What occurs during the G1 phase of the cell cycle, which is part of interphase preceding mitosis?

• A. Sister chromatids are pulled apart to opposite poles of the cell.
• B. The cell grows and synthesizes proteins necessary for DNA replication.
• C. Chromosomes align at the cell's equatorial plane.
• D. The nuclear envelope breaks down and spindle fibers form.

Answer: (B)

Verified step by step guidance

1. Understand that the cell cycle consists of interphase and mitotic phase. Interphase is further divided into G1, S, and G2 phases.
2. Recognize that the G1 phase is the first stage of interphase, where the cell grows and carries out normal metabolic processes.
3. During the G1 phase, the cell increases in size and synthesizes various proteins and organelles necessary for the subsequent phases of the cell cycle.
4. The synthesis of proteins during the G1 phase is crucial for preparing the cell for DNA replication, which occurs in the S phase.
5. Note that the G1 phase is distinct from mitosis, where processes like chromosome alignment and nuclear envelope breakdown occur.