Abnormal Mitosis of Cell cycle
Cell cycle of Class 11
(i) Intranuclear Mitosis:- (Closed/ Pre-Mitosis) e.g. Amoeba, yeast, Algae (Some of fungi). Nuclear membrane doe’nt degenerate during mitosis. Spindle formed in the nucleus.
(ii) Dinomitosis:- e.g. Dinoflagellalis. Nuclear envelope does’nt degenerate and intranuclear spindle is not formed. They contain condensed chromosome even in non dividing cell.
(iii) Endomitosis (Endoduplication):- Chromosome replicate without subsequent nuclear division. As a result genomes increase and called endopolyploidy. e.g In Boneliver cell(Human).
(iv) Nuclear division:- e.g. Rhizopus, vaucheria, opalina. Repeated mitosis occurs without subsequent cytokinesis produced the coenocyte/ syneytium condition.
- •Colchicine (Alkaloid derived from C. autumnale of liliaceae) interferes with spindle formation.It is infact cell poision which arrest cell division at metaphase and can induce POLYPLOIDY.
