Final answer:
During interphase, chromosomes are duplicated, resulting in sister chromatids that are later separated during mitosis. This phase is crucial for preparing the cell for division.
Step-by-step explanation:
During interphase, a critical phase of the cell cycle, the chromosomes are duplicated in preparation for cell division. This phase consists of the G1 phase (cell growth), S phase (synthesis of DNA), and G2 phase (preparation for mitosis). In the S phase, each chromosome is replicated to form two identical copies called sister chromatids, which are held together at the centromere. Along with chromosome duplication, the cell's centrosomes are also duplicated during interphase. This sets the stage for the subsequent stages of mitosis where the sister chromatids will be separated and distributed to the daughter cells.