1.3.4 Biomolecular Sources and the Components of Food

2 Carbohydrates Carbohydrates contain the elements Carbon Hydrogen Oxygen Usually in the ratio of 1C:2H:1O Written as C x (H 2 O) y i.e. twice as many hydrogen atoms as oxygen atoms

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 O CC C C C C

5 Learning check What are the elements that make up all carbohydrates? Carbon Hydrogen Oxygen Can you remember the general formula for a carbohydrate? C x (H 2 O) y

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

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

8 Learning check Name the three types of carbohydrate Monosaccharides Disaccharides Polysaccharides

9 Learning check Give examples and sources of: ExamplesSources Monosaccharides Disaccharides Polysaccharides Glucose Fructose fruit Sucrose Lactose Table sugar Milk Starch Cellulose Bread, Pasta, Cereals

10 Lipids Lipids are a diverse group of substances which include fats (solid at room temp.) oils (liquid at room temp.) steroids which include cholesterol and some of the sex hormones waxes which cover insect bodies and plant leaves.

11 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

12 Types of Lipid Two of the main types of lipids are Triglycerides Phospholipids

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

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

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

16 Learning check The two main types of molecules that make up lipids are: Fatty acids and Glycerol The two main types of lipids are: Triglycerides Phospholipids

17 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

18 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 More amino acids are found in cells and tissues but are not in proteins Amino acids are joined together by peptide bonds This results in the formation of polypeptide chains

19 Amino Acids All amino acids contain four distinct chemical groups connected to a central carbon atom: an amino group a single hydrogen atom a carboxyl group a side chain The “acid “ part Do NOT need this for exam

20 Learning check Proteins contain the elements Carbon Hydrogen Oxygen Nitrogen Sometimes they contain sulphur, phosphorous or iron Proteins are made up of long chains of amino acids

21 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

22 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

23 Sources of Vitamins VitaminSource A Green leafy vegetables, Eggs, Cheese, Carrots B 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

24 Learning check What is a vitamin? A vitamin is an essential organic catalyst of metabolism What vitamins dissolve in water? B & C What vitamins are fat-soluble? A, D, E and K

25 Need to know State that simple bio molecular units are composed of a combination of elements in different ratios e.g. carbohydrates C x (H 2 O) y Name the element components, bio molecular components and sources of: carbohydrates, lipids and proteins. State that carbohydrates are composed of indivisible units and give examples of these e.g. –Monosaccharides – glucose; –Disaccharides – maltose; & –Polysaccharides – starch/cellulose.

26 Need to know What is a vitamin? Name one water soluble vitamin. Name one water in-soluble vitamin (fat- soluble) List the sources of these vitamins

27 END