AP BIOLOGY

Detailed explanation-1: -Restriction enzymes cut DNA at specific sequences that are found in viral DNA but not bacterial DNA. This destroys the genetic material of invading viruses, protecting the bacterial cell from infections.

Detailed explanation-2: -Restriction enzymes are found in bacteria. Bacteria use restriction enzymes to kill viruses – the enzymes attack the viral DNA and break it into useless fragments.

Detailed explanation-3: -Restriction enzyme function in the natural world is to defend bacteria against specific viruses called bacteriophages. These viruses attack bacteria by injecting viral RNA or DNA into a bacterial plasmid (small, purple ring in the below image) and replicating there.

Detailed explanation-4: -Restriction endonucleases which cleave DNA at specific nucleotide sequences can be used to produce a set of DNA fragments of a viral genome which, when separated by gel electrophoresis, gives a characteristic “fingerprint” for that virus genome.

Detailed explanation-5: -Restriction enzymes are a group of proteins that bacteria produce to cut up the DNA of invading viruses. Electron micrograph of Escherichia coli, close-up. Such bacteria are an important source for restriction enzymes.