OCR GCSE Biology 2026 – 400 Free Practice Questions to Pass the Exam

The cell cycle is a series of phases that a cell goes through from the time it is formed until it divides into two daughter cells. The correct choice identifies the starting and ending point of the cell cycle as occurring with mitosis, which is the process of cell division.

Mitosis is crucial because it is the phase where the replicated chromosomes are separated and distributed into two new nuclei, resulting in two genetically identical daughter cells. This process ensures that each new cell receives an exact copy of the DNA.

While interphase does play a significant role as the phase in which the cell grows and replicates its DNA in preparation for division, it is not the starting point of the complete cycle nor the point where one cycle ends and another begins. DNA replication occurs within interphase and is part of the events leading up to mitosis, but it is not itself the ending point of the cell cycle. Cellular respiration is unrelated to the cell cycle, as it refers to the biochemical processes through which cells produce energy.

Thus, identifying mitosis as the start and endpoint of the cell cycle reflects an understanding of how cells grow, replicate their materials, and ultimately divide.