Question

Which enzyme has both 5'-> 3' exonuclease and polymerization activity and is responsible for removing RNA primers from both the leading and lagging strand?

Answer 1

DNA polymerase I is the enzyme with both 5'-> 3' exonuclease activity for primer removal and polymerization activity for DNA synthesis, playing a vital role in removing RNA primers from the leading and lagging strands during DNA replication.

Step-by-step explanation:

The Enzyme with Dual Functions in DNA Replication

The enzyme responsible for removing RNA primers from both the leading and lagging strands and has both 5'-> 3' exonuclease and polymerization activity is DNA polymerase I. This enzyme uniquely performs the crucial task of exonuclease activity, which involves the removal of RNA primers and replacing them with the appropriate deoxynucleotides. During the replication process, DNA polymerase I fills in the gaps left after RNA primers are excised. This process happens sequentially along the Okazaki fragments on the lagging strand, ultimately leading to continuous DNA strand synthesis.

While DNA polymerase I carries out exonuclease activity, flap endonuclease 1 (FEN 1) also aids in the removal of 'flaps' or overhangs during the replication process. Finally, DNA ligase assists in sealing the gaps between Okazaki fragments by forming phosphodiester linkages, creating a continuous strand of DNA.