Restriction endonucleases

Definition

Restriction endonucleases are enzymes that cut DNA at specific nucleotide sequences known as recognition sites. They are essential tools in molecular biology for gene cloning and DNA analysis.

5 Must Know Facts For Your Next Test

1. Restriction endonucleases recognize and cleave specific sequences of DNA, typically 4-8 base pairs long.
2. They produce either blunt ends or sticky ends, which are overhangs that can be used to join different pieces of DNA together.
3. These enzymes are derived mainly from bacteria and archaea, where they serve as a defense mechanism against viral DNA.
4. There are thousands of known restriction enzymes, each with unique recognition sites and cleavage patterns.
5. They play a crucial role in genetic engineering techniques such as recombinant DNA technology, gene cloning, and genome mapping.

Related terms

Ligase:

An enzyme that facilitates the joining of two large molecules by forming a new chemical bond.

Plasmid:

A small circular piece of DNA found in bacteria that can replicate independently of chromosomal DNA.

Gel Electrophoresis:

A technique used to separate mixtures of DNA, RNA, or proteins according to their size.