What is the net gain of ATP in glycolysis ?

Options

A. four
B. three
C. two
D. six

Answer

To determine the net gain of ATP in glycolysis, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Glycolysis**: Glycolysis is the metabolic pathway that converts glucose into pyruvate, producing energy in the form of ATP and NADH. It occurs in the cytoplasm of the cell.

2. **ATP Investment Phase**: In the initial steps of glycolysis, 2 ATP molecules are consumed to phosphorylate glucose and its intermediates. This is known as the investment phase.

3. **ATP Production Phase**: During the later steps of glycolysis, 4 ATP molecules are produced. This occurs through substrate-level phosphorylation.

4. **Calculating Net Gain**:
- ATP produced: 4 ATP
- ATP used: 2 ATP
- Net gain of ATP = ATP produced - ATP used = 4 - 2 = 2 ATP

5. **Conclusion**: Therefore, the net gain of ATP in glycolysis is 2 ATP molecules.

### Final Answer:
The net gain of ATP in glycolysis is **2 ATP**.

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