In PPP, the net gain of ATP molecules for one glucose molecule is
34 ATPs
35 ATPs
36 ATPs
38 ATPs

Options

A. 34 ATPs
B. 35 ATPs
C. 36 ATPs
D. 38 ATPs

Answer

To determine the net gain of ATP molecules for one glucose molecule in the pentose phosphate pathway (PPP), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Pentose Phosphate Pathway (PPP)**:
- The PPP is a metabolic pathway that generates NADPH and ribose 5-phosphate from glucose 6-phosphate. It is important for biosynthetic reactions and for maintaining cellular redox balance.

2. **Conversion of Glucose**:
- Glucose is first converted into glucose 6-phosphate. This is the starting point of the PPP.

3. **NADPH Production**:
- During the PPP, glucose 6-phosphate is converted into gluconic 6-phosphate, releasing 6 molecules of NADPH.
- Then, gluconic 6-phosphate is converted into ribulose 5-phosphate, releasing another 6 molecules of NADPH.
- In total, 12 molecules of NADPH are produced from one molecule of glucose.

4. **ATP Yield from NADPH**:
- Each molecule of NADPH can be converted into 3 ATP molecules through oxidative phosphorylation.
- Therefore, the total ATP yield from 12 NADPH molecules is:
\[ 12 \text{ NADPH} \times 3 \text{ ATP/NADPH} = 36 \text{ ATP} \]

5. **Accounting for ATP Loss**:
- However, during the entire process, 1 molecule of ATP is consumed (lost).
- Thus, the net gain of ATP is calculated as:
\[ 36 \text{ ATP} - 1 \text{ ATP} = 35 \text{ ATP} \]

6. **Final Answer**:
- The net gain of ATP molecules for one glucose molecule in the PPP is **35 ATPs**.