Mitosis results in producing two cells which are similar to each other. What would be the consequence if each of the following irregularities occur during mitosis?
(a) Nuclear membrane fails to disintegrate
(b) Duplication of DNA does not occur
(c) Centromeres do not divide
(d) Cytokinesis does not occur.
Ans.
(a) The spindle fibres would not be able to reach chromosomes if the nuclear membrane fails to disintegrate. Because of this, the chromosomes would not be able to reach the opposite poles of the cell.
(b) The cell may not be able to reach the M phase if the DNA duplication does not take place. This shall result in the cessation of the cell cycle.
(c) If the division of centromeres does not take place, then one of the daughter cells will get a complete pair of chromosomes, and another daughter cell will get none. This may result in trisomy.
(d) If cytokinesis does not occur, then a cell with the multinucleate condition would be formed.