Science
(a) What are chromosomes ?
(b) Explain in brief how stability of DNA content of a species is ensured in sexually reproducing organisms ?
Genetics
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Answer
(a) Chromosomes are thread-like structures present in the nucleus, made up of DNA and proteins. They carry genes and hence transmit genetic information from one generation to the next.
(b) In sexually reproducing organisms, meiosis produces haploid gametes with half the number of chromosomes. During fertilisation, the male and female gametes fuse to form a diploid zygote, restoring the original chromosome number. This alternate halving (meiosis) and doubling (fertilisation) ensures that the DNA content of the species remains stable from generation to generation.
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