enzymes

• Enzymes are...

  catalysts produced by living things
• Chemical reactions in living things need to be..

  carefully controlled to get the correct amount of substances
• You can make a reaction happen quicker by..

  raising temperature

  using enzymes
• Enzymes are biological catalysts
• There is a limit to how high you can increase temperature before cells start to become damaged.
• A catalyst is a substance which increases the speed of a reaction without being used up or changed in the reaction.
• Enzymes reduce the need for high temperatures so we only use enzymes for chemical reactions in the body.
• Enzymes are all large..

  proteins
• Enzymes are all large proteins which are made up of chains of amino acids.
• What are enzymes made up of?


  they are large proteins made up of chains of amino acids
• Enzymes have special shapes so they can catalyse reactions.
• Chemical reaction normally involve things either being split apart or joined together.
• Every enzyme has an active site which fits a substrate.
• If a substrate doesn't fit into the enzymes active site, the reaction won't be catalysed.
• Enzymes usually only catalyse one specific reaction.
• Name the model commonly associated with enzymes.

  lock and key
• In a reaction, the active site of the enzyme changes shape a little as the substrate binds to get a tighter fit.
• What is the model called where the active site changes slightly as the substrate fits?


  Induced fit model
• Enzymes need the right temperature and pH.
• Changing temperature changes the rate of an enzyme-catalysed reaction.
• A higher temperature increases the rate of a reaction.
• If temperature is too high, bonds holding the enzyme together will break and change the shape of the active site. (denaturing)
• What is it called when the active site changes shape and can no longer fit the substrate?

  denaturing
• pH affects enzymes.
• Too high or too low pH can interfere with the bonds holding the active site together and denature the enzyme.
• All enzymes have an optimum pH.
• Enzymes often work at neutral pH 7. (not always)
• What enzyme works at pH 2?

  pepsin
• What is pepsin?

  An enzyme used to break down proteins in the stomach.
• Digestive enzymes break down big molecules.
• Starch, proteins and fats are big molecules.
• Starch, protein and fats are too big to what?

  pass through the walls of the digestive system
• Digestive enzymes break down starch, proteins and fats.
• The smaller the molecules the more easily they can pass through the walls of the digestive system allowing them to be absorbed into the bloodstream.
• Carbohydrases convert cabrohydrates into what?

  simple sugars
• What does carbohydrase convert into simple sugars?

  carbohydrates
• Name the common carbohydrase found in the digestive system.

  Amylase
• What does amylase break starch down into?

  maltose and other sugars
• Where is amylase found?

  salivary glands

  pancreas

  small intestine
• Starch is a..

  carbohydrate