Optometry Admission Test (OAT) Practice

What characterizes the M phase of cell division?

1. Organelle doubling

2. DNA synthesis

3. Cell division into two daughter cells

4. Circadian rhythm regulation

The correct answer is: Cell division into two daughter cells

The M phase, also known as the mitotic phase, is specifically characterized by the process of cell division where a single cell divides to form two daughter cells. This phase encompasses the events of mitosis, which involves the separation of duplicated chromosomes and their distribution into each new cell, followed by cytokinesis, where the cell's cytoplasm divides, completing the formation of the two daughter cells. During this phase, a series of tightly regulated steps take place, such as prophase, metaphase, anaphase, and telophase, leading up to cytokinesis. The primary purpose of the M phase is to ensure that each daughter cell receives an identical set of chromosomes, maintaining the genetic integrity of the organism. In contrast, organelle doubling is a feature of the earlier phases of the cell cycle, specifically the S phase, where DNA synthesis also occurs. Circadian rhythm regulation does not play a direct role in the cell division process, as it pertains more to biological rhythms influenced by environmental cycles. Thus, the defining characteristic of the M phase is its role in the actual process of dividing the cell into two distinct daughter cells.