doc w/ Pen

journalist + medical student + artist

The Joys of Mutation: Manipulating The Lac Operon

Gene Machine: The Lac Operon

Click to Run

When I was homeschooled (preschool – 5th grade), my mom was all about interactive learning. We dissected animals, performed chemistry experiments, baked cookies to learn about adding fractions, all kinds of things. It made learning fun, and it made the learning stick. My love of interactive learning has continued, and it’s one of the reasons I love my science labs – we put into practice the skills and concepts that we have developed in the classroom.

Last week, my Genetics professor, Dr. Kreher, was able to bring that flavor of interactive learning into the classroom as well. We were learning about gene regulation, more specifically, E. coli’s lac operon (the set of genes and other elements that control for the breakdown of lactose, which is a source of energy for the bacteria in certain environments, including our digestive tract). Dr. Kreher had found a lac operon computer simulation program – which is free – that you can manipulate to see what happens when you “mutate” (i.e., remove) certain elements, add lactose, etc. It really made the system come alive, and I now understand the operon in a way that I had not before (in spite of the fact that I have studied it in past courses). I have included a link to the program in this post (just click on the picture above where it says “Click to Run”). While simple in terms of graphics and operation, it really represents how this system works, and what gene regulation means. I highly recommend checking it out. Have fun mutating!


This is an example of what I’ve been working on today …
the reaction to the left is called halogenation; the reaction
to the right is called halohydrin formation.

After hours of wrestling through organic chemistry problems (and getting so many wrong) … breakthrough! I think I’m finally getting it. Reaction mechanisms, that is. Well, not ALL reaction mechanisms, just the handful that we’ve studied thus far this semester. (The mechanisms of SN1, SN2, E1, E2, hydrohalogenation, hydration, halogenation, halohydrin formation, and hydroboration-oxidation, to be more specific.)

This morning, when I started studying for my organic chemistry final, it was all a mish-mash to me. Anti addition, syn addition, retention of configuration, racemization, carbocations, bridged halonium ions … I couldn’t keep it all straight. But after making (and reviewing) a huge batch of flashcards and working through gobs of these practice problems, something has clicked. Just now, I found myself looking at a reaction and actually knowing what to do with the bonds, atoms, and electrons. What arrows to draw. What products (including stereoisomers!) would form.

I still have a lot of practicing to do. I don’t have all of these reactions down completely. But I’m getting the hang of it, slowly. Thankfully, my organic chemistry final isn’t until next Friday, so I have plenty of time to cement my understanding. But knowing that I am already on my way is a darn good feeling.