The periodic table of the elements with the most common elements within living cells highlighted.
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L.Gardiner/Windows to the Universe

The Elements of Life

Elements make up everything around us including the trees of a forest, your pets, and even YOU!

If you looked at living things with a microscope, you would see that all life is made up of small compartments called cells. Very small life forms, such as bacteria, have only one cell, while large animals have millions. No matter what type of living thing, the cells of every creature are made of atoms of different elements.

The most common elements in a cell are:
Hydrogen (H) 59%
Oxygen (O) 24%
Carbon (C) 11%
Nitrogen (N) 4%
Others such as phosphorus (P) and sulphur (S) 2% combined

But these are not the only elements that have important roles for living things! Plants and animals need a variety of elements to survive and grow.

Some elements that are important for animals (including people) are calcium (Ca), for bones and muscles, chlorine (Cl) for digesting food, fluorine (F) for tooth enamel and iron (Fe) to help blood carry oxygen around the body.

Plants also need elements to survive and grow including magnesium (Mg) and chlorine (Cl) that help plants convert the Sunís energy into food. Some plants, such as grass, contain silica (Si), which makes them very strong.

Last modified July 7, 2004 by Lisa Gardiner.

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