Ribosome

A complex organelle (composed of proteins plus rRNA) that catalyzes translation of messenger RNA into an amino acid sequence. Ribosomes are made up of two non-identical subunits each consisting of a different rRNA and a different set of proteins.

Electron

A fundamental physical particle with negative charge. A component of atoms.

Nodule

The enlargement or swelling on roots of nitrogen-fixing plants. The nodules contain symbiotic nitrogen fixing bacteria.