Digestion Topic Flashcards
Test for starch
Add iodine to starch
Iodine is originally brown
Then it should be blue black
Test for sugar
Add Benedicts solution to sugar
Benedicts is originally blue
Then it should be brick red
Test for protein
Add Buiret solution to protein
Buiret solution is usually colourless
Then it should be lilac
Test for fat (lipid)
Add ethanol and water to fat
Ethanol and water is usually colourless
Then it should be white emulsion
Vitamins
They keep you healthy
Found in vegetables and fruit
Minerals
They help your body work healthily
Found in a bit of everything (in a balanced diet)
Fibre
To keep the digestive system working properly
Found in whole meal breads, cereal, fruit + veg
Fats
For vitamins to dissolve + for fat to protect organs
Found in vegetables fats: soya, sunflower, olive oil
OR
Milk, butter, pork, egg
Protein
Needed for growth of muscles and repair of cells (eg. Skin)
Found in fish + poultry, grains + pulses, peas + beans
Carbohydrates
Main source of energy
Found in starch (bread, rice, pasta)
AND sugars (cake, jam)
Water
Keeps us alive, allows chemical reactions to take place. 70% of our body is made up of water.
Most foods contain water (eg watermelon) but you could just drink water
Label a tooth
Top - enamel Dentin Pulp cavity Crown Gum Jaw bone Root Nerves and blood vessels Bottom -
Incisor
Flat
Bites off parts of food
Canine
Sharp and pointy
Rips food apart
Pre molar
Nearly a molar - smaller version
Grinds food
Molar
Wide
Grinds food and chewing
Parts of digestive system
Saliva glands To the oesophagus To the liver To the stomach To the pancreas To the small intestine To the large intestine To the anus
Saliva glands
Where saliva is made
Oesophagus
Moves food from mouth to stomach
Liver
Produces bile (an alkaline fluid that aids digestion) and detoxifies stomach acid
Stomach
Holds food and starts to break it down using a strong acid
Pancreas
Produces enzymes that work in the small intestine
Small intestine
Extracts nutrients + absorbs them into the booodstream
Large intestine
Absorbs water from undigested food leaving faeces
How can we break down our food?
We can either break it down mechanically or chemically.
How do you break down food mechanically?
By chewing it on the mouth and churning it in the stomach
How do you break down food chemically?
By adding enzymes
What are enzymes?
Enzymes are proteins that act as catalysts (chemicals that don’t take part in a reaction but speed it up)
They break down nutrients into building blocks which are then rebuilt into other things.
e.g. amino acids combine to create hair, skin, enzymes. Certain combination make certain things.
Explain in greater detail the process of digestion
First there is churning in the stomach.
Then the food is chemically broken down in the stomach, pancreas and the small intestine.
The liver makes bile which is alkaline and so neutralises the acidic food as it comes out of the stomach.
Then comes the small intestine where the small nutrients are dissolved into the bloodstream.
Most of the water is absorbed by the large intestine.
Any undigested food is stored in the large intestine until it is ready to leave through the anus as faeces which is mainly fibre.
Why do we need to digest?
We need to digest food to break down large insoluble molecules into smaller molecules, which can be absorbed into the bloodstream
Protease
Protease - breaks down protein into amino acids
Stomach, pancreas, small intestine
Amylase
Amylase - breaks down starch into maltose.
Salivary glands, pancreas
Lipase
Lipase - breaks down fat into fatty acids and glycerol
Pancreas, small intestine.
Does Saliva contain amylase enzyme?
Yes, when you test starch with saliva, the colour (with the iodine added) is white and yellow
Can boiled saliva break down starch?
No, boiled enzymes don’t break down starch because the molecules in the enzyme change shape therefore they won’t fit -they’ve become denatured.
