Question

What is DNA replication? Write the chemical composition of DNA.

Answer 1

DNA replication is the basis of biological inheritance in all living beings. The process gives rise to two identical replicas of the original DNA molecule. Replication begins at specific locations in the genome and the unwinding of DNA occurs with the help of the enzyme helicase and gyrase. The new strand synthesis takes place in the 5'-3' direction by the enzyme DNA polymerase. The synthesis of new strands is bidirectional. The two copies of the DNA which are synthesised are equally distributed to the two new cells which are formed after cell division. This process takes place in the S-phase of the interphase. The DNA molecule is a double helix with two strands running in the opposite directions. There are complementary base pairs which are present in the two strands which bind and allow the double helical molecule to be formed. There are four nitrogen bases, adenine (A), thymine (T), cytosine (C) and guanine (G). The nucleotide contains the deoxyribose sugar, phosphate and nitrogen base.