase in inner mitochondrial membrane

Answer 1

The correct option is D Succinate dehydrogenase in inner mitochondrial membrane

In eukaryotes, the tricarboxylic acid (TCA) cycle takes place in the mitochondrial matrix whereas it occurs in the cytoplasm in prokaryotes. This is because prokaryotes lack mitochondria.

All enzymes of the TCA cycle are located in the mitochondrial matrix except succinate dehydrogenase which is associated with the inner mitochondrial membrane.

Succinate dehydrogenase catalyses the oxidation of succinate into fumarate in TCA cycle.