1. The essential key to the functioning of all cells

2. Enzymes - Are Proteins Act as Organic Catalysts, which speed up the rate of chemical reactions Control a wide variety of reactions with cells Example: Photosynthesis and respiration are both controlled by enzyme reactions

3. There are 2 groups of enzymes: Intracellular enzymes: inside cells  speed up & control metabolic reactions; Extracellular enzymes: outside cells  include digestive enzymes which break down food

4. The Role of Enzymes - Enzymes are very specific Each enzyme only acts on one Substrate ( the compound being acted on by the enzymes) This is due to the shape of an enzyme matches a particular substrate Http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/a nimation__how_enzymes_work.html

5. Enzymes Activity Enzyme Activity can be influenced by their surroundings which include – Temperature – High temperatures ( Over 40 degrees Celsius) tend to denature the enzymes permanently, at low temperatures slow down reactions, but no permanent damage is done.

6. pH Levels – Most of the time optimum activity is when there is a pH of 7, depending on the area the reaction is occurring. As in the stomach the pH is 2 and enzymes play a vital role in breaking down food. Enzymes can also be influenced by the concentration of the particular enzyme as well as the concentration of the substrate ( the substance the enzymes is acting on)

7. Enzymes are denatured beyond 40 O C Enzymes Yeast is an example of an enzyme. It is used to help a process called fermentation: Sugar Alcohol + carbon dioxide The alcohol from this process is used in making drinks and the carbon dioxide can be used to make bread rise. Enzymes work best in certain conditions: Enzyme activity TemppH 40 0 C Could be protease (found in the stomach) Could be amylase (found in the intestine)

8. Denaturation Proteins change shape when the temperature or pH reaches levels outside of the optimal range & if bonds between amino acids are broken, the protein is destroyed.

9. Uses of enzymes 1) Enzymes are used in washing powders to help digest food stains. Biological washing powders will only work on 40 0 C or lower. 2) Enzymes are used in baby foods to “pre-digest” the proteins. 3) Enzymes are used to convert starch into sugar which can then be used in food. 4) Conversion of glucose into fructose – glucose and fructose are “isomers” (they have the same chemical formula), but fructose is sweeter.