Question

During DNA replication, Okazaki fragments are used to elongate.
A. The lagging strand away from the replication fork.
B. The leading strand towards the replication fork.
C. The lagging strand towards replication fork
D. The leading strand away from the replication fork.

Answer 1

Hint:- DNA is self-replicating and it replicates semi-conservatively. However, a set of enzymes catalyze DNA replication. In the process of DNA replication, DNA makes several copies of itself. It is biological polymerization that continues in initiation, elongation, and termination series. It is a reaction catalyzed by an enzyme. The principal enzyme in the replication cycle is DNA Polymerase.

Complete Answer:-
Following are three important steps involved in DNA replication:
Initiation – There is a specific region in the DNA called the origin of replication where the replication starts. The point from which the replication originates is this. Replication starts with this origin being spotted, accompanied by the unwinding of the two strands of DNA. Due to high energy input, the unzipping of DNA strands across their length is unfeasible. Therefore, a replication fork which is an opening in the DNA strand is formed first, catalyzed by a polymerase enzyme.
The polymerase enzymes begin to synthesize a complementary sequence in each of the strands when the strands are separated. The parental strands can serve as the blueprint for daughter strands that are newly synthesized. It is to be noted that there is unidirectional elongation, i.e. DNA is only polymerized in the 5′ to 3′ direction at all times. Therefore, it is continuous in strand (3 'to 5' template), and in the 5 'to 3' template, it is discontinuous replication. The leading strand is continuously synthesized, while short pieces called Okazaki fragments are synthesized along the lagging strand. As the replication fork further opens, new Okazaki fragments emerge. The direction of elongation will be away from the replication fork, as the first Okazaki fragment appears away from the replication fork.
Termination of replication happens in various ways in different species. Chromosomes are circular in E.coli-like species and this occurs when the two replication forks meet each other between the two terminals.
So, the correct answer is Option (A).

Note:- DNA replication is a highly enzyme-dependent process. DNA replication requires many enzymes, including DNA-dependent DNA polymerase, helicase, ligase, etc. The primary enzyme among them is DNA-dependent DNA polymerase.