What are the characteristics of DNA polymerase 1, 2 and 3?

DNA polymerase I functions to assist in DNA replication and repair as it fills in gaps left when RNA primers are removed from the DNA during replication. This polymerase exhibits 5′ to 3′ exonuclease activity, which means Pol I can cut out RNA primers from the DNA strand. It helps fix damaged or defective DNA bases through a process called base excision repair (BER). Additionally, DNA polymerase I doesn’t stay attached to the DNA template very long, which makes it less efficient at replicating long DNA strands compared to other polymerases. 

DNA Polymerase II is another enzyme in bacteria that also aids in DNA replication and repair. This polymerase can correct mistakes made during DNA synthesis, improving its accuracy. It plays a key role in repairing DNA damaged by UV radiation and other mutagens through error-prone repair pathways. 

DNA Polymerase III is the main enzyme for DNA replication in bacteria. It is the most critical enzyme for copying DNA during cell division. It is very efficient and can replicate long DNA strands quickly due to its sliding clamp mechanism, which helps it stay attached to the DNA template. It ensures high accuracy in DNA replication with its proofreading ability and corrects errors during DNA synthesis through its 3′ to 5′ exonuclease activity.