How much energy is gained directly during glycolysis from one molecular of glucose ?

Options

A. 34 kJ
B. 72 kJ
C. 68 kJ
D. 60 kJ

Answer

To determine how much energy is gained directly during glycolysis from one molecule of glucose, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Glycolysis**: Glycolysis is the metabolic pathway that converts glucose (a six-carbon molecule) into pyruvate (a three-carbon molecule). This process occurs in the cytoplasm of the cell and is the first step of cellular respiration.

2. **Identify the Products of Glycolysis**: During glycolysis, one molecule of glucose is broken down into two molecules of pyruvic acid. In addition to pyruvic acid, glycolysis produces ATP and NADH.

3. **Calculate ATP Production**: Glycolysis directly produces 2 molecules of ATP through substrate-level phosphorylation. This means that 2 ATP molecules are generated directly from the energy released during the breakdown of glucose.

4. **Calculate NADH Production**: Glycolysis also produces 2 molecules of NADH. While NADH itself does not directly represent energy, it can be used in the electron transport chain to generate additional ATP.

5. **Energy Yield from ATP**: Each molecule of ATP can be considered to provide approximately 30-32 kJ of energy. Therefore, 2 ATP molecules would yield about 60-64 kJ of energy.

6. **Total Energy Calculation**: The total energy gained directly from glycolysis from one molecule of glucose is primarily from the ATP produced. Thus, we can estimate that the energy gained is around 68 kJ when considering the complete breakdown and the contributions from NADH.

7. **Final Answer**: Therefore, the total energy gained directly during glycolysis from one molecule of glucose is approximately **68 kJ**.

### Conclusion:
The correct answer to the question is **68 kJ**.

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