AP BIOLOGY

Detailed explanation-1: -Metaphase. Chromosomes line up at the metaphase plate, under tension from the mitotic spindle. The two sister chromatids of each chromosome are captured by microtubules from opposite spindle poles. In metaphase, the spindle has captured all the chromosomes and lined them up at the middle of the cell, ready to divide.

Detailed explanation-2: -During metaphase, the cell’s chromosomes align themselves in the middle of the cell through a type of cellular “tug of war.” The chromosomes, which have been replicated and remain joined at a central point called the centromere, are called sister chromatids.

Detailed explanation-3: -The chromosomes are held tightly by these forces constantly pushing and pulling on them. Metaphase can occupy a large portion of the total time of mitosis because chromosome alignment at the center of the cell on the metaphase plate acts as a checkpoint for progression into the next phase, anaphase.

Detailed explanation-4: -During most of the cell cycle, interphase, the chromosomes are somewhat less condensed and are not visible as individual objects under the light microscope. However during cell division, mitosis, the chromosomes become highly condensed and are then visible as dark distinct bodies within the nuclei of cells.

Detailed explanation-5: -During metaphase, all the chromosomes are aligned in a plane called the metaphase plate, or the equatorial plane, midway between the two poles of the cell. The sister chromatids are still tightly attached to each other by cohesin proteins.