Question
Wed March 06, 2013 By:

how does cell division takes place in sexual reproduction?

Expert Reply
Fri March 08, 2013

The creation of two new cells from one involves copying of the DNA as well as of the cellular apparatus. The sexual mode of reproduction involves a process of combining DNA from two different individuals during reproduction. Many multi-cellular organisms have special lineages of cells in specialised organs which have only half the number of chromosomes and half the amount of DNA as compared to the non-reproductive body cells. Thus, when these germ-cells from two individuals combine during sexual reproduction to form a new individual, it results in re-establishment of the number of chromosomes and the DNA content in the new generation.

 

Meiosis is a special type of cell division that occurs in sexually reproducing organisms. Meiosis reduces the chromosome number by half, enabling sexual recombination to occur. Meiosis of diploid cells produces haploid daughter cells, which may function as gametes. Gametes undergo fertilization, restoring the diploid number of chromosomes in the zygote. Meiosis and fertilization introduce genetic variation.
The stages of meiosis can be broken down into two main stages, Meiosis I and Meiosis II
  • Meiosis I can be broken down into four substages: Prophase I, Metaphase I, Anaphase I and Telophase I
  • Meiosis II can be broken down into four substages: Prophase II, Metaphase II, Anaphase II and Telophase II
All cell organelles (such as mitochondria, ribosome, chloroplasts, golgi bodies etc.) present inside each cell is called cellular apparatus.
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