Check sibling questions

How do organisms, whether reproduced asexually or sexually maintain a constant chromosome number through several generations? Explain with the help of suitable example.

 

Answer:

During asexual reproduction, organisms undergo only mitotic cell divisions . The DNA of the cells involved are replicated and then divided evenly among the two daughter cells formed. Thus, the chromosome number remains unchanged.

During sexual reproduction, organisms undergo meiosis ie., the chromosome number is halved to form gametes. Two gametes fuse together to form the zygote and thus the chromosome number is restored.

Example: In humans, each parent has 23 pairs of chromosomes. In the gametes, the sperms have half the number of chromosomes , i.e. 23 and the egg also has 23 chromosomes . When the sperm and the egg fuse , the zygote is formed having 23 pairs or 46 chromosomes. Thus, the chromosome number remains constant.

CHROMOSOMES DIVISION IN SEXUAL REPRODUCTION - Teachoo.png

 

 


Transcript

CHROMOSOMES DIVISION IN SEXUAL REPRODUCTION - IN HUMANS

CA Maninder Singh's photo - Co-founder, Teachoo

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CA Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 12 years and a teacher from the past 16 years. He teaches Science, Economics, Accounting and English at Teachoo