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

1. NUTRITION

2. NUTRITION
How an organism
obtains and uses
food

3. NUTRIENT
The chemical
component that
makes up food

4. FUNCTIONS OF FOOD
1.Energy
2.Growth and repair of cells
3.To control metabolism

5. ELEMENTS IN FOOD
Elements combine
together in different
ratio to form
biomolecules

6. 6 main elements in
food;
1.Carbon
2.Hydrogen
3.Oxygen
4.Nitrogen
5.Phosphorus
6.Sulfur
5 salts of:
1. Sodium
2. Magnesium
3. Chlorine
4. Potassium
5. Calcium
3 trace elements:
1. Iron
2. Copper
3. Zinc

7. THERE ARE 4 TYPES OF
BIOMOLECULES FOUND IN FOOD
1. Carbohydrates
2.Lipids (fats and oils)
3.Proteins
4.Vitamins

8. CARBOHYDRATES
1.Carbon
2.Hydrogen
3.Oxygen

9. In the ratio of 1C:2H:1O
Formula: Cx(H2O)y
E.g. glucose is a simple carbohydrate
where x and y are both equal to 6
C6(H20)6 = C6H12O6

10. 3 TYPES OF
CARBOHYDRATES
1.Monosaccharides
2.Disaccharides
3.Polysaccharides

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

16. LIPIDS
1. Carbon
2.Hydrogen
3.Oxygen

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

19. SOURCES OF LIPIDS
1.Butter
2.Salmon
3.Oils

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

21. PROTEINS
1. Carbon
2.Hydrogen
3.Oxygen
4.Nitrogen

22. SOURCES OF PROTEIN
Nut
Poultry
Seafood
Red meat
Eggs
Beans
Dairy
Vegetables

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

27. VITAMIN GROUPS
Water soluble: vitamin B and vitamin
C
Fat soluble: vitamin A, vitamin D,
Vitamin E and vitamin K

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

32. TO CONDUCT A
QUALITATIVE
TEST FOR
PROTEIN

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

34. TO CONDUCT A
QUALITATIVE
TEST FOR
STARCH

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

36. TO
CONDUCT A
QUALITIVE
TEST FOR
FAT

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

38. TO CONDUCT A
QUALITATIVE
TEST FOR
REDUCING
SUGAR

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