What replicates during mitosis?

During mitosis, the primary structure that replicates is the cell's genetic material, specifically the chromosomes. Before mitosis begins, during the S phase of the cell cycle, each chromosome is replicated to form two identical sister chromatids, which are held together at a region called the centromere.

During mitosis, these sister chromatids are separated and distributed into two daughter cells, ensuring that each new cell receives an identical set of chromosomes. In addition to chromosomes, other cellular components, such as organelles and cytoplasmic contents, are also divided between the two daughter cells, but the specific replication event that occurs during mitosis is the separation of the replicated chromosomes.