Question

Which of the following bacterial DNA polymerases possess 5′ to 3′ exonuclease activity?

-DNA pol I
-DNA pol II
-DNA pol III
-Two of the above
-None of the above

Answer 1

DNA pol I is the bacterial DNA polymerase that possesses 5' to 3' exonuclease activity, which is responsible for removing RNA primers during DNA replication.

Step-by-step explanation:

The question is asking about the 5′ to 3′ exonuclease activity of bacterial DNA polymerases. In bacteria, the three main DNA polymerases are DNA pol I, DNA pol II, and DNA pol III. Of these, DNA pol I has a domain with 5′ to 3′ exonuclease activity that is responsible for removing RNA primers during DNA replication. This domain can be removed by mild protease treatment, which leaves behind the Klenow fragment possessing polymerization and proofreading activity but without the exonuclease activity. DNA pol II and III are primarily enzymes for repair and DNA synthesis, respectively, and do not possess this exonuclease activity.