During cell cycle, two molecules of DNA are present in chromosome during

Options

A. `G_(1)`-phase
B. Beginning of S-phase
C. `G_(2)`phase
D. End of M-phase

Answer

**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 phase has distinct functions related to cell growth and DNA replication.

2. **Focus on the G1 Phase**: In the G1 phase, the cell is preparing for DNA replication. It is involved in metabolic activities and does not contain two molecules of DNA per chromosome, as DNA replication has not yet occurred.

3. **Examine the S Phase**: The S phase is where DNA synthesis or replication occurs. However, at the very beginning of this phase, the cell has not yet completed the replication process, so it does not have two complete DNA molecules per chromosome.

4. **Analyze the G2 Phase**: The G2 phase follows the S phase. By this point, DNA replication has been completed, and each chromosome consists of two identical sister chromatids. Therefore, during the G2 phase, there are indeed two molecules of DNA present in each chromosome.

5. **Conclusion**: Based on the analysis of each phase, the correct answer to the question is that during the G2 phase, two molecules of DNA are present in the chromosome.

**Final Answer**: During the cell cycle, two molecules of DNA are present in the chromosome during the G2 phase.

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