Question

Which is the intermediate compound that links the end product of Glycolysis with TCA Cycle?

• A. Acetyl CoA
• B. Pyruvic Acid
• C. OAA
• D. Citric Acid

Hint:

The conversion of pyruvic acid to Acetyl CoA is catalyzed by the enzyme pyruvate dehydrogenase.

Answer 1

The Correct Option is A

The intermediate compound that links glycolysis with the TCA cycle is Acetyl CoA.

(A) Acetyl CoA - Correct: Pyruvate (glycolysis end product) is converted to acetyl-CoA by pyruvate dehydrogenase, which enters the TCA cycle.

(B) Pyruvic Acid - Incorrect: This is the direct end product of glycolysis, but requires conversion to acetyl-CoA first.

(C) OAA (Oxaloacetate) - Incorrect: This is a TCA cycle component that condenses with acetyl-CoA, not a glycolysis product.

(D) Citric Acid - Incorrect: This is the first product formed in TCA cycle after acetyl-CoA combines with OAA.

The correct answer is (A) Acetyl CoA, which serves as the crucial metabolic link between these pathways.

Answer 2

Glycolysis is the metabolic pathway that breaks down glucose (a six-carbon molecule) into two molecules of pyruvate (a three-carbon compound). This process occurs in the cytoplasm and does not require oxygen. After glycolysis, the pyruvate is transported into the mitochondria for further metabolism. The enzyme pyruvate dehydrogenase converts pyruvate into Acetyl CoA. This process is essential because Acetyl CoA is the molecule that enters the TCA cycle (Krebs cycle) for further energy production in the form of ATP. Acetyl CoA links glycolysis to the TCA cycle by donating its acetyl group to the cycle, where it combines with oxaloacetate to form citrate and initiate the cycle.

Option (A) is correct because Acetyl CoA is the intermediate compound that links glycolysis and the TCA cycle.