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Monday, October 20, 2014

How not to teach biochemistry

One of my friends is teaching introductory biochemistry and he thinks this video (below) is worth posting on his blog [here]. I do not want MY students to think that this is the right way to understand glycolysis and the citric acid cycle.


Better Biochemistry
  1. Accuracy: The top three criteria for effective teaching are; accuracy, accuracy, and accuracy. If what you are saying isn't factually correct then nothing else matters. The citric acid cycle shown in the diagram is pretty good. It avoids the most important error (using FADH2 as the product of the succinate dehdrogenase reaction) but it commits the three other, less significant, common errors [Biochemistry on the Web: The Citric Acid Cycle].

    However, when the song gets to the succinate dehydrogenase reaction (at 1:55) it points to QH2 and calls it FADH2. If you are going to teach about these reactions then get them right.

  2. The Evolutionary Approach: There are several ways of teaching biochemistry. The American Society of Biochemistry and Molecular Biology (ASBMB) recommends an emphasis on evolution [ASBMB Core Concepts in Biochemistry and Molecular Biology: Evolution]. This may seem obvious in the 21st century but very few biochemistry courses are taught this way. Most of them adopt some version of the "fuel metabolism"1 approach to teaching biochemistry. This approach focuses on human metabolism without putting it into the large context. The video is all about "popping carbs" as though converting carbohydrates (glucose) to energy was the only reason for having these pathways.

    This approach caters to the biases of the students and to the pre-meds in the class. It does not take the opportunity to correct some of those biases.

  3. Basic Concepts: ASBMB has come out strongly in favor of teaching core concepts rather than memorize/regurgitate [ASBMB Core Concepts in Biochemistry and Molecular Biology]. While I don't always agree with their core concepts, I strongly support this way of teaching biochemistry. The emphasis in a course should be on understanding the basic principles and not on memorizing the details. When I was teaching this material, I allowed students to bring their notes to the exam so they could refer to the specific reactions of the various pathways. They did not have to memorize them.

    The core concepts here are things like the importance of gluconeogenesis and why some species have evolved ways of "reversing" that pathway. It's also important to understand the thermodynamics of the reactions in a pathway and the fact that most reactions are at equilibrium. This leads to an emphasis on flux. With respect to the citric acid cycle, the core concepts are that all of the intermediates are involved in multiple reactions and in most species there's no simple "spinning" of the cycle spewing out CO2. Once they grasp that, you can teach teach them what happens in active mammalian muscle cells. It's harder to make a rap video about core concepts.

    You should never, ever, ask students to memorize these reactions for exam questions. No only is that a waste of time but it detracts from the main goal, which should be learning fundamental principles and concepts.

1. Also known as "rat liver biochemistry" since most of the information comes from studies on rat livers.


Athel Cornish-Bowden said...

"The top three criteria for effective teaching are; accuracy, accuracy, and accuracy."

This is plausible, but I'm with Keith Laidler, who listed the criteria as "Correctness, cogency, clarity, these three, but the greatest of these is clarity." You won't like the echo of St Paul, but I think he was basically right (Keith, not St Paul). Inaccuracies that are presented in a clear and understandable way can be corrected, but if they are presented in a vague or muddled way it can be very difficult to eradicate them.

Larry Moran said...

The primary goal is not to teach inaccuracies in the first place. Whether you teach false information with clarity or not is irrelevant. A teacher who presents an accurate view of, say, evolution, in a muddled manner is better than a slick performer who teaches creationism with clarity.

Joe Felsenstein said...

I'd watch out for false dichotomies here. Otherwise the two of you will manage to be both unclear and inaccurate.

Larry Moran said...

It is not a false dichotomy to decide that accuracy is more important than clarity. We've been rewarding style in teaching for far too long. Several Professors in my school have won teaching awards even though what they teach is wrong and/or misleading. I want to put more emphasis on accuracy and less on style.

We even have courses that train Professors in acting so that they can give a good performance at the front of the class. Nobody seems to care WHAT they teach as long as they do it with pizazz.

judmarc said...

As a student:

- Lack of clarity will result in students learning nothing (most likely), with a few outliers getting either the wrong idea or the right idea. Virtually no one will be excited enough to pursue the subject further.

- Clarity with inaccuracy will result in most students getting the wrong idea, though a few outliers might be perceptive enough to get it right. Perhaps a handful of students will be excited enough to pursue the subject further, and they may eventually learn the correct information.

Thus short term, lack of clarity will have better results. Long term, inaccuracy may, as far as potential contributions to the discipline by students are concerned.

Athel Cornish-Bowden said...

I think judmarc has it basically right, and of course in reality we have to strive for both accuracy and clarity.

Next Monday I have to give a lecture in Paris on a topic (single-molecule experiments) on which I have very little expertise. I told the organizers of the course that I really wasn't an expert and they ought to find someone else. However, they were very insistent and eventually twisted my arm enough for me to agree. So, what to do?

Strategy 1: Try to be as clear as possible but admit at the outset that I'm likely to get some things wrong, so students shouldn't just blindly accept what I say if it doesn't seem right, but should go away and read some papers. If they don't understand something they should stop me and we can try to work it out. However, French students never do that so I'm wasting my breath telling them to. It's a joint course with the Université de Montréal (by video-conferencing), but although previous experience with Canadian students suggested that they are more willing to open their mouths than French students are there was no evidence of that in the (very elementary) opening lecture I gave to the same students several weeks ago .

Strategy 2. This one is often followed by poor professors who have to teach stuff they don't know very well. Admit nothing, and make the presentation sufficiently muddled and unclear that students go away thinking they are too dumb to understand rather than that the professor is to dumb to present it properly.

I hope I don't need to say which strategy I plan to follow.

judmarc said...

I hope I don't need to say which strategy I plan to follow.

Which raises another important point about why a dichotomy between clarity and accuracy may be more notional than real: Professors who don't know the material very well can seldom be tremendously clear about it. Whether the reverse is also true (those who know the material well enough to be quite accurate also know it well enough to be clear in their descriptions) is something I'll have to think about.

SRM said...

Of course there are bound to be professors who know the material inside out accurately, but lack the ability to communicate it effectively, especially when the sophistication of the material must be geared toward a target audience (eg. 2nd year undergrads vs grad students). Then there are the uninspired droners who understand their target audience and teach accurately, but still manage to make interesting topics seem boring (which risks turning each face to the electronic device each student carries in their hand these days).

Anonymous said...

Are you ever going to answer this issue about what you meant about the "active designer"? I think you should do it sooner rather than later Joe...This is my last request... I have given you adequate opportunity to respond.... I feel... you know what come in next....

Joe Felsenstein said...

I think that was 116 in the Whotta Jerk series. As to what comes next, well that would be 117, of course.