Enzymes

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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 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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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 anus

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