What is the function of DNA ligase during DNA replication?

What is the function of DNA ligase during DNA replication?

• A. To unwind the DNA double helix
• B. To connect Okazaki fragments on the lagging strand
• C. To synthesize RNA primers
• D. To replace RNA with DNA nucleotides

Answer: (B)

DNA ligase plays a crucial role in DNA replication, particularly on the lagging strand where Okazaki fragments are formed. During replication, the DNA double helix is unwound, creating two strands: the leading strand and the lagging strand. The leading strand can be synthesized continuously, but the lagging strand is synthesized in short segments known as Okazaki fragments due to the antiparallel nature of DNA strands. Since these fragments are initially separated by gaps, DNA ligase is responsible for sealing these gaps by forming covalent bonds between the sugar-phosphate backbones of adjacent Okazaki fragments. This enzymatic action results in a continuous DNA strand that can function effectively in genetic processes. The use of DNA ligase is essential for maintaining the integrity and continuity of the newly synthesized lagging strand during replication. The other options pertain to different functions within DNA replication: unwinding the double helix is primarily the function of helicase, synthesizing RNA primers is done by primase, and replacing RNA with DNA nucleotides is specifically performed by DNA polymerases. This differentiation highlights the specialized roles of each enzyme in the complex process of DNA replication.

DNA ligase plays a crucial role in DNA replication, particularly on the lagging strand where Okazaki fragments are formed. During replication, the DNA double helix is unwound, creating two strands: the leading strand and the lagging strand. The leading strand can be synthesized continuously, but the lagging strand is synthesized in short segments known as Okazaki fragments due to the antiparallel nature of DNA strands.

Since these fragments are initially separated by gaps, DNA ligase is responsible for sealing these gaps by forming covalent bonds between the sugar-phosphate backbones of adjacent Okazaki fragments. This enzymatic action results in a continuous DNA strand that can function effectively in genetic processes. The use of DNA ligase is essential for maintaining the integrity and continuity of the newly synthesized lagging strand during replication.

The other options pertain to different functions within DNA replication: unwinding the double helix is primarily the function of helicase, synthesizing RNA primers is done by primase, and replacing RNA with DNA nucleotides is specifically performed by DNA polymerases. This differentiation highlights the specialized roles of each enzyme in the complex process of DNA replication.