enzymes

• catalyst — substance that can speed up chemical reactions without itself being chemically changed at the end of the reaction
• 1. enzymes are (generally) protein in nature
• 2. enzymes are biological catalysts which increase the speed of chemical reactions
• 3. enzymes are complementary to the substrate
• 4. enzymes remain chemically unchanged at the end of the reaction
• 5. only minute amounts of enzymes are required to catalyze a large number of reactions
• enzymes are biological catalysts that can alter or speed up chemical reactions. they are proteins and remain chemically unchanged at the end of the reaction
• 6. enzymes lower the activation energy required for a reaction to proceed
• 7. enzymes are temperature sensitive and work best at optimum temperature
• 8. enzymes are pH sensitive and work best at optimum pH
• 9. enzymes catalyze reversible reactions
• anabolic reactions — building up of complex substances

  eg joining amino acids together during protein synthesis
• catabolic reactions — breaking down of complex substances

  eg breakdown of glucose during respiration