do you think mutations occur at the individual level?
How do you think these mutations might affect us as individuals?)
1. As students enter the room, assign them the roles of mRNA, tRNA, ribosome.
Have the DNA cards taped to the front board and labeled NUCLEUS. Have the anti-codon
cards on a table in another part of the room. Cards can be lumped together
or spaced out by the initial letter on each anti-codon card.
2. Ask students to think back to their study of the cell. Ask for volunteers
to remind the class about the function of the mRNA, tRNA, and ribosomes.
3. Tell students, “Today we will be simulating the synthesis of proteins.
You will be in groups of three. Each group will need one mRNA, one tRNA, and
one ribosome. Together, your group will compete against the others to try to
correctly transcribe and translate as many proteins as possible. Since the
DNA is located in the nucleus, the DNA cards must remain on the board. The
student simulating the mRNA will come to the board, read the DNA code, and
encode into RNA. (Remember that there is no T in RNA) The strips of code written
by the mRNA will be passed to the ribosome. The ribosome will then read the
RNA and write the anti-codons. (Remember that there is no T in RNA). Once the
ribosome has done its job, the strip is passed to the tRNA. The tRNA will go
to the anti-codon cards and search out the words (proteins) that correspond
to the anti-codons. The tRNA will then bring the protein to me. If correct,
the team gets a point, if not, they must begin again. (Remember that all sentences
begin with the start (AUG) and end with the stop (TAG) codon. Good Luck.”
4. Allow students sufficient time to translate and transcribe several “sentences.” Students
will bring you incorrect/mutated sentences. These are wonderful examples of
mutations and should be saved to discuss at the end of class.
5. Bring the students back together. Ask students “What were the challenges
that faced each person? Where were mistakes or potential for mistakes made?”
6. Ask students, “When we are talking about errors in DNA, and protein
synthesis, what do we call mistakes? [Mutations] Are these mutations going
to affect individuals or the entire species? [Individuals] Why? [Because the
mistakes occurred during translation and transcription, not during the creation
of haploid (sex) cells]