ribosome

In the 1950s, scientists knew proteins were being built inside cells, but they didn't know where or how. In 1955, electron microscopy finally revealed tiny particles on the endoplasmic reticulum—granules that looked like beads on a string. These were protein factories. In 1958, at a meeting of the Biophysical Society, Richard Roberts proposed the name ribosome: ribonucleic acid (RNA) + soma (body)—a body made of RNA.

Ribosomes are extraordinary machines. A ribosome reads messenger RNA—a copy of genetic instructions from DNA—three letters at a time. For each group of three letters, the ribosome grabs the corresponding amino acid from the cytoplasm. It stitches the amino acids together in sequence. A few seconds later, out pops a new protein.

A single cell contains millions of ribosomes. Every second, they're reading messages and building proteins. Bacteria have smaller ribosomes; eukaryotes have larger ones. Ribosomes are so fundamental that all living things have them—it's one of the few things that connects every organism from viruses to blue whales.

The ribosome is perhaps the most important machine ever to evolve. Without ribosomes, there are no proteins. Without proteins, there is no life. When antibiotics kill bacteria, they often target ribosomes—a brutal way of saying: if you break the protein factory, the bacteria dies. The name ribosome carries the weight of that power.