Cells

All living things are made of cells.

The cell is the smallest unit of a living thing that still has the characteristics of the whole organism.

There are some single-celled living things, but most forms of life have many cells.

Very simple forms of life have prokaryotic cells.

The nucleus is not separate and organized.

The nucleus is all over the inside of the cell.

Living things with many cells have eukaryotic cells.

The nucleus is in its own spot in the cell.

Cells can last for a short amount of time or a long time.

For example, some white blood cells in your body last only a few hours.

Brain cells can last for your lifetime.

Your body has more than 10 trillion cells.