Transcription and Translation Modeling in Biology

4 different already "Unzipped" DNA strands 

When deciding what we'd do in class to help students understand the process of transcription and translation several blog posts gave me inspiration.  I had just done the transcription translation lab from Kim Foglia in AP Bio and I read these posts on making proteins out of beads on the Science Matters blog. Inspiration struck to combine these two labs into one for my class.

RNA nucleotides ready for transcription

I started the process backwards, by deciding which amino acids would be in the finished proteins. Since the pack of beads I already had at home only had 7 different colors, there were only 7 types of amino acids in our proteins. Two of the designed proteins were identical. I wanted students to be able to see that two strands of mRNA with different orders of nucleotides could produce the same protein because there are multiple codons that code for the same amino acid.  The visual also helps during discussions of silent mutations.

Using DNA as the template for transcription

Next, I wrote the mRNA code for each protein, making sure that I used different codons for the amino acids in the matching proteins. Then I wrote the DNA code that would be transcribed into our mRNA strands.  I felt a little like reverse transcriptase as this point! Now that I had all of the codes I wanted, it was time to prepare the model materials,

I made the beaded proteins and labeled them with a number and set them aside as an answer key for students to check when they were finished. I used a sheet of DNA molecules from Biology Corner, and used the RNA nucleotides from Kim Foglia's lab.  I color coded each DNA nucleotide we would use in the lab, laminated them, and lined them up in the correct order for each of the 4 DNA strands that we would start with in the lab. I taped the line of DNA together with two long strips of packing tape-one on the front and one on the back.  I wanted to make sure it was super sturdy since I wanted it to last for several years (OK, true confession, I want them to last forever). This was time consuming, but hopefully won't need to be repeated any time soon (unless someday I have a class with more than 4 lab groups).

Amino acids ready for translation

Kim Foglia's RNA nucleotides fit perfectly with the DNA from Biology Corner, so I printed each type of nucleotide on a different color paper and laminated them before cutting them all out. These I just put in containers for students to take as they are modeling the process of transcription as they build their mRNA molecule.  Since each RNA nucleotide (A, C, G, and U) is a different color, it's easy for us to hold each lab groups' finished mRNA molecules together to compare them.

After they finish transcribing their mRNA molecules, students move onto translating the mRNA code into a protein. Once the proteins are made, we can compare them. We focus on protein 1 and 4, which match. Then we go back to the mRNA molecules and observe that they are not the same.  At this point we can look at the codon chart, talk about multiple codons for the same amino acid, and what it means to have a silent mutation.

Comparing mRNA from strand 1 and 4 since they built identical proteins 

Here's the link to the student lab. And here's the link to the lists of DNA, mRNA, and protein strands.