DNA ANALYSIS - KEY

Original Document: DNA Analysis on Recombination

I will include photos of the completed sequences when I get a chance, for now, just including answers to the analysis questions. The plasmid should be circular with a section of human DNA spliced into the circle.

Discussion Questions

1. Why was it important to find an enzyme that would cut the plasmid at only one site? What could happen if the plasmid were cut at more than one site? You simply want to open the circular DNA so that the human DNA can be inserted into the circle. If the enzymes cut at multiple spots, then you would get multiple fragments.

2. Which restriction enzyme did you use? __several are possible__ Ask other groups what they used and compare the final transgenic plasmids. Why might there be some of different lengths? it depends on where the enzyme cut the human DNA, it could have made a longer chunk

3. Why was it important to discard any enzymes that cut the plasmid at the replication site? if you want your DNA to be copied, then you need the bacteria to be able to reproduce, the replication site is necessary

4. Why is it important to cut the plasmid and the human DNA with the same restriction enzyme? the ends need to match so that you can splice them together

5. Do restriction enzymes exist naturally in organisms? If so, what is their purpose? they attack and destroy invaders, such as viruses

6. Why would restriction enzymes that created "blunt" ends not be as useful in recombination as those that create sticky ends? the blunt ends will not stick to other DNA

7. In the activity, you simulated creating a recombinant bacteria organism. For each of the following materials, indicate what they represent?
Scissors ______restriction enzyme____
Tape ______ligase_________