Question

At the end of glycolysis, the six-carbon compound ultimately changes into-

• A. acetyl-Co­A
• B. ethyl alcohol
• C. ATP
• D. pyruvic acid

Answer 1

The correct option is D

pyruvic acid

The correct option is D.

Explanation of correct option:

1. Glycolysis is a process in which glucose is partially oxidized to form two molecules of pyruvic acid.
2. This pathway occurs in the cytoplasm of both prokaryotic and eukaryotic cells. Moreover, this process does not require any oxygen.
3. The pyruvic acid produced in this pathway can be utilized in three ways- lactic acid fermentation, alcoholic fermentation, and aerobic respiration.
4. At the end of the glycolysis pathway, glucose (six-carbon compound) ultimately changes into pyruvic acid (three-carbon compound).

Explanation of incorrect option:

Option A:

The pyruvic acid produced in glycolysis undergoes oxidative decarboxylation in the mitochondrial matrix; resulting in the formation of acetyl-CoA.

Option B:

In organisms like yeast, pyruvic acid is converted to CO₂ and ethyl alcohol. This process is known as alcoholic fermentation.

Option C:

In glycolysis, four ATP molecules are produced. Two ATPs are utilized in the pathway; hence there is a net gain of two ATP molecules.

Final answer:

At the end of glycolysis, the six-carbon compound ultimately changes into pyruvic acid.