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 derived from a mother cell with 32 picograms of DNA in the G2 phase, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the G2 Phase**: The G2 phase of the cell cycle is where the cell has completed DNA replication. In this phase, the DNA content is at its maximum, which is represented as 4N (tetraploid).

2. **Identify the DNA Content in the Mother Cell**: The problem states that the mother cell has 32 picograms (pg) of DNA in the G2 phase. Since this is the 4N state, we can conclude that:
- 4N = 32 pg

3. **Determine the Diploid (2N) Content**: To find the diploid (2N) DNA content, we divide the tetraploid amount by 2:
- 2N = 32 pg / 2 = 16 pg

4. **Understand the Formation of Pollen Grains**: Pollen grains are formed from microspore mother cells through meiosis. Meiosis is a reductional division that halves the chromosome number, resulting in haploid cells.

5. **Calculate the Haploid (N) Content**: Since the pollen grain is haploid (N), we need to divide the diploid content by 2:
- N = 16 pg / 2 = 8 pg

6. **Conclusion**: Therefore, the amount of DNA in a pollen grain is 8 picograms.

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

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