Why are sister chromatids important during cell division?

Sister chromatids are crucial during cell division because they ensure that genetic material is equally divided between the two resulting daughter cells. Each chromosome is duplicated during the S phase of the cell cycle, resulting in two identical copies called sister chromatids that are connected at a region known as the centromere.

During mitosis, specifically in the anaphase stage, the sister chromatids are pulled apart by spindle fibers and moved to opposite ends of the cell. This separation is essential for maintaining the correct number of chromosomes in each daughter cell, thereby preserving the genetic integrity of the cells. If sister chromatids do not separate properly, it can lead to aneuploidy, which is an abnormal number of chromosomes in a cell and can result in various genetic disorders or diseases like cancer.

The other options do not accurately describe the function of sister chromatids; they are not involved in metabolic functions, do not affect cell size directly before division, nor do they determine cell type, which is generally governed by the expression of specific genes rather than the presence of sister chromatids.