Ans.
The replicating molecule in all living organisms is DNA (deoxyribonucleic acid). Each parent DNA molecule replicates to form two daughter DNA molecules at the time of cell division and passes genetic information form one generation to another.
The DNA is polymer of nucleosides, each made up of a 5-carbon sugar, a phosphate molecule and a cyclic nitrogen base. Two DNA strands are bound together with each other with the help of hydrogen bonds between nitrogenous bases (adenine, cytosine, thymine, guanine). The diagram of DNA is given below: