How many molecules of NADH are produced when four molecules of phosphoglyceraldehyde are converted into four molecules of pyruvate?

Options

A. 2
B. 6
C. 8
D. 4

Answer

To solve the question of how many molecules of NADH are produced when four molecules of phosphoglyceraldehyde are converted into four molecules of pyruvate, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Process**: The conversion of phosphoglyceraldehyde (also known as glyceraldehyde 3-phosphate) to pyruvate occurs during glycolysis, specifically in the payoff phase.

2. **Identify the Key Reaction**: In glycolysis, each molecule of glyceraldehyde 3-phosphate (G3P) is converted into pyruvate through a series of reactions. During this conversion, NAD+ is reduced to NADH.

3. **Determine NADH Production per Molecule**: For each molecule of glyceraldehyde 3-phosphate that is converted into pyruvate, one molecule of NADH is produced.

4. **Calculate for Four Molecules**: If 1 molecule of G3P produces 1 molecule of NADH, then for 4 molecules of G3P, the total production of NADH will be:
\[ \text{NADH produced} = 4 \text{ molecules of G3P} \times 1 \text{ NADH per G3P} = 4 \text{ NADH} \]

5. **Conclusion**: Therefore, when four molecules of phosphoglyceraldehyde are converted into four molecules of pyruvate, a total of 4 molecules of NADH are produced.

### Final Answer:
**4 NADH molecules are produced.**

---