One thing that I really like about the education community is the willingness to share work, share resources and generally help each other out. I’ve often been offered full lesson plans or supplies from other teachers and I thought that I’d contribute in the same way. Occasionally, I’ll post activities or lesson plans, free for anyone to download and use. Here’s the first. This is a DNA extraction lesson plan that I developed by modifying lesson ideas that I found on the internet, talking to other people doing similar lessons, and then trial and error. I use it as part of my volunteering with the Let’s Talk Science Partnership Program (LTSPP) at UNB. I’m providing it as a Word document, so anyone who downloads it can cut and paste, modify and use the document as they see fit.

This lesson has been successfully executed in Grades 6 all the way to Grade 12. Personally, I’ve only done it with Grades 8 and up, but some volunteers at LTSPP have had success at Grades 6 and 7. The general idea is that you take fresh or frozen and defrosted bananas, grind them up using a blender, and then use a combination of some common household materials to extract and see the DNA. The one chemical that I usually get from campus is ethanol. I have heard, however, that rubbing alcohol can be substituted and the results are not as good, but it still works. 

As a possible extension, I’d suggest trying the same procedure on other fruits or on vegetables.I have tried spinach once, and it didn’t work – but you may have different results. Discussion of the scientific method, how experiments are designed, use of controls and so on would fit well here. The lesson plan also mentions an enrichment activity which involves using the genetic code to decode messages. Some messages to be decoded can be found here. Usually, I get the student to make lines after every third nucleotide letter in the decoding activity, and then place the one-letter protein code above each the three-letter codons.  The protein letters then spell out the messages. (I don’t worry about 5′-3′ vs 3′-5′, transcription, and translation specifically during this activity, but this could be added easily if you wanted.  I also encourage you to make up your own messages.) If you have any questions, please feel free to leave a comment and I’ll get back to you.