enzymes

• enzymes are protiens that are catalysts that speed up chemical reactions in living things
• enzymes are all large proteins that are made up of chains of amino acids
• enzymes have special shapes so they can catalyse reactions . chemical reactions usually involve things being split up or joined together
• every enzymes has an active site with a unique shape that fits in a specific substrate involved in the reaction
• substrates are molecules that react with enzymes
• enzymes need the right temperature and pH to work properly.
• higher temp = increase rate of enzyme-catalyst reaction
• but if temp is too hot, some of the bonds holding enzymes together break and the enzymes denature because the shape active site so the substrate wont fit
• all enzymes have a optimum temp where they work best
• the pH also affects the enzyme. if its too high or low it interferes with the bond holding the enzymes together . this changes the shape of active site and denatures the enzyme
• all enzymes have a optimum pH that they work best if often 7 (neutral) but not always
• enzymes used in digestion break down big molecules
• starch, proteins and fats are big molecules that are too big to pass through the walls of digestion system so digestive enzymes break them down into smaller molecules like sugars, amino acids, glycerol and fatty acids. they can now pass through the walls of the digestive system and into bloodstream
• carbohydrase convert carbohydrates into simple sugars . amylase are an example of carbohydrase that break down starch . amylase are made in the salivary glands and pancreas
• proteases convert proteins into amino acids. proteases are found in the stomach, small intestine, pancreas
• lipases convert lipids into fatty acids and glycerol. lipases are found in the pancreas and small intestine
• bile neutralises the stomach acid and emulsifies fats
• bile is produced in the liver and stored in the gall bladder then realised into small intestine . the hydrochloric acid makes the pH too acidic for enzymes to work properly - bile (an alkaline) neutralises it and makes conditions alkaliane for enzymes to work properly
• it emulsifies fats - breaks down fat into smaller pieces so its a bigger SA for the enzymes lipase to work , which makes digestion faster
• the breakdown of food is catalysed by enzymes, which in the digestive system are produced by specialised cells in glands and gut linings
• salivary glands - these produces amylase enzymes in the saliva

  (starch)
• stomach- 1)produces hydrochloric acid to kill bacteria and digest food, and give right pH for protese enzymes to work(protiens-amino acids)
• stomach- 2)it pummels the food into a paste with its muscular walls
• liver - where bile is produced, bile neutralises stomach acid and emulsifies fat
• gall blander - where bile is stored, before being releases into small intestines
• pancreas - produces protease, amylase and lipase enzymes it releases them into small intestine
• small intestines- produces protease, amylase and lipase enzymes to complete digestion
• small intestine- absorbs nutrients from food out the digestive system into the blood stream
• large intestine - absorbs water and electrolytes from undigested food
• rectum - stores faeces and waste products from the small intestine