What is the function of ligase in DNA replication?

What is the function of ligase in DNA replication?

• A. Unwinds the DNA double helix.
• B. Links or ligates the pieces of DNA together.
• C. Removes RNA primers.
• D. Synthesizes RNA primers.

Answer: (B)

DNA ligase is the enzyme that seals the gaps in the sugar–phosphate backbone to form a continuous DNA strand. During replication, the lagging strand is built in short pieces called Okazaki fragments. After the RNA primers are removed and the fragments are filled in with DNA, ligase joins the fragment ends together by forming phosphodiester bonds, giving a complete, single DNA molecule. Other activities are performed by different enzymes: unwinding of the double helix is done by helicase, removing RNA primers is done by enzymes like RNase H or DNA polymerase I, and synthesizing RNA primers is the job of primase.

DNA ligase is the enzyme that seals the gaps in the sugar–phosphate backbone to form a continuous DNA strand. During replication, the lagging strand is built in short pieces called Okazaki fragments. After the RNA primers are removed and the fragments are filled in with DNA, ligase joins the fragment ends together by forming phosphodiester bonds, giving a complete, single DNA molecule.

Other activities are performed by different enzymes: unwinding of the double helix is done by helicase, removing RNA primers is done by enzymes like RNase H or DNA polymerase I, and synthesizing RNA primers is the job of primase.