Which is the role of restriction enzymes?

Restriction enzymes and or restriction endonucleases are involved at recognizing specific sequence of nucleotides and cutting or splicing them at appropriate regions to produce fragments that can either be sticky ends or blunt ends depending on where they cut and the nature of nucleotides involved within the fragments. They play an important role in genetic engineering, as geneticists can use them for placing into extra chromosomal information and or content of plasmids in certain bacteria, from other sources, for instance antibiotics, grow and or produce many individual colonies of bacteria, isolate them and one would have many sequences for instance that can code for an antibiotic that can be extracted and used further. Assuming the bacteria's plasmid can take in that sequence.

Try and make the question more clear : )