CBSE Class 10 Answered

DNA copying mechanism is extremely necessary for reproduction as copying of DNA helps in transfer of information or characters from parents to offspring. It also generates variations during sexual reproduction. This variation leads to evolution. DNA copying is also necessary because DNA (Deoxyribonucleic acid) is the genetic material found in chromosomes, which are present in the nucleus of a cell. DNA determines the body design of an individual. It carries the genetic information and key for the production of every type of cell proteins, which control the function of living organisms. DNA copying also helps in proper survival of the organism by similar copying and variation during DNA copying leads to evolution.

During sexual reproduction, the reproducing cells or germ cells have half the number (amount) of chromosomes and DNA as compared to somatic or body cells or non-reproducing cells. As the offspring receives one DNA copy from each parent, this complex mechanism helps to maintain the amount of DNA constant in an individual. If the DNA had to get doubled during sexual reproduction, then each generation would have double the amount of DNA content as compared to the previous generation. That is why, the amount of DNA does not get doubled during sexual reproduction.