NEET BIOLOGY

Detailed explanation-1: -Restriction enzymes are found in bacteria (and other prokaryotes). They recognize and bind to specific sequences of DNA, called restriction sites. Each restriction enzyme recognizes just one or a few restriction sites.

Detailed explanation-2: -The natural source of restriction endonucleases are bacterial cells. These enzymes are called restriction enzymes because they restrict infection of bacteria by certain viruses (i.e., bacteriophages), by degrading the viral DNA without affecting the bacterial DNA.

Detailed explanation-3: -These enzymes occur naturally in bacteria as a defense against bacteriophages – viruses that infect bacteria. Bacterial restriction enzymes cut the invading bacteriophage DNA while leaving the bacterial genomic DNA unharmed due to addition of methyl groups.

Detailed explanation-4: -Restriction enzymes, or more formally ‘restriction endonucleases’ (REase), occur naturally in all free-living bacteria and archaea and serve to protect these microbes from infections by viruses and parasitic DNA molecules.