Restriction' in restriction enzyme refers to

Options

A. cleaving of phosphodiester bond in DNA by the enzyme
B. cutting of DNA at specific position only
C. prevention of the multiplication of bacteriophage in bacteria.
D. All of the above.

Explanation

The restriction enzymes are called molecular scissors an d are responsible for cutting DNA. Restriction enzymes belong to a class of enzymes called nucleases.
They are of two types
(i) Exonucleases cut DNA at the ends.
(ii) Endonucleases Make cuts at specific positons within the DNA.
These enzymes are present in bacteria to provide a type of defense mechanism called the restriciton modification system.
This system consit of two c omponents, restriction enzyme and modification enzyme The term restriction refer to the function of these enzyme in restricting the propagation of foreign DNA of bacteriophage in host bacterium, i.e., cutting of DNA, at specific position only.