AP BIOLOGY

Detailed explanation-1: -During mitosis, chromosomes are attached by their kinetochores to the microtubules of the spindle. In an ‘amphitelic’ attachment, the kinetochore (k)-fibre bundles of microtubules attach each sister kinetochore to opposite spindle poles (see part a in the figure).

Detailed explanation-2: -The spindle is a structure made of microtubules, strong fibers that are part of the cell’s “skeleton.” Its job is to organize the chromosomes and move them around during mitosis. The spindle grows between the centrosomes as they move apart.

Detailed explanation-3: -Kinetochore microtubules attach end-on to the kinetochore, which forms at the centromere of each duplicated chromosome. They serve to attach the chromosomes to the spindle. Overlap microtubules interdigitate at the equator of the spindle and are responsible for the symmetrical, bipolar shape of the spindle.

Detailed explanation-4: -The structure involved in the formation of spindle fibres are centrioles.

Detailed explanation-5: -A structure known as the centrosome duplicates itself to form two daughter centrosomes that migrate to opposite ends of the cell. The centrosomes organise the production of microtubules that form the spindle fibres that constitute the mitotic spindle. The chromosomes condense into compact structures.