From small molecules (a billionth of a meter in length) to whole plants and animals, there are some
things that all living things have in common. One of them is the requirement for energy. Biology uses
a special molecule called ATP to provide energy for cells. Here we will show you how ATP is made in
cells, in special compartments called mitochondria. Cells use this energy for many important jobs,
including fuelling the movement of immune cells around our bodies to fight infection. You’ll see how
energy stored on a microscopic scale is used to power whole organs and organisms.