protein

A protein is a long chain of small building blocks called amino acids, folded up into a specific 3D shape. That shape is the whole point: it lets the protein do a real job inside your cells — speeding up chemical reactions, holding your tissues together, carrying signals, or fighting off invaders.

Your DNA is basically the instruction list for which amino acids to string together, in what order. Once the chain is made, it folds — often in fractions of a second — into a precise twisted, knotted shape. Change the shape and you usually change (or break) the job, which is why a single wrong amino acid can cause disease.

For decades, predicting how a chain would fold from its sequence alone was one of biology's hardest puzzles. In 2020 an AI system called AlphaFold cracked it well enough to predict shapes for nearly every known protein — a breakthrough that won a share of the 2024 Nobel Prize in Chemistry.