Question

During which stage in the complete oxidation of glucose are the greatest number of ATP molecules formed from ADP?

• A. Krebs’ cycle
• B. Glycolysis
• C. Electron transport chain
• D. Conversion of pyruvic acid to acetyl CoA

Answer 1

The correct option is C

Electron transport chain

The correct option is C.

Explanation for the correct option:

1. During aerobic respiration, the electron transport cycle produces the majority of ATP molecules.
2. The electron transport chain oxidizes NADH and FADH2, which are created during glycolysis, oxidative decarboxylation of pyruvate, and the Krebs cycle.
3. This is followed by the synthesis of ATP through chemiosmosis.
4. Oxidative phosphorylation is the name of the procedure.
5. Each revolution of the Krebs cycle results in a direct net gain of 2 ATP during glycolysis.

An explanation for the incorrect options:

Option A:

1. The primary source of energy for cells and an essential component of aerobic respiration is the tricarboxylic acid (TCA) cycle, sometimes referred to as the Krebs or citric acid cycle.
2. The cycle converts the acetyl-coenzyme A (acetyl CoA) chemical energy into the reducing force of nicotinamide adenine dinucleotide (NADH).

Option B:

1. The process by which glucose is broken down to provide energy is known as glycolysis.
2. It generates two pyruvate molecules, ATP, NADH, and water.
3. It doesn't need oxygen to happen because it happens in a cell's cytoplasm.
4. Both aerobic and anaerobic creatures experience it.

Option D:

1. Since acetyl CoA only contains two carbon atoms, whereas pyruvic acid contains three, one molecule of carbon dioxide is emitted when one molecule of pyruvic acid is transformed into one molecule of acetyl CoA.
2. It is a decarboxylation reaction as a result.

Final answer: During the electron transport chain greatest number of ATP molecules formed from ADP.