Optometry Admission Test (OAT) Practice

Which of the following stages directly involves the final division of the cell?

1. G1 phase

2. S phase

3. G2 phase

4. M phase

The correct answer is: M phase

The M phase, or mitotic phase, is the stage of the cell cycle that directly involves the final division of the cell. During this phase, the processes of mitosis (the division of the nucleus) and cytokinesis (the division of the cytoplasm) occur. Mitosis is further divided into several stages: prophase, metaphase, anaphase, and telophase, which are critical for the accurate segregation of the replicated chromosomes into two daughter cells. Cytokinesis follows mitosis and completes the cell division process by physically separating the two new nuclei and their accompanying cytoplasmic components. In contrast, the G1 phase is primarily focused on cell growth and preparation for DNA synthesis, the S phase is dedicated to the replication of DNA, and the G2 phase involves further growth and preparation for mitosis, including ensuring that all cellular components are ready for division. None of these stages involve the actual division of the cell, which is why they do not serve as the correct answer in this context.