LIFE SCIENCE

Detailed explanation-1: -Restriction endonucleases (REs) are bacterial enzymes that cleave double-stranded DNA.

Detailed explanation-2: -Restriction enzymes cut DNA bonds between 3′ OH of one nucleotide and 5′ phosphate of the next one at the specific restriction site. Adding methyl groups to certain bases at the recognition sites on the bacterial DNA blocks the restriction enzyme to bind and protects the bacterial DNA from being cut by themselves.

Detailed explanation-3: -A restriction enzyme is a protein isolated from bacteria that cleaves DNA sequences at sequence-specific sites, producing DNA fragments with a known sequence at each end. The use of restriction enzymes is critical to certain laboratory methods, including recombinant DNA technology and genetic engineering.