Human Nutrition Flashcards
What are carbohydrates made from (including the elements)?
Starch/glycogen are long chains of carbohydrates which are made up of smaller chains, like glucose/maltose
Carbon, Hydrogen and Oxygen
What are proteins made from (including the elements)?
Long chains of amino acids
Carbon, Hydrogen, Oxygen and Nitrogen (CHON)
What are lipids made from (including the elements)?
Built from fatty acids and glycerol
Carbon, Hydrogen and Oxygen
What is the test for Glucose?
Benedict’s Test
This is the hot tub one
What is the colour change for a Benedict’s Test?
Negative = Blue
Positive = Green to Yellow to Red (depends on conc.)
What is the test for Starch?
Iodine solution
What is the colour change for Iodine solution?
Negative = Orange
Positive = Blue/black
What is the test for Protein?
Biuret’s test
What is the colour change for Biuret’s Test?
Negative = Blue
Positive = Pink/Purple
What is the test for Lipids?
Sudan III stain Test
What is the colour change for Sudan III test?
Negative: Mixture will remain colourless
Positive: Mixture will separate into two layers; top layer will be red
What do carbohydrates do in the body?
Provide energy
What do lipids do in the body?
Provide energy
Act as an energy store
Provide insulation
What do proteins do in the body?
Needed for growth and repair of tissue
Provides energy (in emergencies)
What foods contain Vitamin A?
Liver
What does Vitamin A do in the body?
Helps improve vision
Keeps skin/hair healthy
What does Vitamin C do in the body?
Needed to prevent scurvy
What foods contain Vitamin C?
Citrus fruits
What does Vitamin D do in the body?
Needed for calcium absorption
What foods contain Vitamin D?
Eggs
Also made by body when skin exposed to sunlight
What does calcium do in the body?
Needed to make bones and teeth
What does iron do in the body?
Needed to make haemoglobin for healthy blood
Why is water needed in the body?
Nearly every bodily function relies on water.
Need to constantly replace water we lose through urinating/breathing/sweating
What does fibre do in the body?
Aids the movement of food through the gut
What is a balanced diet?
Gives all of the essential nutrients you need in the right proportions
Why do pregnant women need more energy than other women?
They have to provide energy for both them and their babies development
Describe an experiment to measure how much energy is in food.
- Weigh a food that will burn easily (preferably dry food)
- Add a set volume of water to a tube and measure its temperature
- Set fire to the food sample with a Bunsen burner and immediately hold under the water
- Repeat until the food won’t relight again, then measure the temperature change of the water
What is the formula to calculate the amount of energy in Joules
Energy in food (J) = Mass of water * Temperature change * 4.2
What is the 4.2 in the formula for?
The amount of energy (in joules) needed to raise 1g of water by 1C
What is the formula to calculate the amount of energy in Joules/Gram
Energy/g of food (J/g) = Energy in food (J) / Mass of food (g)
How can we make this experiment more accurate?
Insulate the boiling tube with foil (minimise heat loss)
What enzymes break starch into maltose?
Starch + Amylase -> Maltose
What enzymes break maltose into glucose?
Maltose + Maltase -> Glucose
What enzymes convert proteins into amino acids?
Protein + Protease -> Amino acids
What enzymes convert lipids into glycerol and fatty acids>
Lipids + Lipase -> Glycerol + Fatty acid
How is bile useful?
Neutralises the stomach acid
Emulsifies fats
What is emulsification?
The break down of fat into tiny droplets, giving a bigger SA
How does food move through the gut?
Peristalsis
Squeezes balls of food (boluses) through the gut
What does the mouth do?
Teeth break down the food (Mechanical digestion)
Secretes amylase in the saliva (Chemical digestion)
What does the oesophagus do?
Muscular tube connecting the mouth and the stomach
What does the stomach do?
Pummels the food with its muscular walls
Produces protease enzyme pepsin
Produces HCl to kill bacteria and provide optimum pH for protease
What does the liver do?
Where bile is produced
What does the gall bladder do?
Where bile is stored
What does the pancreas do?
Produces protease, amylase and lipase. Releases these into the small intestine
What does the large intestine (colon) do?
Excess water is absorbed from the food
What does the small intestine do?
Produces amylase, lipase and protease
Where nutrients are absorbed out of the alimentary canal
First part = duodenum; last part = Ileum
How are villi adapted to help with absorption?
Massive surface area -> walls of SA covered in villi, which are all covered with microvilli
Single permeable layer of surface cells
Good blood supply
