Properties of Enzymes Describes what they are, how they work etc... This presentation belongs to my Biology Teacher, I found this helpful and thought might help others.. so no copyright intended.

1. Enzymes

2. Enzymes Enzymes Made of protein Present in all living cells Converts substrates into products Biological catalysts Increase the rate of chemical reactions Remain unchanged by chemical reaction

3. Product Chemical Reactions A chemical reaction happens when one or more substances is chemically changed into one or more different substances. A + B C + D Chemical reactions take place in cells all the time. These are metabolic reactions. Now some reactions are so slow that they need an enzyme or catalyst to speed them up. Enzyme Catalase Water + oxygen Catalyst Example Most metabolic reactions are reversible, this means they can go in either direction. A + B C + D Substrate Hydrogen peroxide

7. There are thousands of different enzymes in your body. Why are there so many different enzymes? One Enzyme – One Reaction Each enzyme has its own unique protein structure and shape called its ACTIVE SITE, which is designed to match or COMPLEMENT its substrate.

11. Lock & Key Hypothesis An enzyme only acts on one type of substance, or substrate. Therefore, the enzyme is said to be SPECIFIC to its one substrate. The shape of the active site (binding site) of the enzyme, matches the shape of the substrate. Allowing the two molecules to bind during the chemical reaction. This theory of enzyme action is called the ‘lock-and-key’ hypothesis.

14. Effect of Temperature What happens to the activity of an enzyme as the temperature changes?

15. Movie Effect of pH on enzymes When the pH changes beyond the optimal conditions, the shape of the active site of the enzyme alters and the enzyme is denatured.

16. Most enzymes work best at a pH close to neutral (pH7), but there are some exceptions. Pepsin, an enzyme found in the stomach, has an optimum pH of 2. Pepsin Catalase Trypsin Effect of pH on enzyme activity