During the synthesis phase, if the initial amount of DNA in the cell is 15 ng, then after the synthesis phase the amount of DNA in the cell will be ……..

Options

A. 15 ng
B. 30 ng
C. 45 ng
D. 60 ng

Answer

To solve the question regarding the amount of DNA after the synthesis phase, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Synthesis Phase**:
- The synthesis phase (S phase) is a part of the cell cycle where DNA replication occurs. During this phase, each chromosome is duplicated, resulting in two copies of each DNA molecule.

2. **Initial Amount of DNA**:
- According to the question, the initial amount of DNA in the cell is given as 15 nanograms (ng).

3. **DNA Replication**:
- During the S phase, the amount of DNA doubles. Therefore, if we start with 15 ng of DNA, after replication, the amount of DNA will be:
\[ \text{Final Amount of DNA} = \text{Initial Amount of DNA} \times 2 \]
\[ \text{Final Amount of DNA} = 15 \, \text{ng} \times 2 = 30 \, \text{ng} \]

4. **Conclusion**:
- After the synthesis phase, the total amount of DNA in the cell will be 30 ng.

### Final Answer:
- The amount of DNA in the cell after the synthesis phase will be **30 ng**.