Enzymes and digestion: Organisation: Biology: GCSE (9:1)

• Enzyme

  Biological catalysts which speed up reactions without being used up

  
• Enzymes and temperature

  The enzyme rate increases as temperature increases up to an optimum, after which the enzyme becomes denatured

  
• Enzymes and pH

  The reaction rate decreases as the pH moves away from the enzyme's optimum pH

  
• Denature


  When the active site changes shape and can no longer bind to a substrate due to unsuitable temperature or pH

  
• Active site

  The part of an enzyme where the substrate binds

  
• Substrate

  Reactant of an enzyme catalysed reaction

  
• Product

  A substance produced in a chemical reaction

  
• Lock and key theory

  When a substrate fits into its enzyme just like a key fits a lock

  
• Amylase


  A carbohydrase enzyme found in saliva and the small intestine that breaks the chemical bonds in starches

  
• Protease


  Enzyme found in the stomach and small intestine that breaks down proteins into amino acids

  
• Lipase


  Enzyme found in the small intestine that breaks down lipids into glycerol and fatty acids

  
• Carbohydrases

  Enzymes that speed up the breakdown of carbohydrates into simple sugars

  
• Proteins

  Building blocks of cells and tissues

  
• Carbohydrates


  Provide energy for chemical reactions

  
• Lipids


  Fats and oils which store energy