(a) Mention the difference in the mode of action of exonuclease and endonuclease.
(b) How does restriction endonuclease function?

Explanation

(a) Exo-nuclease cuts nucleotide from the end of DNA while endonuclease cuts DNA at specific positions within DNA.
(b) First restriction endonuclease recognizes and then cuts specific palindromic sequences in the DNA.