Question: 1. what is the difference between an endonuclease and an exonuclease?
Answer: An endonuclease is a group of enzymes that cleave the phosphodiester bond present within a polynucleotide chain. Exonucleases are enzymes that cleave DNA sequences in a polynucleotide chain from either the 5' or 3' end one at a time. Endonucleases cleave the nucleotide sequence from the middle.