DNA to RNA to Protein

This frog’s DNA works the same way yours does.

Yesterday I was thinking about how much I love the central dogma of molecular biology.

“Central dogma” is a funny name for it. It sounds like it has something to do with religion, but it’s not; it’s just the thing that makes all living cells work. A cell has DNA; that DNA has a code, which gets transcribed into the almost-the-same-but-not-quite code of RNA; and then that RNA gets read and used as a template for building proteins. This is happening all the time in all living cells–the cells in the skin on your right ear, the cells in your pancreas, the cells in the rootlets of the plants outside, the cells in a polar bear’s liver.

It’s so simple and yet it’s so complicated. There are a lot of kinds of RNA. There are a lot of kinds of DNA. When DNA gets transcribed and when it gets ignored is really important, and people are still figuring out just how that works.

The elegance of the basic process, though – at some point that sank into mind, and I guess into my heart, and stayed there. When someone I’m interviewing says “transcription” I have any number of diagrams from biology textbooks that contributed to the image, the scaffold in my head where I can hang whatever new information they give me.

One of the things that I have to think about constantly, as a science writer, is what my audience knows. After decades as a really big fan of biology and 15 years as a health and science writer, I know a lot. But I have to keep one foot firmly planted in that sense of what my audience–often the general public–knows. And I’m pretty sure the central dogma isn’t something the general public knows.

This is not something I hold against the general public. Not at all! I don’t think most of us know much below the surface of other fields. Don’t ask me which Romantic poet is which, or how to tell the difference between landscapes sculpted by wind or by water. (Actually I’m not that bad on Romantic poets. Non-Western literature, I’m terrible at that.) The general public knows genes are important, and that’s all they need, day to day.

I do wish more people know about the central dogma. It’s just so nifty and so simple and lovely.

I also wish people knew that proteins do basically everything in your cells. Did you know that? Proteins aren’t just, like, a thing you eat, or what forms the bulk of your muscles. The reason they’re so important, that the process that leads to them is called the “central dogma”, is that they have jobs. It’s proteins that bring other molecules together so they can react; those proteins are called enzymes. Other proteins are receptors. Proteins are the ones that decide what kind of stuff can get in and out of a cell. Genetic diseases cause problems by messing with the instructions for making one protein; without it, you don’t work right. Insulin is a protein. Proteins do structural jobs, too–your hair is protein, and your fingernails. And, yeah, proteins make your muscles work.

So spare a thought for all those little molecules, doing their jobs in all of your cells. It’s a wonderful world, isn’t it?

Image: Wellcome CollectionCC BY


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