Question

Enzymes that cut up DNA into characteristic fragments are called: What are the two different types of these enzymes called?

Answer 1

•Restriction enzymes are also called 'molecular scissors' as they cleave DNA at or near specific recognition sequences in the DNA known as restriction sites.

In the laboratory, restriction enzymes are used to cut DNA into smaller fragments. The cuts are always made at specific nucleotide sequences.

Different restriction enzymes recognise and cut different DNA sequences.

•The two types of enzymes are:

Endonucleases

- cleaves the phosphodiester bond present internal in the polynucleotide chain.

Exonuclease

-cleaves the phosphodiester bond from ends. Do not require a free 3' or 5' end for their action.