A plant cell has 12 chromosomes at the end of mitosis. How many chromosomes would it have in the `G_(2)` phase of its next cell cycle

Options

A. 6
B. 8
C. 12
D. 24

Answer

To solve the problem, we need to analyze the cell cycle and the behavior of chromosomes during the different phases. Here’s a step-by-step breakdown:

### Step 1: Understand the Cell Cycle
The cell cycle consists of several phases: G1, S, G2, and M (mitosis). The G1 phase is the first gap phase, the S phase is where DNA synthesis occurs, the G2 phase is the second gap phase, and M phase is where mitosis occurs.

**Hint:** Remember that the cell cycle is divided into interphase (G1, S, G2) and mitotic phase (M).

### Step 2: Identify the Chromosome Number at Mitosis
According to the question, the plant cell has 12 chromosomes at the end of mitosis. This means that after mitosis, each daughter cell will also have 12 chromosomes.

**Hint:** Mitosis results in two daughter cells that have the same chromosome number as the parent cell.

### Step 3: Determine the Chromosome Number in G1 Phase
After mitosis, the cell enters the G1 phase. During this phase, the cell grows and prepares for DNA replication. The number of chromosomes remains the same, which is 12.

**Hint:** The chromosome number does not change during the G1 phase; it remains constant.

### Step 4: Understand the S Phase
During the S phase, the DNA is replicated. While the DNA content doubles, the number of chromosomes remains the same. Each chromosome is now made up of two sister chromatids, but they are still counted as one chromosome.

**Hint:** In the S phase, the amount of DNA doubles, but the number of chromosomes remains unchanged.

### Step 5: Determine the Chromosome Number in G2 Phase
After the S phase, the cell enters the G2 phase. At this point, the cell still has 12 chromosomes, but each chromosome consists of two sister chromatids. Therefore, while the DNA content has doubled, the chromosome number remains at 12.

**Hint:** The G2 phase has the same number of chromosomes as the G1 phase, which is 12.

### Conclusion
At the end of the G2 phase, the plant cell will still have 12 chromosomes. Therefore, the answer to the question is:

**Answer: 12 chromosomes.**