2Need to knowThe Function of FoodThree reasons for requiring food
3Food is needed for: Energy Growth of new cells and Repair of existing cells, tissues, organs, etc.
4Food also supplies: the materials and energy for the processes of: Metabolism andContinuity
5Learning check Why do we need food? What is metabolism? EnergyGrowth of new cells andRepair of existing cells, tissues, organs, etc.What is metabolism?Metabolism is the chemical reactions that occur in the cells of living organismsWhat is continuity?Continuity of life is the ability of an organism to exist from generation to the next
11Need to know Define Biomolecular Structures State that simple biomolecular units are composed of a combination of elements in different ratios e.g. carbohydrates Cx(H2O)y
12Types of FoodThe elements combine in different ratios to form different food components (biomolecular units) Food is made up of six different components Water Proteins Lipids Carbohydrates Vitamins Minerals
14CarbohydratesCarbohydrates contain the elements Carbon Hydrogen Oxygen The general formula for a carbohydrate is Cx(H2O)y There are twice as many hydrogen molecules as oxygen molecules
15Learning checkWhat are the six different food components? Water Proteins Lipids Carbohydrates Vitamins Minerals
16A common carbohydrateGeneral formula = Cx(H2O)y When x = y = 6 We fet the formula C6H12O6 What is the name of this monosaccharide carbohydrate? Glucose
17Another common carbohydrate General formula = Cx(H2O)y When x = 12 and y = 11 We get the formula C12H22O11 What is the name of this disaccharide carbohydrate? Sucrose
18Learning checkName the three elements that make up carbohydrates Carbon Hydrogen Oxygen What is the general formula for a carbohydrate? Cx(H2O)y
191.3.4 Biomolecular Sources and the Components of Food
20Need to knowState that simple bio molecular units are composed of a combination of elements in different ratios e.g. carbohydrates Cx(H2O)yName 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.
21Need 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
22Carbohydrates Carbohydrates contain the elements Hydrogen Oxygen CarbonHydrogenOxygenUsually in the ratio of 1C:2H:1OThey have twice as many hydrogen molecules as oxygen molecules
233 Types of CarbohydrateMonosaccharides Disaccharides Polysaccharides
24MonosaccharidesPhoto Credit fruit image by Edvin selimovicfrom Fotolia.comThese are single sugar molecules simple sugars soluble in water sweet to taste smallest carbohydrate unit Examples: glucose, fructose Found in: fruit
25Learning checkWhat are the elements that make up all carbohydrates? Carbon Hydrogen Oxygen Can you remember the general formula for a carbohydrate? Cx(H2O)y
26Disaccharides These are two monosaccharide sugar units joined together – known as double sugar moleculessoluble in watersweet to tasteExamples: sucrose, lactose, maltoseFound in: table sugar, milk
27Polysaccharides These are Many monosaccharide sugar molecules joined togetherNot soluble in waterDo not taste sweetExample: starch, celluloseFound in: bread, pasta, cereals
28Learning check Name the three types of carbohydrate Monosaccharides DisaccharidesPolysaccharides
29Lipids 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 hormoneswaxes which cover insect bodies and plant leaves.
30Structure of LipidsThey 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
31Learning check Give examples and sources of: Examples Sources MonosaccharidesDisaccharidesPolysaccharidesGlucoseFructosefruitSucroseLactoseTable sugarMilkStarchCelluloseBread, Pasta,Cereals
32Types of LipidTwo of the main types of lipids are Triglycerides Phospholipids
33Triglyceride This is the smallest lipid It is made up of Fatty Acid 1Fatty Acid 2Fatty Acid 3GlycerolIt is made up of3 fatty acid moleculesand1 glycerol molecule
34PhospholipidsIf one fatty acid of a lipid molecule is replaced by a phosphate group then a phospholipid is formedFatty Acid 1Fatty Acid 2GlycerolPhosphate
35Sources of LipidsFat – in and on meatButter (80% fat)Cooking oils
36Learning checkThe two main types of molecules that make up lipids are: Fatty acids and Glycerol The two main types of lipids are: Triglycerides Phospholipids
37ProteinsProteins 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
38Structure of ProteinsProteins 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
39Learning checkProteins contain the elements Carbon Hydrogen Oxygen Nitrogen Sometimes they contain sulphur, phosphorous or iron Proteins are made up of long chains of amino acids
40Vitamins Vitamins are essential organic catalysts of metabolism Needed in small amounts, cannot be produced in the bodyMust be supplied continuously and in sufficient quantitiesDiffer from each other chemically
41VitaminsWe 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
42Sources of Vitamins Green leafy vegetables, Eggs, Cheese, Carrots Lean Meat, Cereals, NutsCCitrus Fruits, Green vegetables, TurnipsDMilk and Milk products, SunlightEVegetable oils, fish, nutsKGreen leafy vegetables
43Learning checkWhat 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
441.3.5 Energy Transfer Reactions Anabolic & CatabolicOrAnabolism & Catabolism
45Need to know Definition of the terms: Anabolic Catabolic Give an example of each
46Anabolic ReactionsThis is where energy is used to make large molecules (e.g. C6H12O6) from smaller ones (e.g. CO2 and H2O) using enzymese.g. Photosynthesis – glucose molecules are formed from carbon dioxide and water using enzymes and the energy from the sun.This is anabolism. Energy is absorbed.
47An Anabolic ReactionEnergy being used to join two small molecules to make a larger moleculeENERGYSmall moleculeLarger molecule
48Catabolic ReactionsThis is where energy is released when large molecules (e.g. C6H12O6) are broken down to form smaller ones (e.g. CO2 and H2O) using enzymese.g. Respiration – glucose molecules are broken down by enzymes to form carbon dioxide and water and energy is released.This is catabolism. Energy is released.
49Learning check Explain Anabolism Energy absorbed. Small large moleculesGive an example of an anabolic reactionPhotosynthesisExplain CatabolismEnergy released. Large small moleculesGive an example of a catabolic reactionRespiration
51Is catabolism the opposite of anabolism? – NO In the examples just given the chemical processes (pathways*) involved in each of them are different, therefore catabolism is not the opposite of anabolism.* e.g. if you travel from A to B – you followed a certain pathway. On the return journey you may come home through C – you followed a different pathway.
52Energy Transfer Reactions Respiration – Catabolic reactionC6H12O6 + Oxygen Energy + CO2 + H2O releasePhotosynthesis – Anabolic reactionCO2 + H2O + Energy C6H12O6 + Oxygen absorbed
53Learning check Is anabolism the opposite of catabolism ? No Why? Different chemical pathways involved in both.