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Biotechniques. Restriction Enzymes endonucleases Bacteria have endonucleases to cut up viral DNA. 400 About 400 different endonucleases Each endonuclease.

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Presentation on theme: "Biotechniques. Restriction Enzymes endonucleases Bacteria have endonucleases to cut up viral DNA. 400 About 400 different endonucleases Each endonuclease."— Presentation transcript:

1 Biotechniques

2 Restriction Enzymes endonucleases Bacteria have endonucleases to cut up viral DNA. 400 About 400 different endonucleases Each endonuclease recognises a specific sequence of about 4-6 nucleotide bases Cut DNA into fragments at these recognition sites

3 Specific different enzymes cut the DNA at different places same enzymes always cut the DNA at the same places enzymes are named after the bacteria they are taken from

4 Protection against cutting Bacteria can protect their own DNA from restriction enzymes add methyl groups to A and C bases in sequences recognised by their own endonucleases

5 Genetic Engineer Toolkits Recognition Sites cuts isolate specific DNA fragments manipulate individual genes from any organism.

6 C T T A A A A T T CG G Sticky Ends Fragment Restriction enzyme: EcoRI C T T A A A A T T C G G C T T A A G G A A T T CG G Cut DNA with an overhang Only complementary sticky ends can join (same restriction enzyme)

7 C C C G G G C C C G G G C C C G G G C C C Blunt Ends can join to any other blunt end fragment - non-specific cut C C C G G G C C C G G G C C C G G G C C C DNA

8 Restriction enzymes http://videos.howstuffworks.com/hsw/22635-discoveries-with-bill- nye-restriction-enzymes-video.htm (restriction enzymes, 1 min) http://videos.howstuffworks.com/hsw/22635-discoveries-with-bill- nye-restriction-enzymes-video.htm http://www.dnatube.com/video/1008/Tissue-Culture (restriction enzymes, 1 min) http://www.dnatube.com/video/1008/Tissue-Culture http://www.youtube.com/watch?v=aA5fyWJh5S0 (restriction enzymes, 1 min – no sound) http://www.youtube.com/watch?v=aA5fyWJh5S0 http://www.youtube.com/watch?v=AEINuCL-5wc&feature=related (restriction enzyme, 3 min – very simple) http://www.youtube.com/watch?v=AEINuCL-5wc&feature=related http://www.youtube.com/watch?v=zF3REf7yKpw&feature=related (restriction enzymes, 7 min – students in lab, no sound??) http://www.youtube.com/watch?v=zF3REf7yKpw&feature=related


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