University of Central Florida (UCF) PCB3023 Molecular Cell Biology Practice Exam 4

The M phase of the cell cycle is specifically comprised of mitosis and cytokinesis. Mitosis is the process where the cell's chromosomes are duplicated and separated into two separate nuclei, which is critical for ensuring that each daughter cell receives an accurate set of genetic material. Following mitosis, cytokinesis occurs, which is the physical division of the cytoplasm and the cell membrane, leading to the formation of two distinct daughter cells. Together, these two processes ensure that cell division is completed successfully, allowing for the propagation of the organism's cells.

The other choices do not accurately capture the definition of the M phase. Interphase, for instance, includes the stages G1, S, and G2, but does not include the processes of cell division. G0 refers to a quiescent state where cells are not actively dividing, which also does not pertain to the M phase. The S phase is part of interphase where DNA replication occurs, and metaphase is a specific stage within mitosis rather than a separate process. Thus, the understanding of the M phase being defined by both mitosis and cytokinesis emphasizes the full cycle of cell division.