The substrate for pentose phosphate pathway is

Options

A. Glucose 6-phosphate
B. Glucose 1-phosphate
C. Fructose 6-phosphate
D. Fructose 1-phosphate

Answer

**Step-by-Step Solution:**

1. **Understand the Pentose Phosphate Pathway (PPP)**: The PPP is a metabolic pathway that runs parallel to glycolysis and is crucial for producing NADPH and ribose-5-phosphate.

2. **Identify the Location**: The PPP occurs in the cytoplasm of the cell.

3. **Recognize the Substrate**: The key substrate for the PPP is glucose 6-phosphate. This compound is utilized at the beginning of the pathway.

4. **Examine the Options**: The question provides four options:
- Glucose 6-phosphate
- Glucose 1-phosphate
- Fructose 6-phosphate
- Fructose 1-phosphate

5. **Determine the Correct Option**: Among these options, glucose 6-phosphate is the only one that acts as a substrate for the PPP. The other options (glucose 1-phosphate, fructose 6-phosphate, and fructose 1-phosphate) do not serve as substrates for this pathway.

6. **Conclude the Answer**: Therefore, the substrate for the pentose phosphate pathway is **glucose 6-phosphate**.

**Final Answer**: Glucose 6-phosphate.

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