Fermentation - GCSE Biology Definition

Fermentation is a process used by cells to produce energy without needing oxygen. It often involves turning sugars into other substances, like alcohol and carbon dioxide. For example, yeast cells perform fermentation to make bread rise and to produce alcohol in drinks. In your body, a type of fermentation happens in your muscles during hard exercise, creating lactic acid, which can cause cramps. This process is important in biology because it helps cells survive and make energy when there's little or no oxygen available.