Question

Which type of restriction endonucleases recognize specific sites within DNA but do not cut these sites.

• A. $RE-I
• B. $RE-II
• C. $RE-III$
• D. Both 'a' and (b)

Answer 1

The correct option is A $RE-I

• Both type I and type III enzymes recognise specific sequences but do not cut the DNA at the recognition sequences. Instead the type I restriction endonuclease cuts the DNA at sites that are remote (far away) from the recognition sequence and the type III restriction endonuclease cuts the DNA at sequences that are a short distance from the recognition sequence.
• The type II restriction endonuclease recognises and cleaves the DNA at the recognition sequences.

So, the correct option is 'Both (a) and (c)'.