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Name the process in which there is an exchange of genetic material between non-sister chromatids of homologous chromsomes during meiosis.


Crossing over.
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“A well known biologist stated that the life history of an organism can be summed up as gametic fusion, equational division and reductional division.” Comment.

The given statement is correct on the basis of the following facts :

1. The gametic fusion takes place at the time of fertilisation when sperm and ovum fuse to form a diploid zygote.

2. The zygote is divided by mitotic division during its embroynic life and post embryonic life to form a well developed individual.

3. A mature individual produces gametes by gametogensis. Reductional division takes place at this stage and results in the formation of haploid gametes.

 

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Draw diagram of mitosis.

. Draw diagram of mitosis.

Mitosis in Animal Cell

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Why is meiosis called the reductional division and mitosis called equational division?

Meiosis is called reductional division because number of chromosomes and amount of DNA in daughter cells is reduced to half than that of parent cell. In meiosis diploid number of chromosomes is reduced to haploid number.

Example. If a parent cell has 16 chromosomes then in daughter cells due to meiotic division number of chromosomes is reduced to eight.

Mitosis. It is called equational division because number of chromosomes and amount of DNA in daughter cells remain equal to parent cells.

Example. If a parent cell has 18 chromosomes, then in daughter cells formed by mitosis have each 18 chromosomes. 

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Draw the diagram of meiosis.


Draw the diagram of meiosis.
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