Question

In E. coli, the enzyme that fills gaps in duplexes by adding nucleotides to the 3’ end is called:

• A. Type II restriction endonucleases
• B. DNA polymerase I
• C. DNA ligase
• D. Terminal transferase

Hint:

DNA polymerase I = ”gap-filling enzyme” in prokaryotic DNA replication.

Answer 1

The Correct Option is B

DNA polymerase I in E.coli is responsible for filling gaps in the DNA duplex by adding nucleotides to the 3’ hydroxyl group. It has both polymerase and exonuclease activities, enabling it to remove primers and replace them with DNA.