The enzyme DNA ligase is required continuously during DNA replication because
A) fragments of the leading strand must be joined together.
B) fragments of the lagging strand must be joined together.
C) the parental strands must be joined back together.
D) 3'-deoxynucleoside triphosphates must be converted to 5'-deoxynucleoside triphosphates.
E) the complex of proteins that work together at the replication fork must be prevented from falling apart.

Question

Quizplus · Accepted Answer

DNA ligase is responsible for joining together the fragments of the lagging strand during DNA replication, as it is synthesized in short pieces known as Okazaki fragments. The fragments of the leading strand do not require ligation, as they are synthesized continuously in the same direction as DNA unwinding. Therefore, B is the correct answer.

The Enzyme DNA Ligase Is Required Continuously During DNA Replication