During photosynthesis when PGA is changed into phosphoglyceraldehyde, which of the following reaction occur

Options

A. Oxidation
B. Reduction
C. Electrolysis
D. Hydrolysis

Answer

**Step-by-Step Solution:**

1. **Understanding the Context**: The question pertains to the process of photosynthesis, specifically focusing on the conversion of phosphoglycerate (PGA) to phosphoglyceraldehyde (PGAL) during the Calvin cycle.

2. **Identifying the Reaction**: In the Calvin cycle, phosphoglycerate (PGA) is converted into 1,3-diphosphoglycerate (1,3-DPG) and then into phosphoglyceraldehyde (PGAL). This conversion involves several steps and the utilization of specific enzymes and molecules.

3. **Key Enzymes and Molecules**:
- The enzyme **3-phosphoglycerate kinase** catalyzes the conversion of PGA to 1,3-DPG, using ATP.
- The conversion of 1,3-DPG to PGAL is catalyzed by the enzyme **glyceraldehyde 3-phosphate dehydrogenase**.

4. **Reduction Reaction**: The conversion of 1,3-DPG to PGAL is a reduction reaction. During this process, NADPH (a reducing agent) donates electrons, which reduces 1,3-DPG to PGAL. This is characterized by the gain of electrons or hydrogen, indicating a reduction.

5. **Conclusion**: Therefore, the correct answer to the question is that the reaction occurring when PGA is converted to PGAL is a **reduction reaction**.

**Final Answer**: The correct option is **reduction**.

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