Central Dogma: Initial Ideas

We began the new semester with a review of the Unit 2 Exam from last Thursday.  Students received their graded exams and we went over how the exam was scored and how the final scores were curved.  We went over the procedure writing question in detail, with students revising their procedures to better meet the criteria for writing a successful EOC-style procedure.  The procedure for the experiment was outlined on the white board, variables were identified, and students then were instructed to add the important missing details to make the procedure reproducible.

We pivoted to a brief acknowledgement of the Iowa caucuses this evening, with students voting on whether to keep the original grading system (second semester grades = the average of third and fourth quarters) or transition to a semester-long grade book.  After the final votes were tallied, students decided bya 48-40 margin to transition to the semester-long grade book.  Finally, we concluded class with an exit task where students were instructed to write down everything they know (or think they know) about DNA, genetics, inheritance, and related concepts.  After some private think time, student ideas were captured on a class poster, where each student was asked to contribute a unique idea.  The posters will be displayed and periodically updated to reflect new student learning as we progress through the new unit.

Molecular Structure and Properties: Mirror-Image Isomers

Welcome to second semester!  We have a few new students joining our class, so we will briefly review the syllabus (with minor revisions), talk about class mechanics, and consider opportunities for fine-tuning how we use our new textbook this semester.  Next, we will dive into Lesson 47 and investigate the concept of mirror-image isomers, also known as chiral compounds.  We will begin with the Lesson 47 PowerPoint ChemCatalyst to help get students thinking about mirror images.  We will then watch a short video about chirality (below):

Students will then receive the Lesson 47 Worksheet, working in pairs to model the compounds using the class set of molecular modeling kits.  The worksheet concludes with students hypothesizing whether L-carvone will smell like D-carvone, and then testing their hypothesis.  For homework, students were assigned textbook questions 2, 7, 8, and 9.

Want more?  Check out the blog post Perhaps looking-glass milk isn’t good to drink for an overview of Lewis Carroll, looking-glass milk, and L- and D-carvone.  Want more?  Joanna Shawn Brigid O’Leary from Rice University published an even more extensive investigation of how Lewis Carroll (author of Alice in Wonderland and Through the Looking Glass) weaved biochemistry into his fiction.  Her paper (available as a PDF), WHERE ‘THINGS GO THE OTHER WAY’: THE STEREOCHEMISTRY OF LEWIS CARROLL’S LOOKING-GLASS WORLD is well worth the read.  Perhaps it will even inspire students to read the book before the movie is released in theaters on May 27!