AP BIOLOGY

Detailed explanation-1: -restriction enzyme, also called restriction endonuclease, a protein produced by bacteria that cleaves DNA at specific sites along the molecule. In the bacterial cell, restriction enzymes cleave foreign DNA, thus eliminating infecting organisms.

Detailed explanation-2: -Restriction endonucleases are bacterial enzymes that cleave duplex DNA at specific target sequences with the production of defined fragments. These enzymes can be purchased from the many manufacturers of biotechnology products.

Detailed explanation-3: -Restriction enzymes are DNA-cutting enzymes.

Detailed explanation-4: -Restriction endonucleases naturally target DNA duplexes. Systematic screening has identified a small minority of these enzymes that can also cleave RNA/DNA heteroduplexes and that may therefore be useful as tools for RNA biochemistry.

Detailed explanation-5: -In general, restriction enzymes cleave double-stranded DNA. Each restriction enzyme recognizes specific DNA sequences, and cleavage can occur within the recognition sequence or some distance away, depending on the enzyme.