Duplication of DNA occurs in a phase which is also associated with synthesis of

Options

A. RNA
B. Histone
C. Cyclins
D. ATP

Answer

**Step-by-Step Solution:**

1. **Understanding the Cell Cycle:**
- The cell cycle consists of two main phases: Interphase and Mitotic phase (M phase).
- Interphase is further divided into three sub-phases: G1 phase, S phase, and G2 phase.

2. **Identifying the Phase of DNA Duplication:**
- DNA duplication occurs specifically during the S phase (Synthesis phase) of Interphase. This is the phase where the cell synthesizes a complete copy of the DNA in its nucleus.

3. **Analyzing the Options:**
- The question asks for a substance that is synthesized during the same phase as DNA duplication (S phase). The options provided are:
- RNA
- Histones
- Cyclins
- ATP

4. **Evaluating Each Option:**
- **RNA:** While RNA is synthesized during the cell cycle, it is not exclusive to the S phase. It can also be synthesized in G1 and G2 phases, making this option incorrect.
- **Histones:** Histones are proteins that package and condense DNA into chromatin. Their synthesis occurs during the S phase alongside DNA replication, making this option correct.
- **Cyclins:** Cyclins are proteins that regulate the cell cycle but are not specifically synthesized during the S phase. Therefore, this option is incorrect.
- **ATP:** ATP is primarily synthesized in the G1 phase to provide energy for various cellular processes, including DNA replication, but it is not synthesized during the S phase itself.

5. **Conclusion:**
- The correct answer is **Histones**, as they are synthesized during the S phase along with the duplication of DNA.

**Final Answer: Histones**

---