Second check point of cell cycle lies between

Options

A. `G_1and S` phase
B. `S and S_2` Phase
C. `G_2 and M` phase
D. `M and G_1` Phase

Answer

To determine the second checkpoint of the cell cycle, we need to analyze the phases of the cell cycle and the checkpoints associated with them.

### Step-by-Step Solution:

1. **Understanding the Cell Cycle Phases**:
- The cell cycle consists of several phases: G1 (Gap 1), S (Synthesis), G2 (Gap 2), and M (Mitosis).
- Each of these phases has specific functions and checkpoints to ensure the cell is ready to proceed to the next phase.

2. **Identifying the Checkpoints**:
- The first checkpoint (G1 checkpoint) occurs at the transition between G1 and S phase. This checkpoint assesses whether the cell is ready for DNA synthesis.
- The second checkpoint (G2 checkpoint) occurs between the G2 phase and M phase. This checkpoint checks for DNA damage and ensures that DNA replication has been completed successfully before the cell enters mitosis.

3. **Evaluating the Options**:
- **Option 1**: G1 and S phase - This is incorrect as it refers to the first checkpoint.
- **Option 2**: S and S2 phase - This is incorrect as there is no S2 phase in the cell cycle.
- **Option 3**: G2 and M phase - This is correct as it represents the second checkpoint of the cell cycle.
- **Option 4**: M phase and G1 phase - This is incorrect as it does not represent a valid checkpoint.

4. **Conclusion**:
- The second checkpoint of the cell cycle lies between the G2 phase and the M phase.

### Final Answer:
The second checkpoint of the cell cycle lies between the G2 phase and the M phase.

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