What is a cell ?
All living things—plants, animals, and people—are made of cells. I
am made of cells.
A cell is the smallest living part of me it is possible to imagine. A
cell can be long, short, thin, fat, square, or round. It is made of a
soft jellylike material called protoplasm. A cell is so small it can be
seen only through a microscope.
All cells grow and divide. Every minute my body makes more than a
billion new cells. Cells make new cells by growing and splitting in two.
In order to live, cells need food and oxygen. Oxygen is in the air. I
breathe air. I eat food. My body changes these a little bit, and then my
blood is able to carry them to all the cells in my body.
My cells use up the food and oxygen and give off things cells cannot
use. The useless things are called waste products. My blood carries
waste products away from my cells.
Cells do special jobs. I have skin cells, bone cells, blood cells, brain
cells. All together, billions of cells make up the body of the person I
call “Me.”
Some of the cells in my body are bigger than others. But all are tiny.
About 6 million skin cells would fit into the empty square.
\| Inside and Outside of Me
