Restoring the American Chestnut
Author: | Shelley Casey |
Level: | High School |
Content Area: | Biology, Environmental Science |
Author: | Shelley Casey |
Level: | High School |
Content Area: | Biology, Environmental Science |
This simulation and manual PCR demonstration is designed for classrooms without a thermocycler and those that do not have enough time to do a full manual PCR. It is designed to give students the concepts and vocabulary as well as give them a visual representation of the process.
Students will be able to describe the process and product involved in a PCR reaction.
Biology Goal 3.04 – applications of biotechnology
60 minutes: Reading up to “Procedure” – 10 minutes, explanation of procedure -10 minutes, following procedure – 20 minutes, answering questions – 20 minutes
Per each student: Handout of “Lo-Tech PCR” activity
Per group of 2 students: Original DNA template (copied on blue paper, not cut out), forward primers (copied on yellow paper, cut out), reverse primers (copied on green paper, cut out), Ziploc bag labeled “Free Nucleotides” containing cut out nucleotides (A’s, T’s, G’s, and C’s) that have been copied on white paper, 1 pair of scissors, 1 roll of clear tape
Per class for demo: 3 water baths, 3 thermometers, bucket of ice, 1 microcentrifuge tube filled with water (students will be told this contains all necessary reactants for PCR; however, this is not necessary for this demo as it will not be used to run a gel electrophoresis), Styrofoam holder for centrifuge tube, test tube, deionized water, cotton swab, hot plate or microwave with beaker of water to hold test tube, glass stirring rod, 2 pair of student goggles
Overhead projector
Make a copy of each of the template sheets onto overhead film and cut out as it will be for the student set. You will be walking them through the first cycle. Make copies of activity for each student. Also, prepare copies of “Original DNA” template, forward and reverse primers and all nucleotides. Leave the “Original DNA” template intact to give to each group of 2, cut out the nucleotides individually and place them in the Ziploc and label. Finally, cut out the primers label the back “F” for forward and “R” for reverse. Paper clip these separately to make them easier to hand out. Set up water baths, one at 94oC, one at 48oC, and one at 72oC prior to class. Set up station for demo group using materials listed above. Be sure to have water in microcentrifuge tube prior to class. Students should already be familiar with DNA synthesis during the S phase of cell division as well as the structure and function of DNA.
Check responses to follow up questions for accuracy as well as the DNA pieces to make sure all 8 are identical or the original. Verbally assess students when papers are turned in to see that they understand what PCR means, what they steps are, what it produces, and what it can be used for.
Students with learning difficulties would benefit from having the section under the background paragraph read to them. This could be accomplished by having one person in each group of 2 read aloud or you could read and/or explain this section to the entire class. Also, show students how to calculate 2x if they are uncertain how to find this value on the calculator.
Once a “gene of interest” is located from studying phenotypes of offspring of an organism, that gene may be amplified for further study. PCR is the process of amplification. The next step would be to run the DNA through a gel electrophoresis and compare it to other known genes. These are initial steps for being able to use these genes for biotechnology products and processes.