Explainer: The Central Dogma

by Clarice on flickr

Today it’s raspberry walnut tart. I find the recipe on my computer, then jot down the ingredients and instructions on a 3”x5” card. I hurriedly take the recipe card to the kitchen where I begin collecting the ingredients – butter, flour, sugar, red raspberries and chopped walnuts. After 2 hours of mixing, kneading, spreading, baking and patient waiting, the tart is ready. And it’s delicious!  I like cooking for two main reasons: it gives me time to de-stress after work, and it gently reminds me of the basic biology which my thesis research is founded on.

The DNA contained inside each of the cells in our bodies is like an extensive cook book, called a genome. It contains thousands of recipes, called genes, which instruct our cells how to make proteins (instead of raspberry tarts). Because this recipe book of DNA is the essence of life, it is stored in a heavily guarded library in our cells, called the nucleus. In order to cook up a protein, our cells must first copy the recipe onto a recipe card, called RNA.

The act of copying the DNA recipe into an RNA copy is called transcription. This recipe card of RNA is then sent out of the library and over to the cell kitchen, the endoplasmic reticulum (ER). Small structures on the ER called ribosomes read the recipe copy, gather the ingredients and mix them together. Sometimes multiple ribosomes can read one recipe copy in succession, thereby doubling or tripling the batch of protein made. This process of reading the RNA and making a protein is called translation.

After translation, the protein is cooked so that the ingredients meld together, an action called protein folding. Without this step, the protein would be an inedible glob of dough instead of a delicious tart. The final step, called protein modification, is where the protein will get final touches, like a sprinkle of powdered sugar or a dab of icing. Collectively, these steps are the fundamental basis of biology, and are endearingly referred to as the central dogma.

Now that you’ve got this down, you will be able to understand other details of cell biology, so dig in!