Protein Synthesis with Candy: I Won’t Take Credit, but It Worked

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.

Translating mRNA: Candy Edition

Translating mRNA: Candy Edition

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.

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3 Responses to Protein Synthesis with Candy: I Won’t Take Credit, but It Worked

  1. Pingback: Antibiotic-Resistant Bacteria: A Simple, Realistic Lab Activity | Teaching nonmajors biology

  2. Jessica Ardis says:

    I did this with a class of 100 students. I put kits in ziploc bags and gave them to each group of 5. On the screen I defined what each piece represented. I wrote a DNA sequence which was 9 bases long. I wrote up a worksheet which asked questions as they made DNA, mRNA, tRNA, and protein. I used gummy bears for the bases and assigned one color to each. Gummy bears are actually good because they come in 5 colors. I gave them a 2nd and 3rd sequence which contained a silent and a missense mutation. What I realized as I was running around the room trying to help 20 groups was that I needed 3-5 assistants! Also 50 minutes was not enough. I needed the whole 80 min as students had more trouble with this than I anticipated.The thing they had the most difficulty with was tRNA. All in all I will do it again, but leave a whole class period (80 min.) Since I don’t have TAs I will have the strongest students circulate around the room as helpers. Also I spent almost $40 on the supplies, but I was happily reimbursed! Thanks for posting this idea!

    • Hi Jessica! Thanks for the idea about the gummy bears. The colored mini-marshmallows are hard to tell apart, and nobody wants the leftovers when the activity is done. I am sure I will have no problem unloading leftover gummy bears though. And I can relate to the bottleneck with tRNA. I think a lot of students learn from that stumbling block though, and they subsequently remember how tRNA is put together after they have struggled with that part of this activity.
      Thank you for sharing your experience with this!

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