Human Nutrition Flashcards
What elements do carbohydrates contain
Hydrogen, carbon and oxygen
Describe the breakdown of starch into glucose
Amylase breaks starch down into maltose where maltase breaks down maltose into glucos
Describe the breakdown of protein molecules into amino acids
Pepsin breaks down protein into peptides, where protease breaks down the peptide molecule into amino acids
Describe the breakdown of lipids into glycerol and fatty acids
Lipase breaks down the lipids into glycerol and fatty acids
Describe how you can prepare a food sample
Break up a piece of food using a pestle and mortar
Transfer this to a beaker and fill with distilled water
Stir with a glass rod to dissolve some of the food
Filter using a funnel and filter paper to get rid of excess food
Describe a food test for glucose
Prepare a water bath set to 75 degrees
Add food sample to test tube and add Benedict’s solution using a pipette
Add test tube to the bath and leave for 5 minutes
If glucose present, solution colour change from blue to yellow to brick red
Describe a food test for starch
Add iodine solution and colour change of browny orange to blue/black
Describe a food test for protein
Add 2 cm of biurets test and mix by gentle shaking, if protein is present solution colour will change from blue to pink or purple
Describe a test for lipids
Sudan III to test tube and gently shake, if lipids are present a top layer will appear bright red due to the lipids being stained by the Sudan III
What is the function of Carbohydrates
Energy supply
What is the function of lipids
Provide energy and insulation
What is the role of protein
Needed for growth and repair as well as energy in emergencies
What is the role and a source of vitamin a
Liver, and to improve vision and keep skin and hair healthy
What is the role and a source of vitamin c
Citrus fruits, and to prevent scurvy
What is the role and a source of vitamin d
Eggs, and needed for calcium absorbtion
Roles of mineral ions
Calcium-
Iron-
C- makes bones and teeth
I-red meat and to make haemoglobin for healthy blood
What is the role of dietary fibre
E.g. fruit and wholemeal bread, aids the movement of food through the gut
Explain how to take a calorimetry experiment
Weigh the small amount of food, add a set volume of water to a boiling tube, this measures the amount of energy released when the food is burnt, measure water temperature, use Bunsen burner, leave until food will not catch fire anymore, measure the final temperature of the water.
How do you calculate energy in food
Energy in food = mass of water x temperature change x 4.2
What is the role of Bile
Produced in the liver and stored in the gal bladder before its release in the small intestine, it neutralises the HCL in the stomach for more alkaline conditions and emulsifies fats to increase surface area.
Describe peristalsis
The series of circular muscle contractions to push food through the gut.
Describe the role of the mouth
Produce amylase enzyme and break down food
Describe the role of oesophagus
Connect mouth and stomach
Describe the role of the liver
Production of bile
Describe the role of the stomach
Produces pepsin to digest protein, and produces HCL to kill bacteria and provide optimal Ph for protease
Describe the role of the pancreas
Produces protease, lipase and amylase
Describe the role of the large intestine
Excess water is absorbed from the food + ‘colon’
Describe the role of the small intestine
Produces protease, amylase, and lipase, and where nutrients absorbed. ‘Duodenum’ and ‘ileu’
Describe role of rectum
Where faeces stored before exiting through the anus
Explain how villi help with absorbtion
Provide large surface area for absorption, millions of tiny projections called microvilli, 1 cell thick and has a good blood supply to maintain high concentration gradient as well as decrease diffusion distance.
