A simplified model of the ETC, custom built in Mindnode Pro.
I just got back from the NABT (National Association of Biology Teachers) professional development conference in Atalanta, GA, and two things stuck out. One, I love teaching biology (and I love to talk about teaching biology); and, two, I’m on the right track. I may be a bit behind the curve when it comes to generating digital content for a wide audience, but I am ahead of the curve when it comes to engaging my students in fundamental science using a mix of high tech, and high touch, approaches. I’m going to use this post to describe how I do this. Hence, this post’s title. Usually I’m just riffing on how I teach. Here I’ll attempt to walk the reader how I use original content to teach a fundamental concept.
If you know anything about me, it’s that I can’t separate teaching philosophy (or pedagogy) from teaching itself. I’m currently teaching bioenergetics (one of my favorite units), and I am continually reminded of one of the eternal truths of teaching: knowing something is useless, if you can’t communicate the idea. Bioenergetics is one of the best examples of this philosophy. I know this stuff, I’ve spent years thinking about it, wrestling with it, and trying to understand it. I’m equally interested in figuring out how to communicate these complex ideas to students so they too can understand them. Below, I’ll offer my insights on how I’ve made these complex ideas more digestible for students.
First, take a look at the image at the top of this post. It’s my version of the electron transport chain (highly simplified, of course), with out all the background noise found in many text books. Second, look at the marked up image found at the bottom of this post. I project images like the one featured above and draw all over it with dry erase markers all the while asking students questions about what’s happening within each step.
Today I realized I teach oxidative phosphorylation (or OXYPHOS) as a four part story. Here I take a very complex concept and communicate it in a simple way to increase student understanding. Before I tell the story, you’ve got to realize a couple of things: I expect my students to retain information they learned previously (even years before — in pre-AP Biology), and I expect my students to draw upon their experiences in lab (for more on the daily flow of my class, visit jcibapbiology.wordpress.com to see what we’re doing).
Now for the story. During Part 1, protein complexes oxidize electron carriers (NADH and FADH2), and then electrons are pulled down the electron transport chain (ETC) in the presence of oxygen. In part 2, electrons flow down the ETC. These reactions release energy, and this energy is used to transport H+ from the matrix into the inter-membrane space. Part 3: when H+ are actively transported across the inner membrane, H+ ions are packed into the inter-membrane space, and a chemo-electric gradient is established along the inner membrane of the mitochondria. In part 4, ATP synthase taps the chemo-electric gradient to phosphorylate ADP into ATP. Part 4 has a specific name: chemiosmosis. In this particular case, chemiosmosis is a coupling mechanisms that links the catabolic release of energy from NADH and FADH2 oxidation to the anabolic synthesis of ATP from ADP and inorganic Phosphate (Pi).
This is a fairly wordy story, but if students understand it (both in words and pictures), and if students can relate this story to the greater context of cellular respiration, then they understand the fundamentals of heterotrophic metabolism. Below you will see an image of the marked up version of the initial diagram from 25Nov13.
Simplified ETC with the “Reardon Treatment”
Days like today are quite satisfying. I taught my students something they never knew before. I deepened their understanding of essential, complex, processes. One of my brightest, and most skeptical, students said, “That was a cool lesson.” I continued to optimize a lesson I’ve been teaching for over 12 years.
This is a pivotal moment in my IB Biology class. Today I pushed students to apply lots of related concepts (re-dox, active transport, facilitated diffusion, pH, metabolism), I taught them something new about mitochondria…and I pointed them to the future: our investigation of mitochondrial genetics coming in January 2014.