Identify the correct sequence of enzyme given below which participate in the regeneration phase of Calvin cycle. I Triose phosphate ismomerase II Ribulose-5-phosphate kinase III Transketolase IV Aldolase

Options

A. I,IV,III,II
B. II,IV,III,I
C. IV,I,III,II
D. III,II,I,IV

Answer

To identify the correct sequence of enzymes that participate in the regeneration phase of the Calvin cycle, we will analyze the functions of each enzyme mentioned in the question.

### Step-by-Step Solution:

1. **Triose Phosphate Isomerase (TPI)**:
- This enzyme catalyzes the interconversion of glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP).
- It is the first enzyme involved in the regeneration phase, converting G3P into DHAP.

2. **Aldolase**:
- Aldolase catalyzes the condensation of G3P and DHAP to form fructose 1,6-bisphosphate.
- This enzyme follows TPI in the sequence.

3. **Transketolase**:
- Transketolase transfers a two-carbon unit from one sugar to another, converting G3P and fructose 6-phosphate into erythrose 4-phosphate and ribulose 5-phosphate.
- This enzyme comes after aldolase in the sequence.

4. **Ribulose-5-Phosphate Kinase**:
- This enzyme phosphorylates ribulose 5-phosphate to ribulose 1,5-bisphosphate, completing the regeneration phase of the Calvin cycle.
- It is the last enzyme in the sequence.

### Correct Sequence:
Based on the functions of the enzymes, the correct order is:
1. Triose phosphate isomerase (TPI)
2. Aldolase
3. Transketolase
4. Ribulose-5-phosphate kinase

Thus, the correct sequence of enzymes is **I (Triose phosphate isomerase) → IV (Aldolase) → III (Transketolase) → II (Ribulose-5-phosphate kinase)**.

### Final Answer:
The correct answer is **I → IV → III → II**.

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