Given below are two statements related to Kreb's cycle. Statement (I): There are four steps of oxidation in Kreb's cycle, catalyzed by dehydrogenases using NAD ^+ or FAD ^+ as the coenzyme. Statement (II): Two molecules of GTP are produced for every molecule of citric acid oxidized. In light of the above statements, choose the most appropriate answer from the options given below.

Step-by-step solution

In the Krebs cycle, there are four oxidation steps where hydrogen atoms are removed and transferred to coenzymes. These steps are catalyzed by dehydrogenases: 1. Isocitrate to -ketoglutarate ( NAD ^+ NADH + H ^+ ) 2. -ketoglutarate to succinyl-CoA ( NAD ^+ NADH + H ^+ ) 3. Succinate to fumarate ( FAD FADH ₂ ) 4. Malate to oxaloacetate ( NAD ^+ NADH + H ^+ ) Thus, Statement (I) is correct. During the conversion of succinyl-CoA to succinate, one molecule of GTP is synthesized through substrate-level phosphorylation.