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• Cellulose is the main substance found in plant cell walls and helps the plant to remain stiff and strong.
• Humans cannot digest cellulose, but it is important in the diet as a source of fibre.
• Cellulose is used to make clothes and paper.

Cellulose is a molecule, consisting of hundreds – and sometimes even thousands – of carbon, hydrogen and oxygen atoms. Cellulose is the main substance in the walls of plant cells, helping plants to remain stiff and upright.

Humans cannot digest cellulose, but it is important in the diet as fibre. Fibre assists your digestive system – keeping food moving through the gut and pushing waste out of the body.

Animals, such as cows, sheep and horses, can digest cellulose, which is why they can get the energy and nutrients they need from grass.

Cellulose has many uses. In cotton, it makes clothes like t-shirts and jeans. Paper-making needs huge quantities of cellulose, obtained mainly from wood.

Cellulose is an example of a natural polymer. A polymer is a long and repeating chain of the same molecule stuck together.

Cellulose is a long-chain polymer of glucose molecules joined together. As the plant adds one glucose molecule to the polymer, one molecule of water is released. You can see this mechanism in the video opposite. Cellulose polymerisation occurs as a plant grows and creates new cells.