Human nutrition Flashcards
(19 cards)
What are biological molecules?
Examples?
They are generally long, complex molecules made up from smaller basic units.
E.g. Carbohydrates, lipids and proteins.
What are carbohydrate molecules made up from?
Contain the elements carbon, hydrogen and oxygen. Starch and glycogen are large complex carbohydrates made up from many smaller units joined together in a long chain.
What are proteins made from?
Are made up from long chains of amino acids and contain carbon, nitrogen, hydrogen and oxygen atoms.
What are lipids and their structure made off?
are built from fatty acids and glycerol and contain carbon, hydrogen and oxygen atoms.
How do you prepare a food sample?
1) Get a piece of food and break it up using a pestle and mortar.
2) Transfer the ground up food to a beaker and add some distilled water.
3) Give the mixture a good stir with a glass rod to dissolve some of the food.
4) Filter the solution using a funnel lined with filter paper to get rid of the solid bits of food.
What is the test for Glucose?
Benedict’s test.
brick red = high concentrations of glucose.
Green/yellow = Low concentrations.
blue = no glucose present.
What is the test for Starch?
Iodine solution.
browny orange - blue/black if starch is present.
What is the test for Proteins?
Biuret test.
blue - pink/ purple if proteins are present.
What is the test for lipids?
Sudan 3 test.
separate red layer will form on top if lipids are present.
What do the following nutrient’s function and examples off:
a) carbohydrates
b) lipids
c) Proteins
d) vitamins A,C,D
e) mineral ions Calcium and iron
f) water
g) dietary fibre
a) provide energy e.g. pasta, rice, sugar
b) Provide energy store e.g. butter, oily fish
c) growth/repair + energy e.g. meat, fish
d) vision + skin+ hair, scurvy prevention , calcium absorption e.g. liver, fruit, eggs
e) bones + teeth, needed to make haemoglobin for blood. e.g. milk, red meat
f) every bodily function e.g. drink, food
g) movement of the gut e.g. fruit
What do you need a balanced diet and what does it give you?
-All six essential nutrients carbohydrates, proteins, lipids, vitamins, minerals, water and fibre for your gut.
- It gives you all the essential nutrients that you need in the right proportions.
What are the three main things that depend on the amount of energy that you need?
- Activity level
- Age
- pregnancy
How do you calculate the amount of energy per gram?
Mass of food (g)
Digestive enzymes
- What do they break down and do?
Starch, Proteins and fats are BIG molecules so can’t fit through the walls of the digestive system and are insoluble. Digestive enzymes break them down.
What do the following convert to:
Amylase, Proteases and lipids.
Amylase converts starch - maltose converts maltose - glucose.
Proteases convert Proteins into amino acids.
Lipases convert lipids into glycerol and fatty acids.
Where is bile stored and what is it used for?
- Produced in the liver and stored in the gall bladder before being released into the small intestines.
Bile neutralises the stomach and makes conditions alkaline where the enzymes work best.
How is food moved through the gut?
- The muscular tissue down the alimentary canal squeezes balls of food through your gut to avoid it getting clogged up. This squeezing action, which is waves of circular muscle contractions, is called peristalsis.
Label the digestive system diagram.
How are Villi in the small intestine help with absorption?
- large surface area for absorption.
- each villi has micro villi to further increase the surface area.
- single permeable layer of surface cells.
- good blood supply to assist quick absorption.
