everything you need to know about human nutrition. inclues all information need to know for leaving cert biology. includes protein, carbohydrates, vitmains, minerals and fats and oils. classification of them and sources of each of them
11. 1. MONOSACCHARIDES
Simplest and smallest form of carbohydrates
Known as simple sugars
Soluble in water
Sweet to taste
e.g. glucose, fructose
Source: fruit
12. 2. DISACCHARIDES
Two sugar units joined together
Soluble in water
Sweet to taste
E.g. sucrose in table sugar = glucose
+ fructose
13. 3. POLYSACCHARIDES
Consists of many sugar units joined
together
Not soluble in water
Do not taste sweet
E.g. starch cellulose
Source: potatoes, bread, pasta, cereals
14. STRUCTURAL ROLE OF
CARBOHYDRATES
Cell structure:
Cellulose (polysaccharide) found in plant cell
walls
Chitin (polysaccharide) found in fungal cell
walls and insect exoskeletons
15. METABOLIC ROLE OF
CARBOHYDRATES
They are important in the following processes:
Respiration – energy is released when glucose is
broken down to form carbon dioxide and water –
catabolism
Photosynthesis – glucose molecules are made
from carbon dioxide and water using the sun’s
energy – anabolism
17. THEY ARE MADE UP OF TWO MAIN TYPE
OF MOLECULES
Fatty acids
Glycerol
18. TYPES OF LIPIDS
Two of the main types of lipids are:
Triglycerides
1 glycerol + 3 fatty acids
Phospholipids
1 glycerol + 2 fatty acids + phosphate
20. STRUCTURAL ROLE OF
LIPIDS
1. Important storage molecules in organisms
2. Heat and insulation
3. Waterproof the body
4. Protection around body organs
5. Phospholipids and lipoproteins are major components
in cell membranes
6. myelin helps transmit messages in nerve cells
23. STRUCTURE OF
PROTEINS
Proteins are made up of long chains of amino
acids
There are 20 common & several rare amino acids
found in proteins
Amino acids are joined together by peptide
bonds
This results in the formation of polypeptide chains
24. STRUCTURAL ROLES OF
PROTEINS
Proteins are fibrous (thread like). They
combine with phospholipids to form cell
membranes (lipoproteins)
Keratin is the structural protein in skin, hair
and nails
Myosin is the structural protein in muscle
25. METABOLIC ROLE OF
PROTEIN
All enzymes are proteins and have a folded
shape. Enzymes control the chemical reactions in
cells
E.g. photosynthesis and respiration
Chlorophyll is a protein that traps the sun’s
energy during photosynthesis
26. VITAMINS
Essential organic catalysts of metabolism
Need in small amounts
Not made in the body
Must be supplied continuously and in sufficient
quantities
Differ from each other chemically
28. VITAMIN C – ASCORBIC
ACID
Function: Building connective tissue e.g. skin, blood vessels,
bones, tendons, cartilage, ligaments
Sources: Citrus fruit,
Green vegetables
Deficiency: Scurvy
Symptoms: Soft bleeding gums, bad and loose teeth
Water soluble vitamin
29. VITAMIN D
Function: Needed to absorb calcium from food. Calcium is
for healthy teeth and bone formation and their
maintenance
Sources: Dairy products
Sunlight
Deficiency: Rickets in children
Symptoms: Softening of the bones of the spinal column and
Deficiency : Osteomalacia in adults
Symptoms: The bones lose calcium and become weak – common in
Fat soluble
30. MINERALS – PLANTS
Magnesium
Function: Chlorophyll formation
Source: Salts in the soil
Calcium
Function: Helps cell wall attach
Source: Salts in the soil
31. MINERALS – ANIMALS
Iron
Function
:
Haemoglobin formation
Sources: Liver
Meat
Green vegetables
Deficiency
:
Anaemia
Calcium
Function: Bone and teeth
Sources: Milk
Cheese
Dairy
Deficiency: Rickets in children
33. 1. Label 2 boiling tubes A and B
2. Place 2ml of protein/ food being tested solution
into tube A
3. Place 2ml water into tube B
4. Add 2ml of Biuret Reagent into each tube
(Biuret Reagent = sodium hydroxide + copper
sulphate)
5. Swirl both tubes. Observe colour change
35. 1.Label two boiling tubes A and B
2.Place 2ml of starch solution/ food being
tested into tube A
3.Place 2ml water into tube B
4.Add 2-3 drops of iodine solution into
each tube
5.Swirl both tubes. Observe colour change
37. 1.Cut two pieces of brown paper to
similar size
2.Place 2-3 drops of oil on paper A
3.Place 2-3 drops of water on paper B
4.Leave both pieces of paper to dry
5.Hold both pieces up to the light when
dry
39. 1. Label two boiling tubes A and B
2. Place 2ml of glucose or food being tested
solution into tube A
3. Place 2ml of water into tube B
4. Add 2ml of Benedict’s solution into each tube and
swirl
5. Place both tubes in a water bath and heat for 5
minutes
