Final answer:
DNA polymerase I and DNA ligase participate in DNA replication with distinct roles: DNA polymerase I removes RNA primers and fills in replaced segments with DNA, while DNA ligase joins Okazaki fragments by forming phosphodiester bonds. Incorrect claims such as DNA polymerase I adding primers or DNA ligase separating ends should be corrected, as primase adds primers and ligase joins DNA fragments.
Step-by-step explanation:
Comparison Between DNA Polymerase I and DNA Ligase
In DNA replication, both DNA polymerase I and DNA ligase play crucial roles but perform different functions. DNA polymerase I has a few activities including the ability to add nucleotides and to remove and replace RNA primers with DNA nucleotides, thanks to its exonuclease activity. More specifically, DNA polymerase I uses its 5→3' exonuclease activity to remove the RNA primer at the ends of Okazaki fragments, and fills in the resultant gaps with DNA nucleotides. This is opposed to DNA ligase, which secures the DNA backbone by creating phosphodiester bonds between the Okazaki fragments on the lagging strand, sealing the nicks left after the RNA primers have been replaced with DNA.
It is essential to correct misunderstandings regarding these enzymes. DNA polymerase I does not add RNA primers; that function is performed by primase. DNA ligase does not separate the ends of DNA segments; instead, it joins the DNA fragments together. Furthermore, Okazaki fragments are not found on the leading strand; they are synthesized on the lagging strand in a discontinuous manner.
During replication, proofreading and repair are also significant functions. DNA polymerase I plays a role in this by removing mispaired bases as part of its proofreading ability. Lastly, neither DNA polymerase I nor DNA ligase directly initiates DNA synthesis; initiation is carried out by the combined action of multiple enzymes including helicase and primase.