In E. coli, what is the function of DNA polymerase III?
A) to unwind the DNA helix during replication
B) to seal together the broken ends of DNA strands
C) to add nucleotides to the 3' end of a growing DNA strand
D) to degrade damaged DNA molecules
E) to rejoin the two DNA strands (one new and one old) after replication

Question

Quizplus · Accepted Answer

DNA polymerase III is the main polymerase involved in extension of the leading and lagging strands during DNA replication. It adds nucleotides to the 3' end of the growing DNA strand.

Answer: E
 After the leading and lagging strands are synthesized by DNA polymerase III, the two strands must be rejoined to form a circular, double-stranded DNA molecule. This process is called ligation, and it is carried out by enzymes called ligases. However, DNA polymerase III does play a role in repairing DNA damage by replacing missing nucleotides, and it is involved in a range of other DNA metabolic processes as well.

In E Coli, What Is the Function of DNA Polymerase III