The Role Of Enzymes In Living Organisms

Chemical reactions can occur at a quicker rate as a result of using substances called catalysts. A catalyst is a substance which increases the rate of the chemical reaction without being affected and as a result they can be recovered – being chemically unchanged at the end of the reaction. This process is known as catalysis. Enzymes are described as any part of a group of complex proteins or conjugated proteins that are produced by living cells and act as biological catalysts in specific chemical reactions. Enzymes are one the most powerful catalysts and play an important role in living organisms as they allow reactions which would normally require extreme temperatures to occur in all living cells without destroying the organic matter. For a chemical reaction to occur a minimum threshold must be exceeded for a process to occur. This is the activation energy. Enzymes catalyse reactions by lowering the activation energy of a chemical reaction which allows the reaction to happen at lower temperatures.

Enzymes are proteins and have a specific shape for its specific function. The structure and therefore role of the enzyme is determined by its primary, secondary, tertiary and quaternary structure and these are depicted below:

The rate increases with temperature up to the optimum temperature. The rate increases because the enzyme and substrate molecules both have more kinetic energy so collide more often and also because more molecules have sufficient energy to overcome the activation energy. Above the optimum temperature there the hydrogen bonds holding the tertiary structure of the enzyme together break, so the active site loses its specific shape and subsequently, the substrate is not complementary to the active site and cannot form an enzyme-substrate complex so the reaction cannot be