Engage

Students may be asked to think about how genetic code might be deciphered and why it is important. Teachers may introduce Nirenberg and Matthaei's work through a short video or relevant reading for students to gain a basic understanding of the process of deciphering genetic code.

Explore

Students may conduct a preliminary exploration on the model. They may input various combinations of nucleotides (A, C, G, & U), synthesize and translate mRNAs, and examine the involved codons and amino acids. In this phase, students may learn how to use the module and how it works. They may also realize the level of complexity of cracking genetic code.

Explain

After students gain a certain familiarity with the module and process of cracking genetic code. The teacher may let students consider how to crack genetic code more strategically. The teacher may guide students to consider the following strategies:

• Start with the codons containing fewer types of nucleotides, e.g., UUU, AAA, CCG, etc

• Work collaboratively

Then the teacher may put students in small groups and assign only two nucleotides to each group. The teacher may assign the same two nucleotides to two groups to compare results. A big blank genetic code table may be used for whole-class sharing and discussion. Deciphering genetic code can be intensive and exhausting. The teacher may let students work for 10 minutes and then have them share their results on the blank genetic code table. It is very important for them to articulate the evidence and how it determines the code. When students come up with different amino acids for a codon, it will be a great moment for a discussion. When students learn from each other through class sharing and discussion, let them work for another 10 min.

Extend

The teacher may add the start codon "AUG" into an mRNA and let students translate the sequence, or discuss the degeneracy of the genetic code based on students' results.

Evaluate

Depending on students' results, the teacher may ask students to determine the amino acid for a codon that has not been cracked in class. Ask students to write a paragraph to explain how they determine the amino acid.