1. 1/28/2015 SWBAT explain how restriction enzymes can be used to solve a murder mystery.
Bellwork: What are restriction enzymes? (Hint: Think back to the Ch 20 reading guide.)

2. Gel Electrophoresis
SWBAT identify the properties of DNA that allow for data analysis by gel electrophoresis.

3. MURDER!
Mrs. Lewis was found dead in her apartment with multiple stab wounds, but the weapon was nowhere to be found.

4. MURDER!
The only evidence was a pair of glasses that had different lipstick stains on them. One of them has been matched with Mrs. Lewis. The other belongs to the killer.

5. The Suspects
Mrs. Lewis is a busy woman who doesn’t make much time for her friends. Witnesses say that Mrs. Lewis was with a woman, but they didn’t remember what she looked like. Her secretary was able to offer three names of suspects.

6. The Suspects
Regina Carnes
Lauren Gastellum
Alicia Alvarez

7. “Using electricity to move stuff through gel”
Gel Electrophoresis
Electro- -phoresis
To move stuff through
Using Electricity
Gel Electrophoresis:
“Using electricity to move stuff through gel”

8. Gel Electrophoresis Gel – is like Jello
When it is hot it is liquid, but when it is cool it is a solid
Although it solidifies, it is web-like
Fibers criss-cross
Matrix-like: things can pass through the matrix

9. Gel Electrophoresis
Restriction Enzymes cuts DNA into fragments where the sequence matches exactly.
Fragment length will vary.

10. Gel Electrophoresis
DNA fragments are placed at one end of a porous gel, and an electric voltage is applied to the gel.
When turned on DNA molecules will travel through the gel

11. Gel Electrophoresis Restriction Enzymes cut DNA into fragments
These vary in length – some short and some long.
Which size will travel further through the gel?

12. Gel Electrophoresis
Shorter fragments will have a larger distance traveled.

13. Gel Electrophoresis
How does the DNA travel through the gel?

14. The Structure of DNA (review)
Deoxyribonucleic Acid
Nitrogenous Bases
A, T, C, G
Sugar Phosphate “Backbone”

15. The Structure of DNA
The sugar-phosphate “backbone” is NEGATIVELY charged.
Why does the DNA travel in the direction that it does?

17. Prelab Include the following: Group Members Problem/Purpose Statement
Hypothesis
Who do you think killed Mrs. Lewis and why?
Materials and Safety
Procedures (briefly summarized – not copied!)
Results Table (next slide)

18. Results Table HINDIII PstI ECORI Distance traveled BP Length *27,491
*23,130
9,416
6,557
4,361
2,322
2,027
**564
**125

19. When you come in… Collect your group’s gel and go to your lab benches.
On your data table…
Alicia Alvarez = EcoRI
Regina Carnes = PstI
Lauren Gastellum = HindIII

20. Discussion/Analysis Include the following:
An analysis of your data from the gel electrophoresis lab you performed
Graph of base pair length vs. distance traveled
Sources of error in the lab
In your discussion:
Suppose a DNA test that predicted your chances of getting a disease, such as cancer, were available. You take the test for cancer, and the results say you have a two in three chance of getting cancer sometime in the next 20 years. Who should have access to this information? Your doctor? Health insurance companies? Employers? Would you want to know this information?
Further applications of the technique
How are restriction enzymes used in gel electrophoresis:
Be sure to include a brief explanation of what restriction enzymes are, how they are used, etc.
Use the online lab simulation as a reference

21. How to Analyze Your Data
HINDIII
PstI
ECORI
Distance traveled
BP Length
*27,491
*23,130
9,416
6,557
4,361
2,322
2,027
**564
**125

22. On your samples Alicia Alvarez = EcoRI Regina Carnes = PstI
Lauren Gastellum = HindIII

23. The Graph X axis = distance traveled Y axis = base pair length

24. The Discussion
In addition to your discussion of your results and the criteria given in the initial lab report, please answer the following question:
Suppose a DNA test that predicted your chances of getting a disease, such as cancer, were available. You take the test for cancer, and the results say you have a two in three chance of getting cancer sometime in the next 20 years. Who should have access to this information? Your doctor? Health insurance companies? Employers? Would you want to know this information?