Final answer:
Cohesin proteins ensure that the chromatids are right next to each other and prevent them from separating until cell division.
Step-by-step explanation:
In eukaryotic cells, the chromatin, which consists of DNA and proteins, is organized into tightly packed structures called chromosomes. The chromosomes are composed of two identical sister chromatids held together at the centromere by cohesin proteins.
Cohesin proteins ensure that the sister chromatids are right next to each other. These proteins create a physical link between the chromatids, preventing them from separating until it is time for cell division.
For example, during mitosis, when a cell divides, the cohesin proteins break down, allowing the sister chromatids to separate and become individual chromosomes.