How many of the following respiratory reaction occur in the cytoplasm of a eukaryotic cell ?
(1) PGAL `rarr` 1, 3 di PGA
(2) Succinyl CoA `rarr` Succinic acid
(3) Pyruvic acid `rarr` Acetyl CoA
(4) PEP `rarr` Pyruvate
(5) Fructose 1,6 diphosphate `rarr` DHAP + 3PGAL

Options

A. (1) and (5) only
B. (1), (4) and (5) only
C. (1), (2),(3) and (5) only
D. (1) and (5) only

Answer

To determine how many of the listed respiratory reactions occur in the cytoplasm of a eukaryotic cell, we will analyze each reaction step by step.

### Step-by-Step Solution:

1. **Reaction 1: PGAL → 1,3-diphosphoglycerate**
- This reaction is part of glycolysis, which occurs in the cytoplasm of eukaryotic cells.
- **Conclusion**: This reaction occurs in the cytoplasm.

2. **Reaction 2: Succinyl CoA → Succinic acid**
- This reaction is part of the Krebs cycle (Citric Acid Cycle), which takes place in the mitochondrial matrix.
- **Conclusion**: This reaction does not occur in the cytoplasm.

3. **Reaction 3: Pyruvic acid → Acetyl CoA**
- This reaction occurs in the mitochondrial matrix, where pyruvate is converted into acetyl CoA before entering the Krebs cycle.
- **Conclusion**: This reaction does not occur in the cytoplasm.

4. **Reaction 4: PEP → Pyruvate**
- This reaction is also part of glycolysis and occurs in the cytoplasm.
- **Conclusion**: This reaction occurs in the cytoplasm.

5. **Reaction 5: Fructose 1,6-diphosphate → DHAP + 3PGAL**
- This reaction is another step in glycolysis, which occurs in the cytoplasm.
- **Conclusion**: This reaction occurs in the cytoplasm.

### Summary of Findings:
- Reactions that occur in the cytoplasm:
- Reaction 1 (PGAL → 1,3-diphosphoglycerate)
- Reaction 4 (PEP → Pyruvate)
- Reaction 5 (Fructose 1,6-diphosphate → DHAP + 3PGAL)

- Reactions that do not occur in the cytoplasm:
- Reaction 2 (Succinyl CoA → Succinic acid)
- Reaction 3 (Pyruvic acid → Acetyl CoA)

### Final Count:
Out of the five reactions, **three reactions occur in the cytoplasm of a eukaryotic cell**.

### Answer:
**3 reactions occur in the cytoplasm.**

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