What is it?

A cell is the basic structural unit of all living things.

All cells are surrounded by a cell membrane that protects it from the environment outside. It lets nutrients and other substances into the cell, and lets waste material out.

The cells of plants, animals and fungi contain a nucleus, in the middle of the cell, where DNA is housed. DNA contains the information necessary for cells to copy themselves exactly, or reproduce.

In between the cell membrane and the nucleus is the cytoplasm, a fluid that contains other small structures that carry out a variety of tasks, such as digesting nutrients.

Which species have them?

All living things are made up of cells, which are sometimes called the ‘building blocks’ of life. The earliest organisms on earth, billions of years ago, were made up of just a single cell, and so are many that are still alive today, such as amoebae and bacteria.

Complex organisms like humans contain trillions of cells. These have the same basic structure as the cells of single-celled organisms, and of all other life forms. This is evidence of our shared ancestry.

Alternative cell structures

There are many differences between cells that have different functions, such as muscle cells and skin cells.  There are also differences between cells in different organisms, such as plant cells and animal cells.

Plant cells contain chloroplasts, which are used in photosynthesis. They also have a cell wall in addition to the cell membrane.

Cartoon image of a stegasaurus disappearing through closing door

The first collected specimen of Theobroma cacao, the plant from which chocolate is made, is kept in the Museum.