The amount of DNA present in a diploid cell at the end of interphase will be equivalent to:

Options

A. 2 N
B. `2 xx 2N`
C. 4 N
D. `2 xx N`

Answer

To determine the amount of DNA present in a diploid cell at the end of interphase, we need to understand the phases of interphase and how DNA replication occurs.

### Step-by-Step Solution:

1. **Understanding Diploid Cells**:
- A diploid cell (2n) contains two sets of chromosomes, one from each parent. For example, in humans, n is 23, so a diploid cell has 2n = 46 chromosomes.

2. **Phases of Interphase**:
- Interphase consists of three sub-phases: G1 (Gap 1), S (Synthesis), and G2 (Gap 2).
- During G1, the cell grows and prepares for DNA replication.
- The S phase is where DNA replication occurs, doubling the amount of DNA.
- In G2, the cell continues to grow and prepares for mitosis.

3. **DNA Replication in the S Phase**:
- During the S phase, each chromosome is replicated. Therefore, if a diploid cell starts with 2n amount of DNA, after replication, it will have 4n amount of DNA.
- However, it is more accurate to express this as 2 times 2n (2 sets of DNA, each consisting of 2n), which is equivalent to 2 * 2n.

4. **Conclusion**:
- At the end of interphase, specifically after the S phase, the amount of DNA in a diploid cell is 2 * 2n.
- Therefore, the correct answer is option **B: 2 * 2n**.