8SA2 ADVERT You would not see adverts like the ones on this page today! ‘There are now much stricter rules on the claims that a food advert can make. A claim is a statement that is supposed tobe true, Adverts often contain claims to convince you to buy product, Many countries now have laws that say that all health claims must be supported by scientific evidence, We also know much more about the effects of food on the body today. Scientists think that foods that are high in fat and sugar can cause people to put on too much weight. For this reason, these types of foods cannot be advertised on children’s TV. FEB why dowe need to eat food? EB vost ctacverts al What claim is being made? b| Suggest why a company would not be able to make this claim today. Ey eckttheadvertfor doughnuts (8). al Explain why these doughnuts are supposed to be good for you. b| Suggest what is wrong with eating too many doughnuts. In what organ system is food broken down and taken into the blood? 'b| Name two parts ofthis organ system, Describe the functions of these parts a Suggest one thing people should do in order to eat healthily. ne eee ‘elo hevttuntae ‘THE VITAMIN € HAIR F000 FOR CHILDREN. ioe ese age inf FETE uo, tale Taso e tonIn science, the word diet means what you eat. Your diet provides raw materials for your body, which are needed for energy (to move, Keep warm, make new materials), growth and repat and health ‘What do scientists mean by diet? al What isa nutrient? Food substances that provide raw materials are called nutrients. ‘These include carbohydrates, fats, proteins, vitamins and minerals, bb] What does your body use nutrients for? “The main carbohydrates in food are insoluble starch and soluble sugars. There are many different sugars, including sucrose (table sugar) and glucose. “There are many different sorts of fats. Some are solid and some are liquid at room temperature. We call liquid fats ols. Fats and oils are sometimes called lipids. We also need to eat fibre. This is made of plant cell walls and is not used by the body, but it keeps us healthy by helping food nove through the intestines and stopping them getting blocked (constipation). Wholegrain cereals and breads contain alot of fibre. Water is also very important since about 65 per cent of you is water Water: w actsas a lubricant «dissolves substances so that they can be carried around the body «fills up cells so that they hold their shape 1» cools you down, when you sweat. How are water and fibre helpful for preventing constipation? Fullbran is a new cereal that contains alot of fibre. Write a health claim for use in a FullBran advert. TEI Explain ety you shoul ink plenty of water in hot weather. Food labelling Nutrition information labels show the amounts of different nutrients in a food, You can compare the nutrients indifferent foods using the ‘per 100 gram (g) of food’ values. You cannot compare foods using'per serving of food, since servings of different foods are different sizesNutrition labels also show the amount of fibre and the amount of energy stored in the food. Food labels have a list of ingredients and highlight substances that people may be allergic to (e.g. nuts, eggs). Labels also show warnings about substances that can cause problems. For example, in Europe, ifa drink contains a lot of caffeine, the label will state: ‘Not suitable for children, pregnant women and persons sensitive to caffeine’ Testing foods In many countries, government scientists test food to make sure that labels are correct. Photos C, D and E shows tests for starch, protein and fats. | cs Bo) | 3 ets of iodine you wil Prensa erat Pua Sea ee Pe the paper up ies List the names of the nutrients on label B Suggest why a breakfast cereal box states: ‘May contain races of nuts. The food referred to in label B contains two carbohydrates: starch and sugars, How much of each is there in one serving? In 2013, tests in Europe discovered that many products that claimed to be 100 per cent beef actually contained horse meat. Pres eid Poona ie! ETc} of Biuret Pee eel crt Nes) ect Gita tested butter and bread with iodine solution. Which nutrient was she testing for? 100 g of a milk powder contains 27 g of fat, 38 g of carbohydrate and 26 g of protein al Describe how you would test for the ‘nutrients in milk powder and what results you would expect 'b| Why do the totals of the nutrients not add upto 100g? tion information labelsUKING, ILS, CEE 8Ab WHY DO WE NEED THE DIFFERENT NUTRIENTS? Different nutrients are used for different things in your body. When you eat food, you gain mass. When doing everyday activities, the fuel in your food is used up and so you lose mass. To make sure your mass does not change, the amount of fuel you use should be balanced by the amount you eat Your body's main source of energy is carbohydrates. There isa lot of starch in foods like bread and potatoes, and sugars are found in sweet foods. Another source of energy comes from fats. There are a lot of fats in dairy products and fried foods. Fats are stored in your body so that there is always a source of energy. A lot ofthis stored fat ‘comes from the fats that you eat. However, if the carbohydrates you eat are not all used up, they can be turned into fat. Some fat is stored under your skin to insulate your body and help you stay warm. Meee rece minute. Long-distance athletes often drink liquids and eat eeeeonc menue iocs TE scat ene aterentiypes of nein food You lose mass doing everyday things. You gain mass when you eat CC ee Peres J FEB carettis mass has increased, Suggest why. EE ycoyouncedstarchinyourdien EEL wihat does your body use fat for? Different foods contain different amounts of energy, which is measured in kilojoules (ki). Respiration in your cells releases the energy. As your cells respire, the eneray is transferred (moved) from the nutrients, making it available for you to grow, move, think and keep warm. The amount of energy your body needs to transfer depends on your age, whether you are male or female and how active you are.See a= Sleeping 180 12000 Watching TV. 250 eed Walking slowly 470 5 Cycling slowly 660 Cyeling quickly 1090 Running fast 1700 _| FEB) *! Look atlabel 8 on page 6, How much energy in 100g of the food? b| How much of this food would provide the energy needed by someone of your age and sex for one day? c| How much of the food would provide the energy for 2hours of slow walking? ‘Average energy required per a| Between which ages do people need most energy? b| Suggest reason for this. a] Raviisa fitness trainer. His wife is the same age and works ata call centre. Who will need more energy per day? b| Explain why this is Jasmine eats more carbohydrates than she needs for energy. Explain why her mass wll change. Growth and repair Proteins are very important for making new cells tohelpusto | grow and repair our bodies. Proteins are found in foods like | meat, fish, eggs, cheese, beans and milk, | For health ‘ Allnutrients are important for health, and these include tiny quantities of vitamins and mineral salts (usually justcalled minerals). For example, vitamin Ais needed for healthy skin and eyes, and vitamin C helps cells 3 in tissues to stick together properly. Vitamin D and era ita? calcium are needed to make bones, and iron is used to x Ty iy " i make red blood cells. SUT TY B TEI Give rice important reasons fr eating fod [J 2! Stzte te good sources of eachtype of nutrient found in food. b| Why do our bodies need each type of nutrient? Present your answer asa table Fy Svsvestone effect of ack of on on your body. Explain your reasoning,Sap SPP aed toe = =D A Bn EN SACDIETS WHY IS A BALANCED DIET IMPORTANT? areconmerded ht you eat ve Bread, eo, ptaioos and No single food contains all the substances potions effuts and veatabies asi onan is thetyouneed,so youmusteat many diferent Py They aren foe state foods. Ifyou eat the right amounts ofa wide minerals variety of foods you have a balanced diet. People who have a problem caused by too much or too little of a nutrient in their diets are said to suffer from malnutrition. EER) taris balanced dee EE Wivissomeone who is very overweight suffering from malnutrition? Meat, fish, beans, Mik and daly Deficiency egos ardnuts contain rood andarinks high f0008 things made ae semicon” ods an tees diseases Soaiaees: Nagra emu aon People who lack a nutrient for a long time Fri Hest England in satocaon wih be Wen Govermi 8 Seas Goverment ae Feed ‘Saige eaten fle can suffer from a deficiency disease, ‘A| The Eatwell Guide helps people to eat a balanced diet. It Peete suena ‘Alack of protein can cause kwashiorkor (pronounced'kwash-ee-or-ker). One symptom isa large belly, caused by fluid collecting around the intestines and muscles that become too weak to hold the stomach and intestines in place. Alack of vitamin & causes night blindness (not being able to see well in low light). Scurvy is caused, by alack of vitamin C, and causes painful joints and bleeding gums. Alack of calcium and vitamin D can cause rickets, in which weak bones do not form properly. Tiredness and shortness of breath are symptoms of anaemia, caused by a lack of iron. [EB 2 What iseases are shown in photos B and C. Explain your reasoning b| Suggest a change that someone could make to their lifestyle to cure scurvy,Starvation The worst form of malnutrition is starvation, in which people lack nearly all the nutrients they need. People who are starving get thinner and thinner. Obesity People whose food contains more energy than they need may become overweight. This can cause heart disease, when fat clogs the arteries and stops enough blood reaching the heart muscle tissue. If very little blood reaches the heart muscle, it can start to die (a heart attack), which causes a painful squeezing feeling in the chest. People who are overweight are more likely to have high blood pressure, which can damage the heart or kidneys or cause blood vessels to burst. People who are very overweight are said to be obese. Obesity is increasing in many countries, so some scientists want to stop adverts for fatty or sugary foods. How will a balanced diet stop people becoming ‘overweight? {| What condition is the man in photo E suffering from? b| Suggest why he has developed this condition | What health problems is he mote likely to develop? Help with your diet Many nutrition information labels give people an idea about how much of each nutrient can be eaten in a day. These Reference Intakes (or Rls) are usually shown for adults. Note: 1 mg (milligram) = 0.001 g; ug (microgram) = 0.000001 g. foo got [iaogat oogor Ineference Junolemes! oranges butter intake t)__[bendcontainslconeans —_lowains meq bao feo [iso [ao esoohydane | 00 ag esq rm ren 50g) 103 ag aa fat 709 254 09 aia be 2g ea 2g og erin [o00ug | 0g Sug maniac | eomg | omg [sg escimn | a00mq [38mg atmg [15m rar ang 13mg O3mg [02mg Pe ence Crema) made using leaves, grass ies g ecm? ‘| How much wholemeal bread would anadult need to eat for itto provide alltheir energy needs for a day? Give your answer tothe nearest 100 9. b| Suggest why only eating wholemeal bread would bea bad idea. ¢| Inwhat way would putting butter on the bread be good?Pees eee wn noe of years, often to solve the problem of foods going bad. Yoghurt, for example, was probably discovered by accident about 7000 years ago in the Middle East. Peer Cae Meu ceca Pee ee iaase eek ocr Lud food lasted longer. Food technologists are still inventing new foods that last longer, taste better, ook better or are healthier. B | investigating the use of electricity to Certo cued pte kn! is automated in huge factories. This involves a lot of engineering, ee na ou) drying are ways of changing foods to make them Pa ‘Notall food technologists develop new foods. Some of them test foods to ensure that they contain the right ingredients Pree et eee oes ace seu) eee cancer wae technology. The researchers in photo B, for example, are Peer mu Mckee een Nc iiog eee eens Coico aa eee ae er ep MNS aco) Mend ceckee ee ned eran dL egos of chemistry, biology and maths and go to university to Pee ceca ede) leave school and join a company that will train you as a food technologist while you work for them.Food technologists who develop foods need to be inventive, They first identify something that people want (eg. a snack bar with less sugar). They then think up different ideas to do this. They try out each idea and find the best one. SNe ence came Iacy think about whether they can: substitute something (eg, take an Greene OMe eta something else) CMe eM co CE extra ingredient to a food) a eee ee eae eer eed eters au cd make another) nud eed eRe Se amounts of the different ingredients) EE Suggest bar with less sugar. nee ee Sen eee one eee you would like to see for sale, People have asked a pizza company to use healthier pizza bases. The nutrition ingredients information for the existing pizza base Bleached white flour, water, glucose, suc isshown. salt hydrogenated vegetable all (toad Gist carte WAR hich the piza base xanthan gum {to add stretchiness) could be made healthier. Choose one way and explain two ideas for changing the pizza base in this way. Choose one idea and design a delivery box to advertise your new pizza base.Proteins, fats and most carbohydrates are too big for your body to use and need to be broken down into smaller pieces. Digestion turns large insoluble molecules into smaller soluble ones. Digestion occurs as your food passes through your gut (a tube made up of different organs). The gut and some other organs that help digestion (such as the salivary glands, liver and pancreas) form the digestive system. | What does the digestive system do? | Why do we need to digest food? 4. Pulting food in your mouth is 2. When you swallow, food enters ingestion, Your teeth grind the oesophagus (or gullet). Muscles food into small pieves and mix in the oesophagus contract to make the itwith saliva, which is tube above the food narrower, and this produced by your salivary pushes food towards the stomach. glands. Saliva is an example of Food is moved through the whole a digestive juice — ithelps ut in the same way. digest food. It also makes food easier to swallow. — 3, In the stomach, food is chumed up with acid (pH 1-2) ‘and more digestive __ Juices are added. tongue salivary glands —~ pancreas 4, In the small intestine, more digestive juices are ‘added (including from the pancreas). The liver ‘adds a substance to help digest fats. Small molecules of digested food are then absorbed (taken into the body) here. ‘The appendixis a small tube that helps some animals to digest grass. In humans it helps CMe acnnec urge) Coetieto Nee aes e rac 65, Food that we cannot digest (0.g. fibre) goes into the large intestine, where water is removed This forms a more solid material called faeces (pronounced 'fee-sees') 6, The rectum stores faeces, which are then pushed out of the anus in a process called defaecation or egestion. It takes about 24~48 hours for food to go through the gut. (Note that defaecation is getting rid of undigested food. Excretion is getting rid of wastes produced by your cells.) Draw a flow chart to show what happens in each organ of the gut. What are ingestion and egestion? Describe how food is pushed through the gut.Gut bacteria Bacteria are microorganisms (organisms you need ‘a microscope to see). Although they are tiny, your intestines contain about 1 kilogram (kg) of them! Some of these bacteria are useful, but other types are harmful. The bacteria in your gut feed on your food and can digest some foods that your body cannot. The bacteria grow and reproduce using some of these digested molecules, but the rest of the molecules can be absorbed into your body. Deen ay help control harmful gut bacteria, Enzymes Enzymes are substances that speed up the breaking down of large molecules into smaller ones. Substances that speed up reactions (without being changed themselves) are called catalysts. Enzymes are biological catalysts. Most of the enzymes needed for digestion are produced by your body and are found in the various digestive juices that are added to food as it travels ‘through the gut. Amodel that helps us think about how enzymes work compares them to scissors. The enzymes help to cut through the connections that hold the molecule together. Give one benefit and one disadvantage of having bacteria in your gut. [Ei] ®! How do digestive juices help wth digestion? b| Use the scissors model to explain how ‘enzymes work.us 8AcSURFACE AREA HOW ARE SURFACE AREAS CALCULATED? ‘The area of a rectangle is worked out using this formula: area of a rectangle ith length x ‘Area is measured in square units, like metres squared (m?), centimetres squared (cm), millimetres squared (mm). So, ifthe length and width are in metres (m), the area isin Atennis courts a rectangle 23.78 m long and 10.97 m wide: area = 23.78 x 10.97 = 260.87 m? BEB) Wists tne ars of soca ich that 100 mlong and 45 m wide? Show your working, ‘The total area of al the surfaces on a three-dimensional shape is called the surface area. It is important because it can affect the speed at which things happen. adiators andair conditioning evaporators have folds or fins on them to increase their surface areas. This means that more energy can be transferred from them in a certain length of time. Calculating surface areas ‘Acube has six faces. To find the surface area of a cube you find the area of each face and add them all together. Some cells are roughly cuboid, sowe can estimate the total surface area by finding the total of the eed areas of a cell’ six rectangular faces. evaporators have large te top area = 12x10 = 120une i fend area = 10*10 = 100ure— 10m" Faun opm FyEstimate the surface area of an approximately cuboid cel, with length 10 um, width 15 umm Ae e 4 2004 eee ie and eo 20 um. Show your ‘Surface area of the cuboid = 240 + 240 + 200 = 680 jim? —— Iffood is given a greater surface Sem. ee es a area, there is more room for 5 Tee a2 ‘enzymes to get to work and break ” down the food. This is why, for se example, teeth are important for grinding up food. sem Surface area is also important for 30m | the small intestine; the larger its surface area the faster it can absorb ; - (Ggased food surface are of argo cube: {re woe ib pti 6x66) 216 on? surface area of one smal cube =8 x ( x 3) FE 42 0id measures 8 cmiong, 54 cm? 4mm wide and 6 cm tall a| Calculate its surface area, b| The cuboid is cutin half along itslongest edge. Calculate its Tena new surface area. there are eight smaller cubes, so total surface area = 54% 8 432 em? Surface area : volume ratio Explain why a sugar cube dissolves more slowly ina cup of coffee than the same amount of loose sugar granules. ‘The surface area : volume ratio is the surface area divided by the volume, or Sutface area volume The bigger the surface area : volume ratio, the more surface area something has per unit volume. Cells need large surface area volume ratios to be able to take enough of the substances they need from their surroundings. Explain why the same amount of food is digested faster when itis in small pieces compared with large pieces, [Ey Lok atciagram 0.cateuiate the surface area: volume ratio of al the large cube b| one of the small cubes. Show your working,Enzymes break up large molecules into smaller, soluble ones. ‘The small molecules can then be absorbed by the small intestine. FE 2! Wheres cigestec food absorbed? b| Explain which molecules in diagram A can be absorbed. starch molecule + Models help us to think about how complicated things happen. ee Diagram B is a model of the small intestine. Visking tubing is a thin ee @ material containing tiny holes that only small molecules can pass ® 9 through. In diagram 8 the inside of the tubing represents the inside of smaller glucose the small intestine. The water around the tubing represents the blood. molecules sc) Ce ee Pears — Visking tubing mixture of water, enzymes and starch water What would you expect to find in the water at tightly led the end of the experiment shown in diagram B that was not there at the start? Explain your reasoning, Ce al intestine a| Why do your cells need to respite? b| Which parts of the blood carry the substances needed for respiration? Once absorbed, digested nutrients are dissolved in the blood plasma (the liquid part). Blood carries, the nutrients around the body for cells to use. For example, all your cells need glucose in order to release energy (using respiration). All particles naturally spread out. This is called Glucose Water molecules molecules diffusion. Ifthere are more particles of a substance peed (leer in one area than another, eventually the particles random random even spreading become evenly spaced due to diffusion. After a meal, Ce Spoke of molecules there are many more digested nutrient molecules inside the small intestine than in the blood. This causes an overall movement of these molecules into the blood, by diffusion. Particles move randomly in all directions. So some ‘1 blood molecules of glucose will move from the blood Decne) into the small intestine, but many more go the other way. There is an overall movement of glucose See molecules in one direction.Whatis diffusion? Why do some glucose molecules move out of the blood and others move into it? Explain how diffusion allows the small intestine to absorb soluble molecules but not insoluble ones. intestine has ‘many folds Se muscle layers vil Small intestine adaptations The greater the surface area, the more room there is for molecules to pass between the inside of the small intestine and the blood. So, a greater surface area allows more diffusion of molecules. This allows more glucose to be absorbed more quickly. To increase its surface area, the wall of the small intestine is folded. It also contains lots of little finger-shaped vill (one is called a villus), To further increase surface area, each villus cell has a folded top (that forms microvilli, one is a microvillus).. The wall of the villus is only one cell thick so that substances do not have to diffuse very far. ‘This inoreases the speed of absorption. microvilli cells on surface of vill How isthe small intestine adapted to absorbing digested nutrients quickly? al Give one short-term effect of drinking alcohol on the digestive system. b| Explain why this may cause fewer nutrients to get into the blood. ¢| Explain why someone who drinks alcohol may suffer from malnutrition, You can think ofthe human small intestine as a tube which is about 6.5 m long and has a diameter of 25 cm. A tube of these dimensions has a surface area of about 0.51 m?. Why is this different from the area given in the fact box? Alcohol When alcohol is drunk, fewer digestive enzymes are released into the small intestine. Drinking alcohol can damage the villi and cause them to become shorter.Most food companies put nutrition information labels on food packaging. Many companies also add traffic lights. Red means high, orange means ‘medium and green means that a food is low in a certain nutrient. The more green the better. The percentage of the Reference Intake ina serving may also be shown. Companies must show ingredients on packaging and most foods must be dated. A’best before! date tells you how long a food's taste will be at its best. A food is usually safe to eat after this date but does not taste as good. Foods with a‘use by'date may cause harm after this date, often because harmful bacteria grow in them. A| Food traffic lights: some fats (saturates) increase the risk of heart disease more than other fats. Salt helps our nerves Perea cee ee Ue oe ie eee ‘al Suggest why food producers use SE eT erie est oni fod seam oS fea gM, << advertise some foods aight in photo A. In some countries there are strict rules on some words found b| What does each nutrient do? ‘on food packaging, For example, in the EU foods labelled | Suggest why only certain nutrients i ‘organic’ must be produced without the use of artificial appeat on food traffic lights fertilisers and pesticides. A low fat food must contain less Describe how bacteria canbe both than 3g of fats per 100 g of food. A reduced fat light orlite” Cee oen teerul ithe digsative food must contain 30 per cent less fat or energy than another system, . food of the same type. Hh 2202 fow chara show how els However, many other words have no rules, including {et a fuel for respiration after you have ‘traditional style; finest’and handmade. eaten starch, IZON | Pot mC 3ANIC, ‘ORGANIC Some people think that putting nutritional information labels on all DHAOMEGA Pere M tut a Wir ood Beer oat Pee RareCors