Question

Choose the correct answer from the alternatives given:
Discontinuous synthesis of DNA occurs in one strand, because
A.DNA molecule being synthesized is very long
B.DNA dependent DNA polymerase catalyses polymerization only in one direction (5’to 3’)
C.It is a more efficient process
D.DNA ligase has to have a role

Answer 1

DNA replication is a biological process in which two identical copies of parent DNA molecules are synthesized by the enzyme DNA polymerase. It occurs in all the living organisms as the essential part of inheritance.

Complete answer:
During the process of replication the double stranded helix of DNA gets separated. Each strand of FNA now serves as a template for the synthesis of daughter strands. DNA polymerase keeps adding the nucleotides at the growing end of the chain.
Let us analyze the options to find out the correct option.

Option A: DNA molecule being synthesized is very long but this does not affect the efficacy of the replication process in either of the strands being synthesized. Therefore, this is the incorrect option.

Option B: DNA dependent DNA polymerase catalyses polymerization only in one direction (5’ to 3’) this leads to the formation of Okazaki fragments or synthesis in breaks when DNA polymerase synthesizes the discontinuous strand. Therefore, this is the correct option.

Option C: Synthesis of both the strands of DNA is equally efficient. Therefore, this is the incorrect option.

Option D: DNA ligase plays a vital role in joining the breaks in the discontinuous strand of the DNA. These fragments which are called Okazaki fragments are joined by the enzyme DNA ligase. Therefore, this is the incorrect option.

Hence, the correct answer is option (B)

Note: The discontinuous strand is also called the lagging strand of the DNA. In this the primer keeps on assigning itself to form the strand of DNA which are ligated to each other by the enzyme DNA ligase.