More Recent Comments

Tuesday, October 29, 2013

The Khan Academy and AAMC Teach the Central Dogma of Molecular Biology in Preparation for the MCAT

Here's a presentation by Tracy Kovach, a 3rd year medical student at the University of Virginia School of Medicine. Sandwalk readers will be familiar with my view of Basic Concepts: The Central Dogma of Molecular Biology and the widespread misunderstanding of Crick's original idea. It won't be a surprise to learn that a 3rd year medical student is repeating the old DNA to RNA to protein mantra.

I suppose that's excusable, especially since that's what is likely to be tested on the MCAT. I wonder if students who take my course, or similar courses that correctly teach the Central Dogma, will be at a disadvantage on the MCAT?

The video is posted on the Khan Academy website at: Central dogma of molecular biology. What I found so astonishing about the video presentation is that Tracy Kovach spends so much time explaining how to remember "transcription" and "translation" and get them in the right order. Recall that this video is for students who are about to graduate from university and apply to medical school. I expect high school students to have mastered the terms "transcription" and "translation." I'm pretty sure that students in my undergraduate class would be insulted if I showed them this video. They would be able to describe the biochemistry of transcription and translation in considerable detail.

There are people who think that the Central Dogma is misunderstood to an even greater extent than I claim. They say that the Central Dogma is widely interpreted to mean that the only role of DNA information is to make RNA which makes protein. In other words, they fear that belief in that version of the Central Dogma rules out any other role for DNA. This is the view of John Mattick. He says that the Central Dogma has been overthrown by the discovery of genes that make functional RNA but not protein.

I wonder if students actually think that this is what the Central Dogma means? Watch the first few minutes of the video and give me your opinion. Is this what she is saying?


John Harshman said...

I don't know that she's saying all that much, except that her version of the central dogma is explicitly "DNA makes RNA makes protein". I didn't hear anything about information flow, exactly, so I couldn't say that any other function of DNA would cause problems for this version. But clearly, reverse transcription falsifies it completely.

By the way, I'm surprised you didn't comment on the claim that, while proteins are made of amino acids, DNA and RNA are made of nucleic acids, by which she means the 5 bases.

judmarc said...

Cheer up, legal education is just as crappy. I still remember The owner of the largest US company in the bar review course business giving a video lecture of fundamental concepts in tort law, several of which he got horribly wrong.

(One example: The doctrine of res ipsa loquitur, "the thing itself," says that the very occurrence of a particular situation in itself shows negligence, so the plaintiff need not produce further proof, absent some counter-evidence by the defendant. The first case announcing the doctrine involved a man walking along outside a warehouse when a barrel rolled out of an upper story and smashed over his head. He was in no shape to gather evidence of conditions inside the warehouse at the time; it was held to be sufficient that the barrel had clobbered him, barrels flying out of upper stories of warehouses not being a thing that would ordinarily happen absent negligence.

Today, the doctrine can be used for situations such as surgical instruments left in the patient. The plaintiff was asleep at the time, but absent negligence forceps do not usually wind up leaving the operating room in folks' abdomens.

The lecturer said one should not use the doctrine of res ipsa loquitur for these sorts of situations, but rather should apply it to airplane crashes. After all, everyone knows a plane won't crash due to causes other than negligence, right?)

judmarc said...

Couldn't resist: