Cell biology is the scientific study of cells, the tiny living units that make up all plants, animals, and other organisms. Every living thing, from a single bacterium to a blue whale, is built from cells. Some creatures are just one cell, while your body contains roughly 37 trillion cells working together.

Cell biologists investigate how cells function, grow, divide, and communicate with each other. They study the different parts inside cells, like the nucleus (which stores genetic instructions), mitochondria (which produce energy), and the cell membrane (which controls what enters and exits). They examine how healthy cells work and what goes wrong when cells become diseased.

This field has led to crucial discoveries. Cell biologists figured out how cells divide to create new cells, how they use DNA to make proteins, and how diseases like cancer occur when cell division goes haywire. Their work helps doctors develop treatments for illnesses, helps farmers grow better crops, and helps scientists understand how life itself operates at its most fundamental level.

The word cellular means relating to cells. When you hear about cellular respiration, that's the process cells use to convert food into energy inside the cell.