Tag Archives: stop codon

Central Dogma: Cystic Fibrosis Case Study

In today’s lesson, we used a case study about cystic fibrosis as the mechanism to:

  • review the stop codon;
  • connect the concepts of protein structure and function;
  • review how R groups differentiate amino acids;
  • review how R group interactions result in protein folding;
  • discuss “structure equals function”;
  • bring a human face to a genetic disease;
  • and help students recall the mechanism of genetic inheritance.

For the entry task, students were challenged to consider how genes begin and end.  We discussed how mRNA sequences always begin with AUG (which codes for methionine, and amino acid which may also occur elsewhere in a protein).  Students were then reminded of the three “stop codons” and we reviewed how those work to release a protein from the ribosome.  We reviewed the structure of amino acids, focusing on the 20 different R groups and how those R groups each have different properties.  The interactions between R groups determine protein shape, and shape determines protein function.  When the sequence changes, the shape changes, thus changing the function of a protein.  We then moved into the cystic fibrosis case study, first watching the video below and then working through the lesson PowerPoint.

Pictures from the white board today:

Central Dogma: Case Study of Cystic Fibrosis

Because of the short week, today was a full schedule Friday.  We took advantage of the longer class period by learning about the stop codon, focusing on cystic fibrosis as a model disease caused by a genetic mutation which introduces a premature stop codon in about 10% of people with CF.  After watching an inspiring music video about a 15-year-old young man with CF, students learned more about the disease and genetic mutations in general.  We finished with a game where students practiced converting amino acid sequences to RNA and then replacing individual bases to create stop codons.  The lesson plan, along with example sequences from the game can be found here.