Final answer:
During metaphase, sister chromatids align along the metaphase plate, an imaginary plane equidistant from the cell's poles. They are maximally condensed and remain connected by cohesin at their centromeres. The spindle fibers attached to kinetochores are poised to separate them in the subsequent phase.
Step-by-step explanation:
Events During Metaphase of Cell Division
During metaphase, a critical phase of cell division, several important events occur. The sister chromatids, which are duplicated chromosomes, become highly condensed and visibly distinct structures. Each sister chromatid is connected to spindle fibers that extend from opposite centrosomes located at the cell's poles.
The main event is the alignment of these sister chromatids along the metaphase plate, an imaginary plane that is equidistant from the two centrosomes. This precise alignment is crucial for ensuring that when the chromatids are separated in the following phase, anaphase, each new cell will receive an identical set of chromosomes.
Cohesin proteins keep the sister chromatids attached at the centromeres, while the spindle fibers attached to the kinetochores on the centromeres are responsible for their movement and proper alignment.
Sister chromatids reach their maximum condensation during metaphase, which makes them most visible under a microscope. This state of high visibility is essential for the accurate assessment of chromosome alignment and is used by the cell to check for errors before proceeding with cell division.
Following proper alignment along the metaphase plate, the cell is ready to transition to anaphase, where the sister chromatids are pulled apart by the spindle fibers and move towards opposite poles of the cell.