Enzymes

• Enzymes


  Biological catalysts that control reactions in the body
• Enzymes


  • They catalyse reactions that synthesise large molecules from smaller ones
  • They catalyse reactions that break down large molecules into smaller ones
• Enzymes as catalysts


  • They speed up the rate of a chemical reaction but are not used up in the reaction
  • This means they can be used over and over again
• Enzymes


  • amylase
  • lipase
  • protease
• Digestion


  Large food molecules are broken down so that they can be absorbed into the blood
• Synthesis


  1. Larger molecules are synthesised from smaller molecules

  2. This is important inside cells for supporting life processes and growth
• Molecules enzymes work with

  • carbohydrates
  • proteins
  • lipids
• Enzymes digest large molecules


  Into smaller molecules
• Enzymes synthesise larger molecules


  From smaller molecules
• Enzymes are not used up in the reactions they catalyse</b>
• Enzymes can be used over and over again
• Enzymes speed up the rate of chemical reactions
• Enzymes catalyse reactions that synthesise large molecules from smaller ones
• Enzymes catalyse reactions that break down large molecules into smaller ones
• Enzymes


  • They are proteins
  • They function as biological catalysts
  • They speed up a chemical reaction without being changed
• Active site


  Where the substrate molecule fits in
• Lock-and-key shape


  The shape of the active site is complementary to the substrate molecule, making enzymes highly specific
• Each type of enzyme can usually catalyse only one type of reaction
• Enzyme catalysis


  1. Substrate collides with active site

  2. Substrate becomes attached

  3. Catalysis

  4. Enzyme remains unchanged and can be reused

  5. Products released from active site
• As temperature increases


  Rate of reaction increases
• At high temperatures


  The enzyme denatures and the rate of reaction decreases
• Optimum pH


  Each enzyme works best at a specific pH value, which depends on where it normally works
• As pH increases


  Rate of reaction increases
• Continued pH increases


  Cause the enzyme to denature and the rate of reaction decreases sharply
• Substrate concentration


  • As substrate concentration increases, rate of reaction increases
  • Rate doesn't increase forever as enzymes become saturated and no more substrate can fit in at any time
• Carbohydrates


  • Carbohydrase enzymes break down disaccharides and polysaccharides into simple sugars
  • Produced in saliva, pancreas, and small intestine
• Proteins


  • Large molecules made from amino acids joined together in chains
  • Include enzymes, haemoglobin, collagen, keratin
  • Protease enzymes break down proteins into amino acids, which can then be joined together for growth and repair
  • Produced in stomach, pancreas, and small intestine
• Lipids


  • Large molecules made from fatty acids and glycerol
  • Lipase enzymes break down lipids in the diet into fatty acids and glycerol
  • Produced in pancreas and small intestine