Final answer:
During early anaphase, cohesin cleavage occurs, leading to the separation of sister chromatids. Cohesin proteins degrade allowing chromatids, now chromosomes, to be pulled to opposite poles, which is essential for cell division.
Step-by-step explanation:
The correct answer to the question of what would you expect to occur during early anaphase is a. Cohesin cleavage. During Anaphase of mitosis, the cohesin proteins degrade, allowing the sister chromatids to separate at the centromere. These separated sister chromatids, now individual chromosomes, are then pulled toward the centrosomes to which their microtubules are attached.
The breakdown of cohesin proteins is a critical step leading to the separation of sister chromatids. This event is facilitated by an enzyme called separase, which cleaves the cohesin proteins allowing the chromatids to be pulled apart. It's important to note that this process happens after the chromosomes have lined up at the metaphase plate and the kinetochore have become attached to the mitotic spindle.
To clarify the steps of mitosis and address related topics: DNA replication occurs during the S phase, prior to mitosis; the nuclear envelope breaks down at the start of mitosis to allow spindle fibers to attach to chromosomes; the fibers made of microtubules that attach to the centromeres are called kinetochore microtubules; and during anaphase, it is False that chromosomes begin to uncoil. Uncoiling of chromosomes occurs later during telophase.