Which statement about DNA polymerase I is true?

Which statement about DNA polymerase I is true?

• A. It functions only replication.
• B. It functions only in RNA synthesis.
• C. It participates in DNA repair and primer replacement during replication.
• D. It ligates Okazaki fragments.

Answer: (C)

DNA polymerase I has several activities that link replication with repair. On the lagging strand, it uses its 5' to 3' exonuclease to remove RNA primers and then its 5' to 3' polymerase activity to fill the resulting gaps with DNA. This primer removal and replacement is a key part of Okazaki fragment processing during replication. Beyond replication, Pol I also participates in DNA repair, helping to excise damaged nucleotides and patch small gaps. Because of these roles, the statement that it participates in DNA repair and primer replacement during replication is true. It is not limited to replication, since repair is part of its function; it does not synthesize RNA (that’s primase), and it does not seal nicks between fragments (that’s the job of DNA ligase).

DNA polymerase I has several activities that link replication with repair. On the lagging strand, it uses its 5' to 3' exonuclease to remove RNA primers and then its 5' to 3' polymerase activity to fill the resulting gaps with DNA. This primer removal and replacement is a key part of Okazaki fragment processing during replication. Beyond replication, Pol I also participates in DNA repair, helping to excise damaged nucleotides and patch small gaps. Because of these roles, the statement that it participates in DNA repair and primer replacement during replication is true. It is not limited to replication, since repair is part of its function; it does not synthesize RNA (that’s primase), and it does not seal nicks between fragments (that’s the job of DNA ligase).