1. 1.3.4 Biomolecular Sources and the Components of Food

2. Carbohydrates Carbohydrates contain the elements Hydrogen Oxygen
Carbon
Hydrogen
Oxygen
Usually in the ratio of 1C:2H:1O
They have twice as many hydrogen molecules as oxygen molecules

3. 3 Types of Carbohydrate
Monosaccharides
Disaccharides
Polysaccharides

4. Monosaccharides These are single sugar molecules simple sugars
soluble in water
sweet to taste
smallest carbohydrate unit
Examples: glucose, fructose
Found in: fruit

5. Disaccharides These are
two monosaccharide sugar units joined together – known as double sugar molecules
soluble in water
sweet to taste
Examples: sucrose, lactose, maltose
Found in: table sugar, milk

6. Polysaccharides These are
Many monosaccharide sugar molecules joined together
Not soluble in water
Do not taste sweet
Example: starch, cellulose
Found in: bread, pasta, cereals

7. Lipids Lipids are a diverse group of substances which include
fats (solid at room temp.)
oils (liquid at room temp.)

8. Structure of Lipids They are made up of the elements carbon hydrogen
oxygen
But not have the same ratios as carbohydrates.
They are made up of two main types of molecules
Fatty acids and
Glycerol

9. Types of Lipid Two of the main types of lipids are Triglycerides
Phospholipids

10. Triglyceride This is the smallest lipid It is made up of
3 fatty acid molecules
and
1 glycerol molecule

11. Phospholipids
If one fatty acid of a lipid molecule is replaced by a phosphate group then a phospholipid is formed

12. Sources of Lipids
Fat – in and on meat
Butter (80% fat)
Cooking oils

13. Proteins Proteins contain the elements Carbon Hydrogen Oxygen Nitrogen
Some may also contain sulphur, phosphorous or iron
Proteins are found in lean meat, fish, pulses, soya and eggs

14. Structure of Proteins Proteins are made up of long chains of
amino acids
There are 20 common and several rare amino acids found in proteins
Amino acids are joined together by
peptide bonds
This results in the formation of polypeptide chains

15. Vitamins Vitamins are essential organic catalysts of metabolism
Needed in small amounts, cannot be produced in the body
Must be supplied continuously and in sufficient quantities
Differ from each other chemically

16. Vitamins
We need Vitamins A, B, C, D, E and K in our diets to keep us healthy
Vitamins can be water soluble or fat soluble
Vitamins B and C are water soluble
Vitamins A, D, E and K are fat soluble

17. Sources of Vitamins Green leafy vegetables, Eggs, Cheese, Carrots
Lean Meat, Cereals, Nuts C
Citrus Fruits, Green vegetables, Turnips D
Milk and Milk products, Sunlight E
Vegetable oils, fish, nuts K
Green leafy vegetables

18. 1.3.6 Structural Role of Biomolecules

19. What does the ‘Structural Role of Biomolecules’ mean?
Structure = the way in which something is built e.g. timber structure, steel structure
Role = function/job or position
Biomolecules = carbohydrates, fats, proteins
Structural Role of Biomolecules = the function/job of carbohydrates, fats, proteins in making various parts of living things

20. Structural role of Carbohydrate
Cell Structure
Cellulose (polysaccharide) found in plant cell walls
Chitin (polysaccharide) found in fungal cell walls and insect exoskeletons

21. Structural role of Proteins
Cell structure
Proteins are fibrous (threadlike) in nature.
They combine with phospholipids to from cell membranes (lipoproteins)
Keratin is the structural protein in skin, hair and nails
Myosin is the structural protein in muscle

22. Structural role of Lipids
Cell Structure
Important storage molecules in organisms
Heat insulation – e.g. under the skin
Protection around body organs e.g. kidney, heart
Phospholipids and lipoproteins are major components in cell membranes