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Last class. Class policies, etc. VNTRs. PCR. Visualizing DNA. DNA is not colored; Can’t see in solution. Separate pieces based on size. Run mixture through an “ agarose ” gel. Agarose solution is like JellO . Liquid when hot, solid( ish ) when cold - Agarose is NOT edible
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Last class Class policies, etc. VNTRs PCR
Visualizing DNA DNA is not colored; Can’t see in solution. Separate pieces based on size Run mixture through an “agarose” gel Agarose solution is like JellO. Liquid when hot, solid(ish) when cold - Agarose is NOT edible - Agarose tastes really, really bad
Visualizing DNA Agarose gel is porous Small pores in gel allow DNA to pass through Smaller DNA passes easily, larger DNA less easily
Agarose gels - +
Agarose gels http://www.youtube.com/watch?v=2UQIoYhOowM
Important points of agarose gels Why do you need a “buffer?” - - - Why do you add glycerol? - Why do you need the “dye”? -
How to see DNA bands Gel/buffer contains ETHIDIUM BROMIDE (EtBr) EtBr in DNA + UV light = HIGH fluorescence EtBr + UV light = low fluorescence Regions in gel with DNA will show a BRIGHT “band” http://wikidoc.org/index.php/Agarose_gel_electrophoresis
Size markers/DNA ladders See DNA. But size? Run DNA fragments of known length Distance run = size of DNA (compare to ladder) 2000 bp 1000 bp 600 bp 500 bp 400 bp 300 bp 200 bp http://wikidoc.org/index.php/Agarose_gel_electrophoresis
Changing gel running conditions Increase voltage – run quicker… but… Increase percentage of gel - … Increase time of run – run longer …
Lab 2 Gel will be poured for you Load and run gel Check results Lab 3 onwards = pour your own gel
Working with DNA Genes/regions of interest in larger pieces of DNA Isolate gene/region of interest to study it/products Examples of things you can do with DNA: - Clone - Amplify - Mutate First step: Isolate or cut out gene/DNA of interest Need DNA “scissors”!
Restriction Enzymes (REs) Enzyme that cuts DNA Called a “Restriction” enzyme because:
Type II REs Type II REs “cut” inside dsDNA Type II REs cut at specific recognition sites RE site = specific DNA sequence Almost always a palindromic sequence because: No length limits for RE site. Usually 4-8 nucleotides
How do we study life? I think “X” BECAUSE “Y” Design an experiment to PROVE “X” Experiment: Predict outcomes if “X” is TRUE Predict outcomes if “X” is FALSE Do experiment, observe results Results; Therefore “X” is TRUE/FALSE Unexpected results/observations = Discovery!
RE activity can be regulated RE is an enzyme! - Optimal temperature - Optimal salt concentration/composition - Optimal pH - Time of activity RE cutting is random!
Experimental design Form a hypothesis Design an experiment Predictions?
Lab 2 Design experiment to test ONE variable - Time - Buffer - Enzyme concentration Discuss with partner, other groups & TA Generate experimental design Include controls!