Question

The correct sequence in Krebs cycle is:

• A. Oxaloacetic acid $\to \alpha$-ketoglutaric acid $\to$ Isocitric acid
• B. Oxalosuccinic acid $\to$ Isocitric acid $\to \alpha$ ketoglutaric acid
• C. $\alpha$ ketoglutaric acid $\to$ Isocitric acid $\to$ Oxaloacetic acid
• D. Isocitric acid $\to \alpha$ ketoglutaric acid $\to$ Oxaloacetic acid

Answer 1

The correct option is D Isocitric acid $\to \alpha$ ketoglutaric acid $\to$ Oxaloacetic acid

Isocitric acid is converted into oxalosuccinic acid in the presence of the enzyme isocitric dehydrogenase. Now oxalosuccinic acid is converted into $\alpha$-ketoglutaric acid by the enzyme decarboxylase. After some steps, oxaloacetic acid (acceptor of acetyl CoA) is formed.