Animation - Restriction Endonucleases

What is the cellular function of restriction endonucleases? The animation below tells you that restriction endonucleases are very useful to molecular biologists. They cut DNA at specific locations and can be used to look for genetic diversity, to cut up DNA into smaller pieces, and/or to splice DNA from different sources into one molecule. In cells restriction endonucleases are used to cut up invading DNA from viruses. The restriction sites are ones found in viral DNA. If, when a virus injects DNA in a bacterium, the restriction enzymes cut up the viral DNA then it cannot take over the bacterium and cause it to manufacture more viruses. Restriction endonucleases are a form of protection against viral infections.

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