Restriction endonucleases
A) cleave single stranded DNA preferentially.
B) cleave DNA at specific sequences only when those sequences are unmethylated.
C) remove bases one at a time from the 5' end of the DNA only when the bases are incorrectly matched with the template strand.
D) initiate the repair process by making a single endonucleolytic incision at the 5' end of the damaged DNA region.
E) are required for the correct processing of tRNA in the cell.

Question

Quizplus · Accepted Answer

Restriction endonucleases cleave DNA at specific sequences called restriction sites. However, they only cleave these sequences when they are unmethylated. Methylation of the restriction site prevents cleavage by the endonuclease. This is a protective mechanism for the host cell, which methylates its own DNA to prevent cleavage by its own restriction enzymes.

Restriction Endonucleases