We have been studying protein synthesis over the past couple of weeks. In my experience, students find the details of the process difficult to remember; the role of tRNA (and its mysterious anticodon) seems especially hard for them to grasp. I have tried various tactics to help students understand how the parts interact, including concept maps and white board drawings. But I wanted to try something new at last week’s Action Center.
I have a small grant that allows me to buy snacks for my Action Center, and a student suggested finding candies that could be combined with “protein synthesis” practice. A quick online search, plus a bit of thinking on my part, convinced me that was a good idea. Here’s the recipe I settled on:
- Red and black Twizzlers: RNA and DNA backbones
- Colored and white mini marshmallows: A, C, G, T, and U
- Jumbo marshmallows: tRNA
- Assorted wrapped miniature candy bars: amino acids
- Toothpicks: covalent bonds and/or hydrogen bonds
The only instructions I gave were: (1) Make a double-stranded DNA molecule consisting of 15 base pairs. (2) Designate one of the strands as your template strand. (3) Transcribe your template strand to mRNA. (4) Translate your mRNA to protein, using tRNA (complete with amino acid and anticodon). I provided a genetic code, but with these instructions they didn’t really need it.
The photo included with this post shows one group’s model. Overall, students enjoyed the activity and reported understanding the role of tRNA much better.
I will definitely do this again in future semesters. Next time, however, I will assign each type of candy bar to a specific amino acid, and I will specify the initial DNA sequence. That way students will have to consult the dictionary of the genetic code, which will reinforce that the code is read from the mRNA, not the anticodon.
I will also instruct the students to leave the mini-candy bar wrappers on, as they had a hard time telling the bars apart once they were unwrapped. Finally, you might have noticed that it’s hard to distinguish the different mini-marshmallow colors in the photo. That’s true even in real life; the pink and orange ones are really similar. Jujyfruits or Dots might work better (and they come in five bright colors, perfect for those five types of nucleotides).
Can you think of other ways to improve this model? If so, please share them in a comment.