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1. 09/23/15
Food and DigestionFood and Digestion

2. 09/23/15
Food typesFood types
TypeType Found inFound in UsesUses
Carbohydrates
Fats
Proteins
Vitamins
Minerals
Fibre
Water
Bread, potatoes, cereal
Cream, butter, milk, oil
Meat, fish, eggs
Vegetables, cereal
Meat, milk, cereal
Fruit + veg, cereal
Water!
Energy
A store of energy
Building and repairing cells
Keep things “ticking over”
Strong teeth etc
75% of the body is water
Keeps you regular!

3. 09/23/15
Food tests 1Food tests 1
To investigate what happens in digestion we need to be able
to test for different foods. Here are two simple tests:
1) The test for starch:
Drop some iodine onto the food. If
the iodine turns BLUE/BLACK then
STARCH is present.
2) The test for simple sugars (e..g
glucose)
Boil the food with some Benedict’s
solution. If an orange
“precipitate” appears then the
food contains simple sugars
Iodine

4. 09/23/15
Food tests 2Food tests 2
1) The test for protein:
Add 5cm3 of dilute sodium hydroxide
followed by 5cm3 of dilute copper
sulphate. If protein is present it
will produce a purple colour.
2) The test for fats:
Shake the food with about 10cm3 of
ethanol in a test tube. Pour some
of the solution into a tube
containing water. If fat is
present the water will turn
cloudy white.

5. 09/23/15
The digestive systemThe digestive system
The whole point of digestion is to break down our food so
that we can get the bits we need from it…
The main foods
affected are
CARBOHYDRATES –
these are broken down
into GLUCOSE

6. 09/23/15
EnzymesEnzymes
Enzymes are chemicals produced by the body to help
_______. When they react with food they break it down
into ______ pieces which can then pass into the ______:
Carbohydrase breaks _______ (a
carbohydrate) down into glucose:
Protease breaks _______ down
into amino acids:
Lipase breaks fats (_____) down
into fatty acids and glycerol:
Words – blood, lipids, proteins, digestion, starch, smaller

7. 09/23/15
The small intestineThe small intestine
This is where the “small parts” are absorbed into our blood
stream…
Glucose gets
absorbed into
the blood
Everything else
passes into the
large intestine