The basic unit from which all living organisms are built up, consisting of a cell membrane surrounding cytoplasm and a nucleus.
The organ system in the body which breaks down large insoluble food molecules into small soluble molecules which can be used by the body
Breaking down glucose (food) without oxygen to provide available energy for the cells. The glucose reacts with oxygen to produce energy in the form of ATP with carbon dioxide and water as waste products
A polymer made up of amino acids joined by peptide bonds. The amino acids present and the order in which they occur vary from one protein to another.
Reusable protein molecules which act as biological catalysts, changing the rate of chemical reactions in the body without being affected themselves
Enzymes are biological catalysts that speed up chemical reactions in living organisms. There are more than five hundred different enzymes in every cell of the body, each of them helping the cell, and the body as a whole, to work.
Some enzymes work outside the cells, for example the enzymes in the digestive system.
Enzymes are involved in all biological reactions, e.g. cellular respiration, photosynthesis and protein synthesis. Without enzymes these vital reactions would be too slow for life to continue.