Question
Restriction enzymes:
are endonucleases which cleave DNA at specific sites
make DNA complementary to an existing DNA or RNA
cut or join DNA fragments
are required in vectorless direct gene transfer.
Solution
A.
are endonucleases which cleave DNA at specific sites
Restriction enzymes are endonucleases which cleave DNA at specific sites. They are extracted from the bacterium E.coli.
Restriction enzymes Type I bind to a recognition site of a duplex DNA and cleave one strand only. Restriction Enzyme Type II are more valuable in gene manipulation and cleave the duplex at specific target sites at or near the binding site.
