Can there be DNA replication without cell division? - Biology

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Answer in Brief

Can there be DNA replication without cell division?

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Solution

Indeed. Endomitosis is the process by which a set of chromosomes in the nucleus multiply without undergoing cytokinesis or karyokinesis, producing several copies in every cell. There are two varieties.

  1. Polyteny: In this case, chromosomes split and re-divide without chromatid separation, resulting in multistranded chromosomes that contain several copies of DNA. These polytene (many stranded) chromosomes, such as the Drosophila polytene (salivary glands) chromosome, have 512–1024 chromatids and do not go through the cell cycle. The quantity of chromosomal sets remains unchanged in this instance.
  2. Polyploidy (endoduplication): Here, the nucleus does not divide; instead, each set of chromosomes divides together with its chromatids. As a result, there are more sets of chromosomes in the nucleus (4x, 8x, etc.). We refer to this expansion in chromosomal sets as polyploidy. Granosan and colchicine have the ability to induce it. These chromosomes travel through the cell cycle and are normal.
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Chapter 10: Cell Cycle and Cell Division - Exercises [Page 172]

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NCERT Biology Class 11
Chapter 10 Cell Cycle and Cell Division
Exercises | Q 15 | Page 172

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