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How do plants make sugars?

All green plants make sugars. They take up water and minerals from the soil through their roots and carbon dioxide through their leaves. Leaves contain a green substance called chlorophyll (this gives plants their characteristic colour). The chlorophyll uses light energy from the sun to combine carbon dioxide and water to produce sugar. The by-product of this process is oxygen.

The family of sugars

There are a whole range of substances which make up the family of sugars. These include the sugars made by plants during photosynthesis, milk sugar and honey.

Our bodies use all sugars in basically the same way, whatever the source, to give us energy for life.

Sugars - the building blocks for plants

The sugars produced by photosynthesis provide an immediate source of energy for plants to live and grow. Excess sugars can be stored as sucrose. This provides an energy reserve at night, when plants cannot photosynthesise.

Sugars are also used as building blocks for making all the other substances which plants need for growth and repair. For example, sugars can be used to make complex substances (dietary fibre) which form plant cell walls and provide the plant with structure and support.

Glucose can be used by plants to make starch which is made up of long, branched chains of glucose. Starch is found in large quantities in potatoes, rice and cereal grains (eg wheat).

For further information please visit British Sugar plc, SilverSpoon and Tate and Lyle

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