Final answer:
In cell division, chromosomes are duplicated during the S phase of interphase and then evenly separated during mitosis. The S phase results in 92 sister chromatids in a human cell, which are then aligned, separated, and distributed into two new nuclei in the subsequent stages of mitosis.
Step-by-step explanation:
During cell division, chromosomes and their structure play a crucial role in ensuring that genetic material is accurately replicated and distributed to the daughter cells. The phases of cell division include interphase, consisting of Gap 1 (G1), DNA synthesis (S phase), and Gap 2 (G2), followed by mitosis and cytokinesis. Throughout interphase, the cell grows and DNA replication occurs, the result of which are sister chromatids connected at a centromere. During mitosis, these chromatids are then separated and distributed to the new cells.
Specifically, in the S phase, each chromosome is duplicated, resulting in two sister chromatids. By the end of this phase, a human cell, which originally has 46 chromosomes, will contain 92 chromatids. When a cell enters mitosis, the chromatids undergo a series of events during which they align at the cell's equator (metaphase), are pulled apart to opposite poles of the cell (anaphase), and finally are enclosed in two new nuclei (telophase). The cell cycle also includes the G2 phase where cells prepare for mitosis, which involves an increase in synthesis of proteins like tubulin and cohesin, critical for the formation and function of the mitotic spindle and chromosome cohesion, respectively.