making metaphors{3}

This week, I am defaulting to a bad habit I have developed on Facebook. When I don’t have anything particularly interesting to post (which happens quite often) I do what many of my friends do – I post about my kids. For this blog, I’ll reference my ‘big kids’ (meant as a term of endearment rather than a diminutive), my students in Cell and Molecular Biology. I just finished grading Assignment 5, which contains one of my favorite pieces of the year. The subject is DNA replication, which can be conceptually challenging. How do the leading and lagging strands, which are oriented in opposite directions and must replicate in a specific direction (5′ to 3′) replicate simultaneously while the replication fork moves unidirectionally? And where do all those players fit in? DNA polymerase I, DNA polymerase III, topoisomerase, single stranded binding proteins, helicase?

I’ve always found that no matter which textbook I’ve adopted, only a subset of my students “get” DNA replication by looking at the figure in the textbook. I would provide figures from three or four different textbooks, and that helped a little. In recent years, YouTube offered some nice animations. But there were always students, quite a few, who still could not conceptualize DNA replication. Most science teachers employ metaphors. The human genome is the “book of life”, for example. After considerable frustration in trying to come up with the best  metaphor for DNA replication for my students, it finally dawned on me. DUH! Let the students make their own metaphors.

Here is where I step aside and let the work of my big kids speak for itself:

Laura, Caitlyn, Cari Lynn and Anna reminding us the ice cream is the answer to most of life's difficult questions.


Julie put her talents to work to crochet a fork complete with Okazaki fragments, RNA primer, SSBs (pins), helicase (scissors) and ligase (ribbon).


From last year, the team who called themselves Dumbledore's Army identified spells that could carry out the action of each enzyme on the fork.


Once again, Esther, John and Brandon managed to make us all hungry.



Lauren created "every Hokies favorite replication fork"


And just so my ‘little kids’ don’t feel left out, here’s a recent Facebook post about them. Just when I thought they had outgrown the kiddie pool, they invented a new game they call “Fast Turtle”.Fast Turtle