human nutrition: balanced diet Flashcards
what are carbohydrates made up of
are made up of simple sugars
—-> involves the elements hydrogen, oxygen and carbon
what are proteins made up of
Are made up of amino acids
lipids are made from
Fatty acids and glycerol
glucose food test
Benedict’s solution
Benedict’s solution is normally …..
Blue
In high concentrations of glucose the food test will turn
- food test —> Benedict’s solution
- turns BRICK RED in high concentrations
In low concentrations Benedict’s solution (GLUCOSE) will turn…
Green or yellow
To test for starch
Iodine solution
Positive test for iodine solution
Blue-black
Original colour of iodine solution (STARCH)
browny-orange
To test for proteins…
Use the biuret test
Containing proteins the solution will change from
Blue—>pink—>purple
To test for lipids use the
Sudan III test or the emulsion test
what do carbohydrates do
provide energy
lipids/fats do…
provide energy and act as insulation and as a energy store
proteins do…
are needed for growth and repair of tissue and to provide energy in emergencies
Vitamin A
- improves vision
Vitamin C
Is needed to prevent scurvy
Vitamin D
- helps calcium absorbtion
eggs provide
Vitamin D
(Think sunny side up because you can get vitamin d from sunlight and eggs)
liver has high levels in of
vitamin a
Lipids are found in
Butter and oily fish
Purpose of water
- needed in cellular reactions
Iron (a mineral iron)
Makes haemoglobin
Calcium (a mineral ion)
Needed to make bones and teeth
Fibre
Aids the movement of food through the gut
Dietary fibreis found in
Is found in wholemeal bread and fruit
Peristalsis
The movement of food through the gut using circular muscle contractions
Amylase converts starch into
Maltose
—-> converted by maltase
—-> into glucose
STARCH—->MALTOSE—->GLUCOSE
amylase
maltase
Proteins—-> amino acids
Proteases
Lipids are converted by lipases into
Glycerol and fatty acids
Bile is produced in the
Liver
What is the functions of bile?
- neutralises HCl in the stomach so it will not denature the enzymes in the small intestine that work in alkaline conditions
- emulsified fats - making the surface area bigger for lipase to work on so digestion is faster
A….. C….
Alimentary canal
Salivary glands produce
Amylase
—-> chemical digestion
The gall bladder stores
Bile
Rectum stores
Faeces
Villi are in the
Small intestine
The function of the small intestine is
- produces lipases, proteases and amylase
- nutrients are absorbed out of the alimentary canal into the body
- duodenum - first part
- ileum - second part
Large intestine:
Excess water is absorbed from food
The villi is adapted to it function because
- really big surface area - millions and millions of villi
- each cell on the villi also has MICROVILLI
–> SA increased even more - villi have a single layer of cells which are very permeable
- a very good blood supple
—> fast absorption
Describe and name the test for proteins:
BIURET SOLUTION: PROTEIN
- the solution will change from BLUE to PINK or PURPLE
- use a 2cm^3 sample of food and place it into a test tube
- add 2cm^3 of biuret solution
- gently shake it
no special conditions
Describe and name the test for glucose:
BENEDICT’S SOLUTION: GLUCOSE
BLUE->GREEN->YELLOW->RED
- prepare a food sample and transfer 5cm^3 to a test tube
- prepare a 75C water bath
- add 10ish drops of Benedict with a pipette
- put the test tube in a test tube holder and then the water bath. Leave for 5 minutes. Make sure it is pointing away from you (because it’s irritating).
- no conc.= blue
- medium conc. = green/yellow
- high conc. = brick red
Describe the name and test for lipids: (4 steps)
LIPID: SUDAN (III) TEST
POSITIVE: BRIGHT RED
- prepare a sample (do not filter) of around 5cm^3
- add 3 drops of Sudan stain solution to a test tube using a pipette.
- Gently shake the tube.
- if positive, mixture will separate into 2 layers- top will be brick red
Describe and name the test for starch:
IODINE SOLUTION: STARCH TEST
- the solution will turn BROWNY-ORANGE to BLUE-BLACK
- make a food sample
- transfer 5cm^3 to a test tube
- add a iodine solution and gently shake the tube
no special conditions
What test do you have to use an excess of? Why?
- Benedict’s solution (glucose)
- this us to ensure all of the glucose reacts
Which test must the tube be pointing away from you?
- glucose (Benedict’s test)
Which test has to be heated to occur?
- glucose (Benedict’s)
How to make a food sample?
- break up a piece of food using a pestle and mortar
- transfer the food to a breaker
- add distilled water
- mix with a glass rod to dissolve some of the food
- filter the solution via a funnel lined with filter paper to remove solid food
What is glucose found in: (name 3)
- biscuits
- cereal
- bread
what food contain starch? (Name 3)
- pasta
- rice
- potatoes
What is used for protein tests?
- meat
- cheese
What is used for the lipid test?
- olive oil
- margarine
- milk
