What will be the amount of DNA in a pollen grain if its mother cell has 32 picogram DNA in `G_(2)` phase ?

Options

A. 16 pg
B. 32 pg
C. 8 pg
D. 4 pg

Answer

To determine the amount of DNA in a pollen grain when its mother cell has 32 picograms (pg) of DNA in the G2 phase, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Cell Cycle Phases**:
- The pollen mother cell (PMC) goes through several phases in the cell cycle: G1, S, G2, and M (mitosis).
- In the G2 phase, the DNA has already been replicated during the S phase.

2. **Identify the Amount of DNA in G2 Phase**:
- The problem states that the mother cell has 32 pg of DNA in the G2 phase.
- This means that the DNA has already been duplicated, so the amount of DNA in the G1 phase would have been half of this, which is 16 pg.

3. **Mitosis and Formation of Pollen Grains**:
- During the M phase, the PMC undergoes meiosis to produce pollen grains.
- Meiosis results in the formation of four haploid cells (pollen grains) from one diploid PMC.

4. **Calculate the Amount of DNA in Each Pollen Grain**:
- Since the PMC has 32 pg of DNA in the G2 phase, when it undergoes meiosis, this amount will be divided among the four pollen grains.
- Therefore, the amount of DNA in each pollen grain will be:
\[ \text{Amount of DNA in each pollen grain} = \frac{32 \text{ pg}}{4} = 8 \text{ pg} \]

5. **Conclusion**:
- The amount of DNA in one pollen grain is 8 picograms (pg).

### Final Answer:
The amount of DNA in a pollen grain is **8 pg**.

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