Q.What are restriction enzyme. Mention their type with role in Biotechnology.

Step 1. Define restriction enzymes. A restriction enzyme (restriction endonuclease) is an enzyme that cleaves DNA into fragments at or near specific recognition sites known as restriction sites, first isolated from E. coli in 1963 as part of a bacterial defence system against bacteriophage.

Step 2. Describe the two mechanism-based types. Based on mode of action, restriction enzymes are classified into Exonucleases, which remove nucleotides one at a time from a DNA molecule's end (e.g. Bal 31, Exonuclease III), and Endonucleases, which break internal phosphodiester bonds within the molecule (e.g. Hind II, EcoRI, PvuI, BamHI, TaqI).

Step 3. Describe the three broader classes. There are also three classes by overall mechanism - Type I, Type II and Type III - of which only Type II is used in recombinant DNA technology, because it recognises and cuts within a specific, usually palindromic, 4-8 bp sequence rather than cutting at a variable distance from it. …

Define restriction enzymes, describe their exonuclease/endonuclease and Type I/II/III classifications, and connect Typ …

• Omitting that only Type II restriction enzymes are actually used in recombinant DNA technology. …