Human Nutrition Flashcards
what are biological molecules?
long, complex molecules made up from smaller basic units.
give 3 examples of biological molecules?
- carbohydrates
- lipids (fats and oils)
- proteins
what elements do carbohydrate molecules contain?
3 examples
carbon
hydrogen
oxygen
how are starch and glycogen related to carbohydrates?
they are large, complex carbohydrates
-> that are made up of many smaller units joined together in a long chain
what are proteins made up of?
long chains of amino acids.
what do proteins contain?
4 things
- carbon
- nitrogen
- oxygen
- hydrogen
what are lipids made up of?
FATTY ACIDS and GLYCEROL
what do lipids contain?
3 things
- carbon
- hydrogen
- oxygen
what do you need to do before a food test?
you need to make a sample
How do you identify if a food sample contains glucose?
give the step by step test: 5 steps
By using Benedict’s test:
1) prepare a food sample. Transfer 5cm(3) to test tube
2) prepare water bath. Set it to 75 degrees C
3) add Benedict’s solution to test tube (10 drops) using a pipette
4) place test tube in water bath using a test tube holder. Leave for 5 minutes. Make sure the tube is pointing away from you
5) if food sample contains glucose, solution will become: green or yellow -> low concentrations of glucose
brick red -> high concentrations of glucose
YOU CAN DO THIS :)
I BELIEVE IN YOU!!!
<3
How do you identify if the type of biological molecules a sample contains starch?
(give the step by step test: 2 steps)
1) make a food sample. Transfer 5 cm (3) of your sample to test tube
2) add a few drops of iodine solution, gently shake the tube to mix the contents. If sample contains starch, the colour of the solution will change from browny-orange to black or blue-black
give 3 examples of starch
- pasta
- rice
- potatoes
How do you identify if the type of biological molecules a sample contains proteins?
(give the step by step test: 3 steps)
Use Biuret test
1) prepare a food sample. Transfer 2 cm(3) of your sample to a test tube
2) add 2 cm(3) of biuret solution to the sample. Mix the contents of the tube by gently shaking it
3) if the food sample contains protein, the solution will change from blue to pink or purple. If no protein is present, the solution will stay blue
give 2 examples of proteins
- meat
- cheese
give 3 examples of lipids
- olive oil
- margarine
- milk
what do you need to do to get different nutrients into your body?
you need to eat different foods
where can you find carbohydrates?
3 examples
- pasta
- rice
- sugar
what is the function of carbohydrates?
to give you energy
what is the function of lipids?
provide energy, act like an energy store, provide insulation
where can you find vitamin A?
1 example
liver
what is the function of vitamin A?
improve vision and keep your skin and hair healthy
where can you find vitamin C?
1 example
oranges
what is the function of vitamin C?
prevent scurvy
where can you find vitamin D?
2 examples
- eggs
- can also be absorbed by your body when skin is exposed into sunlight
what is the function of vitamin D?
calcium absorption
where can you find calcium (mineral ion)?
2 examples
- milk
- cheese
what is the function of calcium (mineral ion)?
make bones and teeth
where can you find iron (mineral ion)?
1 example
red meat
what is the function of iron (mineral ion)?
to make haemoglobin for healthy blood
where can you find water?
2 examples
food and drinks
what is the function of water?
every bodily function relies on water, we need constant supply to replace water lost through urinating, breathing and sweating
where can you find dietary fibre?
2 examples
- wholemeal bread
- fruit
what is the function of dietary fibre?
aids the movement of food through the gut
what does a balanced diet supply?
all essential nutrients in the right proportions
what are the six essential nutrients?
not counting with fibre
- carbohydrates
- proteins
- lipids
- vitamins
- minerals
- water
what does the energy in people depend on?
- activity level
- age
- pregnancy
why does activity level energy depend on different people?
active people need more energy than people who sit about all day
why does age energy depend on different people?
children and teenagers need more energy than older people. They need energy to grow and they are generally more active
why does pregnancy energy depend on different people?
pregnant woman need more energy than other woman, they’ve got to provide the energy their babies need to develop
how are enzymes related to digestion?
they are used in digestion. they are produced by specialised cells and released into the gut to help break down the food
what do digestive enzymes do to big molecules?
they break them down into smaller ones
what are examples of 3 BIG molecules?
- starch
- proteins
- fats
what is the happens with these BIG molecules?:
- starch
- proteins
- fats
they are too big to pass through the walls of the digestive system + they are insoluble
what are examples of 4 small molecules?
- sugar
- amino acids
- glycerol
- fatty acids
what is the happens with these small molecules?:
- sugar
- amino acids
- glycerol
- fatty acids
they are soluble and can easily pass through the walls of the digestive system
what does amylase convert starch into?
maltose (with an O)
what does maltase (with an A) convert maltose into?
glucose
what does proteases convert proteins into?
amino acids
what does lipases convert lipids into?
glycerol and fatty acids
what is another name for the alimentary canal?
your gut
what is the function of the mouth in the alimentary canal?
1) salivary glands in the mouth produce amylase enzyme in the saliva
2) teeth break down food
what is the oesophagus in the alimentary canal?
the muscular tube that connects the mouth and stomach
what is the liver in the alimentary canal?
where bile is produced
what is the gall bladder in the alimentary canal?
where bile is stored
what is the large intenstine in the alimentary canal?
- where excess water is absorbed from the food.
- can also be called colon
what is the rectum in the alimentary canal?
- the last part of the large intestine
- where the faeces ( made up mainly of indigestible food) are stored before they bid you a fond farewell through the anus
what is the function of the stomach in the alimentary canal?
- it pummels (punches) the food with its muscular walls
- it produces the protease enzyme, pepsin
- it produces hydrochloric acid for two reasons:
a. to kill bacteria
b. to give the optimum pH for the protease enzyme to
work (pH 2 - acid)
what is the function of pancreas in the alimentary canal?
to produce protease, amylase and lipase enzymes. It releases these into the small intestine
what is the function of small intestine in the alimentary canal?
- produces protease, amylase and lipase enzymes to complete digestion
- this is also where the nutrients are absorbed out of the alimentary canal into the body.
- the first part is the duodenum and the last part is the ileum
show where the mouth is in the Alimentary Canal:
look at made flashcard 1
show where the oesophagus is in the Alimentary Canal:
look at made flashcard 1
show where the liver is in the Alimentary Canal:
look at made flashcard 1
show where the gall bladder is in the Alimentary Canal:
look at made flashcard 1
show where the large intestine is in the Alimentary Canal:
look at made flashcard 1
show where the rectum is in the Alimentary Canal:
look at made flashcard 1
show where the stomach is in the Alimentary Canal:
look at made flashcard 1
show where the pancreas is in the Alimentary Canal:
look at made flashcard 1
show where the small intestine is in the Alimentary Canal:
look at made flashcard 1
what is the digestive system well adapted to?
it is adapted to its function of breaking down and absorbing food
what is bile?
something produced in the and stored in the gall bladder before it is released into the small intestine
where is bile produced?
in the liver
what does the hydrochloric acid do in the stomach?
it makes the pH too acid for enzymes in the small intestine to work properly.
what type of acid is bile?
it is an alkaline
how does bile help with the situation of hydrochloric being too acid?
since it is an alkaline, it neutralises the acide and makes conditions alkaline. This causes the enzymes in the small intestine to work better in this alkaline conditions..
what does bile do with fats?
it breaks fat into tiny droplets, resulting in a bigger surface area of fat for the enzyme lipase to work on, making digestion faster.
how is food moved?
through the gut by peristalsis
what is the job of the muscular tissue down the alimentary canal?
its job it to squeeze balls of food (called boluses) through your gut
why does the muscular tissue has to squeeze balls of food through your gut?
so that your gut doesn’t get clogged up with bits of old food
how is the squeezing action of the muscular tissue? and how is it called?
it is waves of circular muscle contraction and it is called peristalsis
show how the diagram would be for the peristalsis
look at made flashcard 2
how does villi help in the small intestine?
it helps with absorption
describe how the small intestine is adapted for the absorption of food
(there are 4 ways it is adapted)
1) very long so there is time to break down and absorb all the food before it reaches the end
2) big surface area for absorption because the walls of the small intestine are covered in millions and millions of things called villi
3) each cell on the surface of the villus has its own microvilli
4) villi has a single permeable layer of surface cells and a very good blood supply to assist quick absorption
what are microvilli?
it is little projections that increase the surface area even more
describe how the diagram of a villi looks like
look at made flashcard 3
