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Enzymes are biological catalysts. They speed-up chemical
reactions in your body. There are two kinds of enzymes in our bodies:
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Intracellular enzymes are found inside cells. |
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Extracellular enzymes are found outside cells. |
Don't worry too much about that, but you might like to know a little more about the
enzymes in your intestines. I hope that you have already looked at my pages on the digestive system and a balanced diet.
Some people say that there is food going round their bodies in their blood, but they
are not very accurate. You cannot have chips, strawberries, pies and fanta in your blood
vessels: even sardines and beans are just too big. Large lumps of food havve to be chewed
up into smaller pieces which can be swallowed. Then your food has to be digested. The
molecules of carbohydrates, proteins and fats are too big to get into your blood.
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All the carbohydrate in your food is turned into a sugar called glucose, |
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The protein is turned into amino-acids, |
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Fats are turned into fatty acids and glycerol. |
Vitamins and mineral salts are already small enough to get into your blood without
being digested.
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Starch is digested by an enzyme called "amylase" |
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Lactose (the sugar in milk) is digested by lactase, |
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Sucrose (the sugar you put on cornflakes) is digested by sucrase, |
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Proteins are digested by enzymes called proteases, e.g. pepsin, |
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Fats are digested by lipase. |
Enzymes need special conditions to work properly:
- They must have the correct pH (pH 1 to 6 is acid, pH 7 is neutral, and pH 8 to 14 is
alkaline),
- They must have the correct temperature (for us this is 36.5 degrees C),
- They only work on one kind of food (pepsin will only digest protein),
- They are poisoned by some metal ions.
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