Which of the enzymes removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments? Use the list of choices below for the following question: I. helicase II. DNA polymerase III III. ligase IV. DNA polymerase I V. primase Which of the enzymes removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments? I II III IV V

DNA polymerase I has 3' to 5' and 5' to 3' exonuclease activities. The 3' to 5' exonuclease activity is the proofreading activity while the 5' to 3' exonuclease activity of the enzyme is required for the removal of primer and gap-filling during DNA replication. The 5' to 3' exonuclease activity of DNA polymerase I can replace a segment of DNA or RNA paired to the template strand. This removal of the DNA or RNA segment is called nick translation.

Completion of formation of an Okazaki fragment is followed by removal of RNA primer through 5' to 3' exonuclease activity of DNA polymerase I. The same enzyme adds deoxyribonucleotides in the gap by its polymerization activity. The remaining nick is sealed by DNA ligase.