In which step of citric acid cycle, a molecule of GTP is synthesised ?

The correct answer is succinyl-CoA to succinic acid

Concept:

• The Krebs cycle, also known as the citric acid cycle or TCA (tricarboxylic acid) cycle, is a series of enzymatic reactions in the mitochondria that generates ATP through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins.
• One molecule of GTP (or ATP in certain cells) is produced directly in the Krebs cycle.
• GTP synthesis involves substrate-level phosphorylation, a process where a phosphate group is directly transferred from a substrate to ADP or GDP.
• Succinyl-CoA to succinic acid: This step involves the conversion of succinyl-CoA to succinate. The enzyme succinyl-CoA synthetase catalyzes a substrate-level phosphorylation reaction, resulting in the formation of GTP (or ATP) from GDP and Pi. This is the only step in the Krebs cycle where GTP is directly synthesized.