AP BIOLOGY

Detailed explanation-1: -The spindle checkpoint ensures the fidelity of chromosome transmission by delaying anaphase until all chromatid pairs have formed proper links to the mitotic spindle. Sister chromatids attach to spindle microtubules (MTs) via kinetochores, which are multiprotein complexes that assemble on centromeric (CEN) DNA.

Detailed explanation-2: -The spindle assembly checkpoint (SAC) is a surveillance mechanism that promotes accurate chromosome segregation in mitosis. The checkpoint senses the attachment state of kinetochores, the proteinaceous structures that assemble onto chromosomes in mitosis in order to mediate their interaction with spindle microtubules.

Detailed explanation-3: -The M checkpoint determines whether all the sister chromatids are correctly attached to the spindle microtubules before the cell enters the irreversible anaphase stage.

Detailed explanation-4: -M checkpoint – nuclear division setup check It is also called the spindle checkpoint because the cell examines whether all sister chromatids are correctly attached to the spindle microtubules that separate them. If not, the cell pauses mitosis until all sister chromatids have been attached in the right way.

Detailed explanation-5: -To ensure faithful segregation of chromosomes, the spindle checkpoint prevents the metaphase to anaphase transition until all chromosomes experience the tension of the mitotic spindle (Lew and Burke, 2003). Multiprotein kinetochores couple centromeric DNA of chromosomes to microtubules of the mitotic spindle.