Restriction Endonuclease: Enzyme that can cleave DNA at a specific base-pair sequence of nucleotides.

Cleaving
1. Sticky Ends: Short single-stranded overhang ends from cleavage. Ready to be paired with new DNA strands.
  1. Restriction Enzyme cuts specific DNA sequence and is added to another DNA gene in a plasmid. The plasmid can then be injected into a bacterial cell and reproduce more genes, known as “recombinant DNA.”
2. Blunt Ends: Fully based paired ends from cleavage. Not ready to bind with new DNA strands.
Types
1. Type I: Cuts random sequences
2. Type II: Cuts specific areas close to or within recognition sequence - most commonly used
3. Type IIS: Cleaves outside recognition sequence to one side. Used on DNA with multiple recognition sites.
4. Type IIG: Cleaves outside recognition sequence and can switch between cleaving other DNA and protecting (methylase) own DNA
5. Type III: Cleaves outside recognition sequence and can switch between cleaving other DNA and protecting (methylase) own DNA
6. Type IV: Recognizes and cleaves modified DNA
Applications
1. Genetic Engineering: Molecular Biologists target sequences then isolate and cleave them. The cleaved strand is then used to modify something else
2. Restriction Fragment Lenth Polymophism (RFLP): Molecular biologists study the fragment length differences in individuals or groups of individuals
3. DNA fingerprinting
4. Immune Systems: When bacteriophage (virus) injects DNA into bacterial cell, the restriction enzyme breaks foreign DNA into segments and renders it useless.

Resource summary

	Created by brittneynmurray about 10 years ago