BIOL 1011K Unit 10 Biomolecular techniques
Attach the DNA Extraction photo from Part A, step 11.
- Attach photos of the completed EcoRI gel simulations from Part B (include the crime scene DNA analysis as well as all 3 suspects’ results)
- Attach photos of the completed HaeIII gel simulations from Part B (include the crime scene DNA analysis as well as all 3 suspects’ results)
- For what purposes is DNA extraction done? (give at least 3 purposes for which you may need to extract DNA)
DNA extraction can be used for detecting viruses, police investigations, as well as for diagnostic processes.
- Why was it necessary to mash the strawberries extensively with your hands? (hint: you wouldn’t have to do this step with an animal cells)
To break down the cell wall.
- Why do we treat the cells with soap when conducting DNA extraction?
The soap acts as the extraction buffer, helping to release the DNA
- Why do we add salt when doing the DNA extraction?
To dissolve the other, unnecessary components of the cell.
- What is a protease enzyme? Why would we treat the strawberry extract with a protease in an extraction where the DNA needed to be subsequently analyzed?
Proteases are enzymes that break long chain molecules (proteins) into peptides, then those peptides into amino acids.
- In gel electrophoresis, are the DNA fragments attracted to, or repelled from the negative pole of the electric field? The positive pole? Why are these attractions and repulsions important to the process?
DNA has a negative charge so it is attracted to the positive pole (attracted to opposites), it is important to separate the DNA from the other molecules in order to get an accurate read.
- Did both restriction enzymes point to the same suspect as the guilty party in the gel electrophoresis simulation? Which suspect was guilty of the crime according to your analysis?
- Is it easier to exclude a suspect in a criminal case on the basis of DNA evidence, or it is easier to convict a suspect? Why is this the situation?
It is easier to exclude a suspect in a criminal case on the basis of DNA evidence due to the fact that if the DNA markers don’t match then the person is for the most part excluded, but there are a lot of issues that can arise in the collection, the manipulation, and processing of decoding the DNA that it cannot always be 99.99% accurate, and most likely would require multiple samples of DNA to verify that the process was done accurately.
- When analyzing the DNA in a blood sample from the crime scene, why was it important that there were white blood cells in the sample, rather than having only red blood cells?
Red blood cells do not contain DNA, but white blood cells do contain DNA which is why it is important that they are present in the sample collected from a crime scene.
- Which restriction enzyme used in your simulated electrophoresis experiment produced DNA with ‘sticky ends’? Which produced blunt ends? Of these two restriction enzymes, which would you choose to use as donor DNA to graft (or splice) onto a recipient strand of DNA, and why?
- When doing the virtual DNA microarray analysis, which color (red, green or yellow) would the spot be if that gene was inappropriately inactivated in the cancer cell?
- When doing the virtual DNA microarray analysis, which color (red, green or yellow) indicated that the cancer cell had an activated a gene that is not normally as active in the non-cancerous version of the cell?