Number of G - 3 - P and DHAP molecules required to regenerate 6 molecules of RuBP in Calvin cycle respectively are

Options

A. 4,6
B. 6,4
C. 6,6
D. 4,4

Answer

To solve the question regarding the number of G3P (Glyceraldehyde 3-phosphate) and DHAP (Dihydroxyacetone phosphate) molecules required to regenerate 6 molecules of RuBP (Ribulose 1,5-bisphosphate) in the Calvin cycle, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Calvin Cycle**:
- The Calvin cycle is a process in plants where carbon dioxide is converted into glucose using energy from ATP and NADPH. The key molecule involved in this cycle is RuBP.

2. **Formation of G3P and DHAP**:
- During the Calvin cycle, each molecule of RuBP combines with carbon dioxide to produce two molecules of 3-phosphoglycerate (3-PGA), which are then converted into G3P and DHAP.

3. **Molecule Production**:
- For every 3 molecules of RuBP that enter the cycle, 1 molecule of G3P is produced. This means to produce 6 molecules of RuBP, we need to produce 6 molecules of G3P.

4. **Calculating DHAP Requirement**:
- It is noted that for every molecule of G3P produced, approximately 0.66 molecules of DHAP are formed. Therefore, to find the total DHAP needed for 6 G3P:
- Total DHAP = 6 G3P × 0.66 = 3.96, which rounds to approximately 4 molecules of DHAP.

5. **Final Calculation**:
- Therefore, to regenerate 6 molecules of RuBP, we need:
- 6 molecules of G3P
- 4 molecules of DHAP

### Conclusion:
The answer to the question is that to regenerate 6 molecules of RuBP, we require:
- **6 molecules of G3P**
- **4 molecules of DHAP**