Question

Discuss briefly,
A. Cells know whether sister kinetochores are properly attached to the mitotic spindle.
B. The Spindle assembly checkpoint pathway prevents chromosome segregation until chromosomes are accurately attached to the mitotic spindle

Answer 1

A) Yes, we could say the cell "knows" that, through an specific chekpoint mechanism that prevents the chromatides from being separated until de spindle achieves to attach to each chromatide, it is called Spindle checkpoint. The whole point of this checkpoint is to avoid the production of aneuploidies due to fail in segregation.

B) Correct, the spindle checkpoint exists to make sure the each sister chromatide attaches correctly to the spindle. If sister chromatides were to deattaches one to another before the spindle is attached, segregation won't occur correctly and sister chromatides might go into a same daughter cell, causing a trisomy in one cell and lack of chromosomes in the other, this is aneuploidy and animal cells die or develop serious conditions when that occurs.