Which enzyme is responsible for joining Okazaki fragments by linking different sections of DNA formed during DNA replication?

• A. DNA polymerase
• B. Topoisomerase
• C. Helicase
• D. DNA ligase

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the process of DNA replication. During DNA replication, the DNA double helix is unwound, and new complementary strands are synthesized. The leading strand is synthesized continuously, while the lagging strand is synthesized in short fragments called Okazaki fragments.
2. Step 2: Identify the role of enzymes involved in DNA replication. DNA polymerase synthesizes new DNA strands by adding nucleotides to the growing chain. Helicase unwinds the DNA double helix, and topoisomerase prevents supercoiling during replication.
3. Step 3: Recognize the specific function of DNA ligase. DNA ligase is the enzyme responsible for joining Okazaki fragments on the lagging strand by forming phosphodiester bonds between the fragments, creating a continuous DNA strand.
4. Step 4: Compare the functions of the enzymes listed in the options. DNA polymerase synthesizes DNA but does not join fragments. Topoisomerase prevents supercoiling but does not link DNA sections. Helicase unwinds the DNA but does not join fragments. DNA ligase specifically links Okazaki fragments.
5. Step 5: Conclude that DNA ligase is the correct enzyme responsible for joining Okazaki fragments during DNA replication, as it performs the essential task of linking the fragments into a continuous strand.