Enzymes

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Enzymes

  • Enzymes are catalysts produced by living things
    • living things have lots of different chemical reactions going on inside, and need to be carefully controlled to get the right amount of substances
    • by making the reaction happen more quickly, raise the temperature which speeds up all sorts of reactions, the good and bad
    • there is a limit to how high the temperature can be increased before they are damaged and denatured
    • living things produce enzymes that act as a biological catalyst, they reduce the need for high temperatures and only have enzymes to speed up the useful chemical reactions
    • a cataylst is a substance which inceases the speed of a reaction, without being changed or used up in the reaction
    • enzymes are all proteins --> which are made of chains of amino acids --> folded into unique shapes to enable them to do their job
    • proteins act as structural components of tissues, hormones and antibodies
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Enzymes

  • Enzymes have special shapes so they can cataylse reactions 
  • chemical reactions involve things being split apart or joined together 
  • every enzyme has a unique shape that fits onto the substance in the reaction and only cataylse one reaction 
  • for it to work, the substance has to fit into the special shape and if the substance doesnt match the shape, the reaction won't be cataylsed
  • enzyme, substance --- enzyme+substance together ---- substance splits after reaction
  • Enzymes need the right temperature and pH 
  • it reaches the optimum temperature, where the enzyme is most active, if it gets too hot, the bonds holding the enzyme together break, so the substance cant fit into the special shape meaning it doesn't work anymore and the enzyme denatures
  • the pH interferes with the bonds holding the enzyme together if the pH is too high or low - changes the shape and the enzyme is denatured
  • all enzymes have an optimum pH, what they work best at which is usually pH 7, not always
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Enzymes and Digestion

  • Digestive Enzymes break down bigger molecules into smaller molecules
  • Starch, proteins and fats - too big to pass through the walls of the digestive system
  • Sugars, amino acids, glycerol and fatty acids - pass easily through walls of digestive system
  • enzymes end in "ase"
  •  
    • AMYLASE = cataylses the breakdown of starch molecules into sugar molecules, amylase is made in the salivary glands, pancreas and small intestine
    • PROTEASE = catalyses the breakdown of protein molecules into amino acids, protease is made in the stomach, pancreas and small intestine
    • LIPASE = catalyses the breadown of fat molecules (lipids) into fatty acids and glycerol molecules, lipase is made in the pancreas and small intestine
    • Bile neutralises the stomach and emulsifies fat (turns lumps of fat into fatty droplets) - produced in the liver and stored in the gall bladder before being released in the small intestine. hydrochloric acid in stomach makes pH too acidic for enzymes to work properly. It is an alkaline and neutralises the acid. 
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Breakdown of Food

  • Breakdown of food is cataylsed by enzymes..enzymes in the digestive system are produced by specialised cells in glands and gut lining. Different enzymes cayalyse the breakdown of different food molecules. 
  • Salivary Glands:
  • produce amylase enzyme in saliva
  • Liver:
  • bile is produced, bile neutralises the stomach acid and emulsifies fats
  • Gall Bladder:
  • bile is stored before released into small intestine
  • Large Intestine:
  • excess water is absorbed from food
  • Stomach:
  • pummels the food with muscular walls
  • produces protease enzyme (pepsin)
  • produces hydrochloric acid: to kill bacteria, and to give the right pH for the protease enzyme to work as pH 2 is acidic
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Breakdown of Food

  • Pancreas
    • produces protease, amylase and lipase enzymes
    • releases these into the small intestine
  • Small Intestine:
    • produces protease, amylase and lipase enzymes to complete digestion
    • digested food is absorbed out of the digestive system into the blood
  • Rectum:
    • faeces (indigestable food) are stored before leaving the ****
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