Chapter 5 - Enzymes

BIOLOGICAL CATALYSTS

• catalyst= a substance that increases the rate of a chemical reaction and is not changed by the reaction. 
• enzymes= proteins that function as biologcal catalysts. 
• Chemical reactions are sometimes called metabolic reactions. Almost every metabolic reaction is controlled by catalysts called enzymes.
• Starch is digested to the sugar maltose by an enzyme calld amylase.
• Protein is digested to amino acids by protease. 
• Catalase is another enzyme which speeds up the breakdown of a substance. It breaks down hydrogen peroxide to water and oxygen. 
• Not all enzymes help break things down; many enzymes help to make large molecules from small ones. 

• carbohydrases= enzymes which catalyse the breakdown of carbohydrates. 
• proteases= enzymes which catalyse the breakdown of proteases. 
• lipases= enzymes which catalyse the breakdown of fats (lipids).

• The carbohydrase that breaks down starch is called amylase.
• The carbohyrase that breaks down maltose is called maltase.
• The carbohydrase that breaks down sucrose is sucrase. 

• The lock and key mechanism is when a substrate molecule fits perfectly into an enzyme.

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