A prokaryotic replisome typically contains three molecules of DNA pol III, but only one molecule of DNA pol I. Why?
A) The DNA pol I works on the leading strand, while DNA pol IIIs work on the Okazaki fragments. since there are several of those, it takes more proteins to keep up.
B) DNA pol I has a built-in proofreading exonuclease; DNA pol III does not. The second DNA pol III is needed to follow the first to accomplish the necessary proofreading.
C) The DNA pol IIIs do most of the work. DNA pol I only has to work on the telomers.
D) DNA pol I replaces the RNA primers with DNA, which really only needs to be done repetitively on one strand, while both strands are worked on by the DNA pol IIIs.

Question

Quizplus · Accepted Answer

DNA pol I is responsible for removing RNA primers and replacing them with DNA, a task that occurs on both strands but is more intermittent compared to the continuous DNA synthesis carried out by DNA pol III. DNA pol III is the main enzyme for DNA synthesis, working on both the leading and lagging strands, hence the need for multiple molecules.

A Prokaryotic Replisome Typically Contains Three Molecules of DNA Pol