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Mitosis results in producing two cells w...

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

Text Solution

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(a) If nuclear membrane does not integrate then spindle fibres reach till chromosomes and they can not move towards opposite pole. In some protozoans spindle fibres are made in nucleus only. It is called inter nuclear mitosis.
(b) If DNA replication does not take place then cell can not go further. Then S-phases formation of chromosomes does not take place and can not enter into M-phase.
(c) If centromere does not divide then one daughter cell from two gets complete set of chromosomes. Other cell lacks it due to this trisomy can be seen.
(d) If cytoplasmic division occurs then multinucleate state means coenocytes can be seen and syncytium can be formed eg.Rhizopus and Vaucheria.
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