Question

Out of 38 ATP molecules produced per glucose, 32 ATP molecules are formed from NADH/ FADH₂ in

• A. Krebs Cycle
• B. Respiratory chain
• C. Oxidative decarboxylation
• D. EMP

Answer 1

The correct option is B

Respiratory chain

The correct option is B.

Explanation of the correct option:

1. The electron transport chain, often known as the "respiratory chain," is embedded in the inner membrane of the mitochondria for aerobic respiration.
2. The high-energy electrons are donated to energy carrier molecules within the membrane by the FADH₂ and NADH molecules created during glycolysis and the Krebs Cycle.

Explanations of the incorrect options:

Option A:

1. Two molecules of carbon are created per cycle, along with three molecules of NADH, one molecule of FADH₂, and one molecule of ATP or GTP.
2. Each glucose molecule generates two acetyl CoA molecules, enough for two cycles.

Option C:

1. During the oxidative decarboxylation and production of acetyl Co-A from pyruvic acid, two molecules of NADH are liberated.
2. As a result, the total amount of ATP molecules will be 2 x 3 = 6.

Option D:

1. With the help of the Embden-Meyerhof-Parnas (EMP) pathway, glucose can be used metabolically to produce ATP, NADH, and a number of biosynthetic precursors such as 3-phosphoglycerate or pyruvate.
2. In glycolysis, 2 glyceraldehyde 3-phosphate is oxidized to 1, 3-bisphosphoglycerate, which results in a net generation of 2 ATP and 2 NADH molecules.
3. The respiratory chain generates 6 ATP molecules from this 2 NADH, so the EMP route can generate a total of 8 ATP molecules.

Final answer: Out of 38 ATP molecules produced per glucose, 32 ATP molecules are formed from NADH/ FADH2 in the respiratory chain.