What is glucose or blood sugar?

  • Cells get the energy they need from glucose during respiration.

  • Glucose is made by digesting carbohydrates.

  • Blood sugar level is the amount of glucose in one litre of blood.

A case study video explaining what role glucose plays in the body.

Why is glucose important?

You need energy for everything you do. Your cells get this energy from chemical reactions of glucose.

Glucose is a molecule with the chemical formula, C₆H₁₂O₆. A molecule of glucose contains carbon, hydrogen and oxygen atoms.

A model of the atoms found in a molecule of glucose.

Sources of glucose

Foods like bread, pasta and rice contain carbohydrates, which are your main source of energy. Digestion breaks down these carbohydrates, making glucose.

Many sweet foods, and energy drinks, already contain glucose. They make you feel energetic straight away.

Blood sugar

The amount of glucose in one litre of blood is called your blood sugar level. In most people, the body controls this level effectively at around 1 gram of glucose per litre. However, in people with diabetes, the body does not control blood sugar levels properly. Levels that are too high or too low cause serious health problems.