DATE: 25TH January, 2011.
FORM CLASS: L6 3
SUBJECT: Biology
TITLE: Enzymes
AIM: To investigate the effect of temperature on the enzyme lipase
INTRODUCTION:
The phenomenon of catalysis makes possible biochemical reactions necessary for all life processes. Catalysis is defined as the acceleration of a chemical reaction by some substance which itself undergoes no permanent chemical change. The catalysts of biochemical reactions are enzymes and are responsible for bringing about almost all of the chemical reactions in living organisms. Without enzymes, these reactions take place at a rate far too slow for the pace of metabolism.
Enzymes are globular proteins which catalyse and regulate chemical reactions in all living organisms. Since they are not used up in reactions (but warn down), enzymes can be used over and over again. Enzymes posses an active site; which only recognizes a particular substrate. The shape of this site allows for a particular enzyme to bond with its substrate to form a temporary enzyme-substrate complex. The specificity is referred to as “the lock and key theory”, but in practice works more like a “hand and glove fit”. Once the reaction has occurred, the product(s) break free of the enzyme, leaving it free to catalyse more reactions.
Enzymes lower the amount of energy necessary to make reactions occur, by lowering the activation energy of that particular reaction. There many factors that affect the rate of enzyme catalysed reactions such as; temperature, the enzyme becomes thermodynamically denatured, pH some enzymes are pH specific, and concentration of the substrate or enzyme.
As stated above enzymes are globular proteins. They are held into shape by weak hydrogen bonds. If the temperature is increased to high, there is sufficient energy to break the hydrogen bonds. If the hydrogen bonds are broken the globular proteins unravel, and the enzyme loses its shape. Since shape is essential to its ability to catalyse, enzymes, base on