ENZYMES

There are thousands of reactions that occur within organisms. These reactions would occur very slowly or not at all without enzymes.

Reactions can: Build new molecules Break down molecules ++ Enzymes speed up theses chemical reactions. Enzymes are catalysts.

How do enzymes speed up reactions? Enzymes lower the activation energy

enzyme substrate product active site Enzymes are not changed by the reaction. Lock & Key: Specific substrate attaches to specific enzyme

How well an enzyme works depends on: pH ( acids & bases) Temperature

37° temperature reaction rate Human enzymes Temperature and Activity of Enzyme The activity of the enzyme decreases at temperatures above and below the optimum temperature.

7 pH reaction rate Stomach pepsin Intestine trypsin Each enzyme works best at a specific pH. Optimum pH = 3Optimum pH = 8 pH and Activity of Enzyme

7 pH reaction rate Stomach pepsin Intestine trypsin The activity of the enzyme decreases at pH above and below the optimum temperature.

Acid Base pH Scale