The Chemicals of Life All things matter both

The Chemicals of Life All things (matter), both living and nonliving things are made up of chemicals. **It was once thought that living things were different Organisms are made of organ systems organs tissues groups of cells chemicals

Chemical Elements of Living Things • Over 98% of living things are made up of 6 main chemicals. . …C, H, O, N, P, S which join together in different ratios to form all the molecules of living things. Defn: The molecules in organisms are known as biochemicals (or biomolecules).

The other 2% of is made up of. . • The salts of Cl, Na, K, Mg, and Ca • And trace elements Fe, Zn, Mn and Cu • Trace element are only required in tiny amounts 3

Chemical Elements and their Symbols Calcium Ca Nitrogen N Carbon C Oxygen O Chlorine Cl Phosphorus P Copper Cu Potassium K Hydrogen H Sodium Na Iron Fe Sulphur S Magnesium Mg Zinc Zn 4

What is Food made up of? Food is made up of: • Six chemical elements C, H, O, N, P, S • Salts of Na, Mg, Cl, K, Ca • Three trace elements (Tiny amount) Fe, Cu, Zn 5

Food is needed for: 1. Energy 2. To provide the raw materials which organisms use build new cells and repair of existing cells, organs, body parts etc. 3. To control the chemical reactions in cells i. e. to control their metabolism 6

Food Components • Elements combine in different ratios to form molecules of food • There are 4 major types of molecules of food (Organic molecules) – – Carbohydrates Lipids Proteins Vitamins • And water and minerals *** Organic compounds are complex compounds of Carbon, everything else is inorganic e. g. H O 2 7

Relative Amounts of the Food Components in the Human Body 8

What does the ‘Structural Role of Biomolecules’ mean? . . means involvement of carbohydrates, fats, proteins in making various parts of living things What does the ‘Metabolic Role of Biomolecules’ mean? . . means involvement of carbohydrates, fats, proteins in the chemical reactions in cells making various substances for living things 9

Carbohydrates contain the elements Carbon Hydrogen Oxygen The general formula for a carbohydrate is Cx(H 2 O)y x is approx = y There are twice as many hydrogen molecules as oxygen molecules 10

Carbohydrates are split into three main groups 1. Single sugar unit: monosaccharide (The basic sugar unit ) 11

2. Disaccharide: 2 sugar units 3. Polysaccharide: Many sugar units joined together 12

Monosaccharides These are single sugar molecules • There are the building blocks of other important carbohydrates Monosaccharides are: simple sugars soluble in water sweet to taste Examples: Found in: glucose, fructose fruit 13

Glucose • This is the most important monosaccharide sugar • C 6 H 12 O 6 14

Disaccharides These are • two monosaccharide sugar units joined together –(double sugar) • soluble in water • sweet to taste • May be reducing or non-reducing sugars Examples: sucrose, lactose, maltose Found in: table sugar, milk 15

Reducing Sugars • All monosaccharides and some disaccharides are reducing sugars. . i. e. capable of reducing benedicts solution (benedicts solution changes from blue to orange/red) Benedicts solution is used to determine if a food is a reducing sugar Benedicts solution is a turquoise liquid containing copper ions (Cu 2+). 16

Reducing Sugar • Is a simple carbohydrate that turns benedicts soln from blue to red/orange. 17

Polysaccharides These are • Long chains of monosaccharide sugar molecules joined together • Not soluble in water (so large) • Do not taste sweet • They are used for energy storage (glycogen and starch) • They are also structural, cellulose (fibre) Example: Found in: Glycogen, starch, cellulose Bread, pasta, cereals 18

Learning check Give examples and sources of: Examples Monosaccharides Disaccharides Polysaccharides Glucose Fructose Sources Fruit Sucrose Table sugar Lactose Milk Starch Bread, Pasta, Cellulose Cereals 19

Metabolic Role of Carbohydate Are the primary sources of energy • glucose (carbohydrate) is an immediate source of energy • Animals Catabolic • Plants Anabolic 20

Metabolism Carbs. . • Respiration – energy is released when glucose is broken down – catabolism Happens in humans, animals Eqn: … • Catabolic Reaction: Big molecules are broken down into simpler molecules • Photosynthesis – glucose molecules are made from carbon dioxide and water using the sun’s energy – anabolism Eqn: … • Anabolic Reaction: Smaller (simple) molecules are built up into bigger (complex) molecules 21

Structural role of Carbohydrate Cell Structure • Cellulose (polysaccharide) found in plant cell walls • Chitin (polysaccharide) found in fungal cell walls. • LEARN ONE 22

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. 23

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 24

Types of Lipid Two of the main types of lipids are Triglycerides Phospholipids 25

Triglyceride This is the smallest lipid It is made up of 3 fatty acid molecules and 1 glycerol molecule 26

Phospholipids If one fatty acid of a lipid molecule is replaced by a phosphate group then a phospholipid is formed 27

Sources of Lipids • Fat – in and on meat • Butter (80% fat) • Cooking oils 28

Structural role of Lipids Cell Structure • Heat insulation – e. g. under the skin • Waterproof the body • Protection around body organs e. g. kidney, heart • Phospholipids are major components in cell membranes • Myelin helps transmit messages in nerve cells 29

Metabolic Role of and Lipids • Long term source of Energy 30

Proteins contain the elements Carbon Hydrogen Oxygen Nitrogen Some may also contain sulphur, phosphorous or iron Proteins are found in lean meat, fish, pulses i. e. beans, soya and eggs 31

Structure of Proteins are made up of long chains of amino acids =sub units (alphabet) 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 (diagram) Shapes of chain (diagram) 32

Examples of proteins • Enzymes (folded), hormones (folded), pigments (twisted), myosin and protein in muscles. 33

Structural role of Proteins Cell structure • They combine with phospholipids to from cell membranes • Keratin is the structural protein in skin, hair and nails • Myosin is the structural protein in muscle 34

Metabolic Role of Proteins All enzymes are proteins and have a folded shape. Enzymes control the chemical reactions in cells. e. g. . amylase Hormones are protein that regulate body functions e. g. hormone insulin controls amount of glucose in the bloodstream In plants. . Chlorophyll is a protein that traps the sun’s energy during photosynthesis 35

Metabolic Role of Hormones (Protein) Hormones regulate body functions e. g. the hormone insulin controls the amount of glucose in the blood Oestrogen, progesterone and testosterone are other hormones controlling human sexual development 36

Vitamins • Needed in small amounts, cannot be produced in the body • Must be supplied continuously and in sufficient quantities 37

Vitamins A, B, C, D, E and K Vitamins can be water soluble or fat soluble Vitamins B and C are water soluble Vitamins A, D, E and K are fat soluble 38

Sources of Vitamins Vitamin Source 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 39

Metabolic Role of Vitamins Definition: Vitamins are essential organic catalysts of metabolism They are needed in small amounts for the correct functioning of the body They cannot be made by the body They must be in the diet 40

Vitamin C Chemical name: ascorbic acid Solubility: water soluble Function: • for building connective tissue i. e. tissue used for attaching organs together or for protection, e. g. skin, blood vessels, bone, tendons, cartilage, ligaments Source: Citrus Fruits, Green vegetables 41

Vitamin D Chemical name: calciferol Solubility: fat soluble Function: needed to absorb calcium from food. Calcium needed for healthy teeth and bone formation and their maintenance Deficiency = Rickets, weak bones Source: Dairy products, cod liver oil, egg yolk, made by skin in sunlight 42

Vitamin deficiency disorders Lack of Vitamin C causes scurvy Symptoms: soft bleeding gums, bad and loose teeth Lack of Vitamin D causes rickets in young children and osteomalacia in adults Symptoms: Weak bones and bow-legs 43

Minerals

Minerals What are minerals? • They are salts formed from the earth’s rocks. • These mineral salts then dissolve in water and are absorbed by plants. • NB Minerals are required by organisms in very small amounts. 45

Minerals and Plants absorb minerals through their roots. They use: • Calcium (Ca) to make cell walls • Magnesium (Mg) to make the pigment chlorophyll • Nitrates (N) to make proteins • Phosphates (P) to make DNA 46

Minerals and Animals get their minerals in the food they eat. They use • Calcium (Ca) to make bones and teeth. . osteoporosis • Iron (Fe) to make the pigment haemoglobin (which helps red blood cell carry oxygen). . Anemia • Sodium (Na) for the regulation of the osmotic balance (water content) of cells and the blood. 47

Water 48

Water Cells and body fluids are made up of 70% to 95% Water 49

Physical properties of water • water is slow to heat up and cool down – helps to keep our bodies at constant temp. • Water good absorber of energy. It absorbs a lot of heat as it evaporates, so sweating and transpiration cools animals and plants. This helps to keep temperature steady. • Participates in the movement of material in and out of cells. • Water controls cell shape. 50

Chemical properties of water • It is a universal solvent for transporting substances in blood (e. g. food and oxygen) or in plants (e. g. minerals) • The medium for metabolism i. e. chemical reactions take place in it. • It is a reactant/product photosynthesis and respiration 51