Enzymes - biological catalysts that control the reactions of life. Inside every cell hundreds of chemical reactions take place. Enzymes help control the rate of all these reactions and make sure that they take place at the right place and in the right order for the cell to survive. This online resource explores questions such as: How do the right chemicals react together in your cells? Why do reactions take place so fast inside a cell? Why is it so dangerous if you have a fever that goes over 40°C? How can organisms survive in hot springs at temperatures above the boiling point of water? This resource follows on from the 14-16 resource, Enzymes and their uses.