In this exercise, students recreate the protein production pathway from the nucleus all the way to the cell membrane for exported proteins. I supply them with pieces of string and beads to represent the sugar-phosphate backbone and nitrogenous bases of nucleic acids and a snake puzzle to represent a chain of amino acids.
They start by building a model of DNA with the direction to focus on the accuracy of their model. Despite having a clear figure in the text illustrating the complementary nature of base pairing, it’s surprising to me how many groups in each class fail to show complementary pairs, in this case, colors, in their model of DNA (A-T and C-G). It’s likely that this is simply due to lack of experience in making models.
Then they’ll make a copy of a segment of DNA onto a strand of mRNA which codes for the amino acid sequence. These amino acids fold into a three-dimensional shape. At this stage of the class, they can simply fold the puzzle into any shape they can create. Comparing the final protein across groups, the students see that there is an incredible diversity in shapes. This exemplifies the flexibility in form by proteins.
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