Summer Research Program for Science Teachers
Elmont Memorial Junior/Senior High School
DNA Fingerprinting through a Chemistry Lens
Aim: How does DNA Fingerprinting incorporate chemistry concepts?
Do Now: Draw an electrolytic cell used for splitting water into its elements.
What is necessary for this process to occur?
What types of charges repel? Attract?
How are mixtures separated?
Equipment: Water bath at 37°C
Hot plate with stirrer
Photography equipment- Polaroid.
Gel pouring box
20 uL micropipettors
Materials: DNA samples
Hind III (restriction enzyme)
1X TAE Buffer
Hind lIII DNA (as size standard)
Carolina blu DNA Stain
(note- all DNA materials can be purchased from Bio-Rad in an easy-to-use kit.)
Methods: Students will cut DNA with restriction enzymes. The fragments of DNA will then be separated by electrophoresis on an agarose gel. Students will see “whodunit” by analyzing the results. This lab will take 3-4 periods to run and analyze.
Overview of Time Schedule
Day 1 Review of DNA structure and function, Genetics, and basics of gel electrophoresis. (Students take biology before chemistry, so this should be a brief review.)
Preparation of 1X. buffer from 10XTAE solution.
Day 1 Lab worksheet
Day 2 Digestion of DNA with Restriction Enzymes, pouring agarose gel
Day 2 Lab worksheet
Day 3 Gel Electrophoresis- Loading and Running.
Day 3 Lab worksheet
Day 4 Analysis of results & discussion.
Day 4 Lab worksheet
Pivotal ?’s: How are stock solutions diluted?
What type of molecule is DNA? What type of bonding does it have, what properties?
How do restriction enzymes “cut” DNA?
During electrophoresis, why do the DNA fragments move?
What charge does DNA have? What electrode will it travel towards?
While the DNA is traveling, bubbles are forming, explain their presence in terms of chemistry.
How can you determine the size of a DNA fragment on the basis of the distance it has moved?
How is gel electrophoresis particle size sorting of a mixture?
What is a mixture that YOU could sort based on particle size?
What are the important chemistry concepts behind DNA profiling?
Summary: Review procedure - why is it important to understand DNA profiling?
How is chemistry integral to the process?
Who are the parents?
HW: Complete questions on handout, and post-activity reflection.