How many chromosomes will the diploid cell have at G1 after S and after M - phase respectively if the haploid cell has 7 chromosomes ?

Options

A. 7,7,14
B. 7,14,14
C. 14,14,14
D. 7,7,7

Answer

To solve the question regarding the number of chromosomes in a diploid cell at different phases of the cell cycle, we can follow these steps:

### Step 1: Understand the terms
- **Haploid (n)**: A cell with one set of chromosomes. In this case, it has 7 chromosomes.
- **Diploid (2n)**: A cell with two sets of chromosomes. This means it has twice the number of chromosomes as a haploid cell.

### Step 2: Calculate the number of chromosomes in the diploid cell
Since the haploid cell has 7 chromosomes:
- For a diploid cell, the number of chromosomes would be:
\[ 2n = 2 \times 7 = 14 \]
So, a diploid cell has 14 chromosomes.

### Step 3: Analyze the phases of the cell cycle
- **G1 Phase**: This is the first gap phase after cell division where the cell grows and prepares for DNA replication. The number of chromosomes remains the same as the diploid number.
- **S Phase**: This is the synthesis phase where DNA replication occurs. Although the DNA content doubles, the number of chromosomes (counted by the number of centromeres) remains the same.
- **M Phase**: This is the mitotic phase where the cell divides. Again, the number of chromosomes remains the same as in G1 and S phases.

### Step 4: Conclusion for each phase
- **At G1**: 14 chromosomes
- **After S**: 14 chromosomes
- **After M**: 14 chromosomes

### Final Answer
The number of chromosomes in the diploid cell at G1, after S, and after M phase respectively is:
- **14, 14, 14**