Restriction enzymes, also called restriction endonucleases, are molecular scissors that cut DNA at specific locations. These enzymes are a vital tool in molecular biology and genetic engineering, used to manipulate DNA sequences for research and medical purposes. Other terms used to refer to restriction enzymes include molecular scissors, DNA cleaving enzymes, and restriction proteins. They are also often classified according to their recognition sequence, such as Type I, Type II, and Type III. Many restriction enzymes are named after the bacteria in which they were originally found, such as EcoRI, HindIII, and BamHI. Regardless of the name or classification, restriction enzymes are a powerful and essential tool in modern genetic research.