Question

How can discontinuous synthesis of the lagging strand keep up with continuous synthesis of the leading strand?

A) Lagging strand synthesis is faster; leading strand synthesis is slower.
B) Okazaki fragments are shorter; primase synthesizes longer RNA primers.
C) DNA ligase joins Okazaki fragments; DNA polymerase III synthesizes continuously.
D) Lagging strand synthesis is more efficient; leading strand synthesis is error-prone.

Answer 1

DNA replication on the lagging strand keeps up with the leading strand by synthesizing Okazaki fragments simultaneously, which are later joined by DNA ligase to form a continuous strand. The correct option is C.

Step-by-step explanation:

The process of DNA replication on the leading strand and the lagging strand is coordinated to ensure that both are synthesized simultaneously, despite the fact that they are built in different ways. On the leading strand, DNA is synthesized continuously.

In contrast, the lagging strand is synthesized discontinuously in the form of Okazaki fragments, which are later joined together. This is possible because multiple fragments can be synthesized at the same time on the lagging strand.

Each Okazaki fragment begins with an RNA primer made by primase, which is extended by DNA polymerase III. The RNA primers are then replaced with DNA, and DNA ligase joins these fragments to form a continuous strand.

While DNA polymerase III synthesizes continuously on the leading strand, it synthesizes the lagging strand in pieces, albeit rapidly, ensuring no lag behind the continuous synthesis.