3Boardworks GCSE Science: Biology Health and Diet A history of fad dietsBoardworks GCSE Science: BiologyHealth and DietWhich diets are designed for weight loss?Which diets have a scientific basis?
4Boardworks GCSE Science: Biology Health and Diet You are what you eat!Boardworks GCSE Science: BiologyHealth and DietWhen food is digested its components enter the blood.carbohydrateglucosefatfatty acids + glycerolproteinamino acidsMolecules used for growth and repair become part of the body.Those used as energy sources are lost as CO2 and H2O.
5What are cells made from? Boardworks GCSE Science: BiologyHealth and DietDifferent nutrients are incorporated into each part of a cell:membrane:fats and carbohydratenucleus: proteincytoplasm: protein and water
6Boardworks GCSE Science: Biology Health and Diet You are what you eat!Boardworks GCSE Science: BiologyHealth and DietWhat could this food label represent?A human!
7Boardworks GCSE Science: Biology Health and Diet Different nutrientsBoardworks GCSE Science: BiologyHealth and DietTeacher notesSmall groups could be asked to discuss what they remember from KS3 and then elect a spokesperson to feed back to the rest of the class.
8Boardworks GCSE Science: Biology Health and Diet Dietary guidelinesBoardworks GCSE Science: BiologyHealth and Dietvitamins and minerals (1%)protein (14%)carbohydrate (50%)fat (35%)The amount of each type of nutrient a person needs varies between individuals. What factors might affect how much a person needs?
9Boardworks GCSE Science: Biology Health and Diet Lack of proteinBoardworks GCSE Science: BiologyHealth and DietProteins in meat and fish are called first-class proteins because they contain all the essential amino acids that humans need in their diet.Recommended daily allowance (RDA) of protein (g)= 0.75 x body mass (kg)What is the RDA of protein for a 60 kg student?RDA = 0.75 x 60 kg= 45 gramsA protein deficiency illness called Kwashiorkor can cause a swollen belly and weak immune system, and is common in developing countries.
10Why do some people need more food? Boardworks GCSE Science: BiologyHealth and DietMetabolism is the series of chemical reactions or ‘life processes’ in the body. Different amounts of energy are used in different life processes.digestion (10%)exercise and warmth (20%)growth and repair (70%)Metabolic rate is the rate at which cells uses energy, and this varies between individuals. Why does metabolic rate increase during exercise and cold weather?
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12Chemical and physical digestion Boardworks GCSE Science: BiologyHealth and DietTeacher notesThis four-stage animation illustrates the processes of physical and chemical digestion. Suitable prompts could include:What actually breaks the food down? Enzymes can only break down the food on the edge of a lump. What happens in the mouth to speed up digestion?Why is saliva so slimy?Some people say you can still swallow if you are hanging upside down. What do you think?What's the difference between physical and chemical digestion?The stomach lining can defend itself from acid but the small intestine cannot. How does your body neutralize stomach acid?Toxins like alcohol may be absorbed with the nutrients from your small intestine. What is the first organ the blood takes them to?What’s left to enter the large intestine once nutrients have been absorbed?
13Boardworks GCSE Science: Biology Health and Diet Enzymes at workBoardworks GCSE Science: BiologyHealth and DietEnzymes digest food in the mouth, stomach and small intestine.Enzymes break down large food molecules into smaller ones that can be absorbed by the blood. This is called chemical digestion.Different types of food are broken down by different enzymes.
14Boardworks GCSE Science: Biology Health and Diet Enzymes of digestionBoardworks GCSE Science: BiologyHealth and Diet
15Boardworks GCSE Science: Biology Health and Diet Helping enzymesBoardworks GCSE Science: BiologyHealth and DietEnzymes are not the only substances involved in chemical digestion.Hydrochloric acid in the stomach provides the right conditions for protease enzymes to break down protein.Bile is a substance produced by the liver and stored in the gall bladder. It helps the digestion of fats by turning them into small droplets. This is called emulsification. How does this help lipase enzymes?The smaller droplets have a larger surface area, which speeds up the rate at which lipase digests the fat.
16Boardworks GCSE Science: Biology Health and Diet Which enzyme?Boardworks GCSE Science: BiologyHealth and DietTeacher notesThis drag and drop activity could be used as a plenary exercise to check students’ ability to identify facts about digestive enzymes. Class voting or the use of coloured traffic light cards could be make this a whole-class exercise. Alternatively, students could be asked to complete the table in their books and the activity could be concluded by the completion on the IWB.
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18Boardworks GCSE Science: Biology Health and Diet What is BMI?Boardworks GCSE Science: BiologyHealth and DietBody Mass Index (BMI) measures the relative amounts of fat and muscle in the body.BMI = body mass (kg) (height)2 (m)Gloria:1.45 m and 66 kgBMIConclusionBMI = 31<20underweightZak:1.85 m and 66 kg20-25normalBMI = 1925-30overweight>30obeseWhat are their health risks?Obese people have an increased risk of arthritis, diabetes and heart disease. People who are underweight tend to have poor immune systems and often get ill.
19Are you right for your height? Boardworks GCSE Science: BiologyHealth and DietIn 2002, 22% of boys and 28% of girls aged 2-15 in the UK were overweight or obese. Statistics show that obesity levels, among both young people and adults, are rising.Calculating a person’s BMI can be useful, but the formula can overestimate the proportion of body fat in people who are muscular.This is because muscle is denser than fat.Photo credit: Peter WernerTeacher notesData on childhood obesity/overweight from International Obesity Taskforce (www.iotf.org)This means it is helpful to use extra measures to help judge how healthy a person is, such as waist circumference.
20Boardworks GCSE Science: Biology Health and Diet What is blood pressure?Boardworks GCSE Science: BiologyHealth and DietBlood pressure is a measure of the pressure exerted by the blood against artery walls. Blood pressure varies with:heartbeat strengthhealthblood volumeage.fitnessBlood pressure is measured as two numbers, e.g. 120/80. What do these numbers show?Photo credit: Karen BarefootThe numbers show pressure readings in mm of mercury.
21Systolic and diastolic Boardworks GCSE Science: BiologyHealth and Diet“Blood pressure one-twenty over eighty.”The big number (‘120’) is the systolic pressure. This is the blood pressure during a heartbeat.The small number (‘8’) is the diastolic pressure. This is the blood pressure in-between heartbeats.
22How does blood pressure affect health? Boardworks GCSE Science: BiologyHealth and DietHigh blood pressure can make blood vessels more likely to burst, and can cause strokes and kidney damage.Low blood pressure can cause dizziness, fainting and poor circulation.AgeSystolicDiastolicThe older you get, the higher your blood pressure naturally becomes.1080-100601590-1106020704080Kevin is 38 years old and his blood pressure is 180/90. What advice would you give him?
23Boardworks GCSE Science: Biology Health and Diet Lifestyle assessmentBoardworks GCSE Science: BiologyHealth and DietKevin’s GP quizzed him about his lifestyle, tested his blood and referred him to a health centre.Excess salt is known to increase blood pressure in about 30% of the population.What else could Kevin do to improve his health?
24Boardworks GCSE Science: Biology Health and Diet Health and fitnessBoardworks GCSE Science: BiologyHealth and DietHealth and physical fitness are different.A healthy person is free from disease or abnormality.A fit person has good cardiorespiratory, aerobic and muscular endurance.Kevin’s GP wants his cardiovascular fitness to improve so that he puts less strain on his body. His personal trainer wants other sorts of fitness to improve.What types of exercise should Kevin do?
25What is wrong with fast food? Boardworks GCSE Science: BiologyHealth and DietFast food and takeaways such as curries, burgers and pizzas are high in unhealthy nutrients such as saturated animal fats, sugar and salt.Fast food usually contains very little fibre, vitamins, minerals or unsaturated vegetable oils, which are important for a healthy diet.Photo credit (top right): Jim BroughtonPhoto credit: (bottom left): Ede BittleTeacher notesSee the ‘Food Chemistry’ presentation for more information on fats and health.
26Boardworks GCSE Science: Biology Health and Diet Unhealthy diets?Boardworks GCSE Science: BiologyHealth and Diet
27Boardworks GCSE Science: Biology Health and Diet What is cholesterol?Boardworks GCSE Science: BiologyHealth and DietCholesterol is a lipid found in cell membranes and is used in the production of hormones and bile.Cholesterol is transported in the blood by molecules called lipoproteins, of which there are two types:high-density lipoprotein (HDL): often called ‘good cholesterol’low-density lipoprotein (LDL): often called ‘bad cholesterol’.Cholesterol levels depend on diet and genes, but high levels of LDL have been linked to eating lots of saturated fats and few mono/polyunsaturated fats.
28Good and bad cholesterol Boardworks GCSE Science: BiologyHealth and DietHow do ‘good’ and ‘bad’ cholesterol affect a person’s health?
29Cholesterol and heart disease Boardworks GCSE Science: BiologyHealth and DietWhy is LDL called ‘bad cholesterol’?Excess LDL is deposited on the walls of blood vessels, which can lead to clots in the arteries. This can starve the heart of oxygen and cause heart disease.Why is HDL called ‘good cholesterol’?HDL returns cholesterol to the liver where it is metabolized.The risk of heart disease may be reduced by:lowering blood cholesteroleating more HDL than LDLgentle daily exercise.
30Boardworks GCSE Science: Biology Health and Diet Taking actionBoardworks GCSE Science: BiologyHealth and DietKevin’s blood test showed high cholesterol, but not high enough to require drug therapy to reduce it.This margarine claims to cut blood cholesterol by 10%, but it costs four times as much as normal margarine.Photo credit: Bruno NeevesShould Kevin buy the margarine? What extra information would help him decide?
31Boardworks GCSE Science: Biology Health and Diet What are statins?Boardworks GCSE Science: BiologyHealth and DietThe plant extracts in margarine that lower cholesterol are less effective than cholesterol-lowering drugs called statins. Should these drugs be available without a prescription?Yes! People should be allowedto self-medicate.No! People with normal cholesterol might take them and they wouldn’t be checked for side-effects like liver damage.What do you think?
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33Boardworks GCSE Science: Biology Health and Diet Glossary (1/2)Boardworks GCSE Science: BiologyHealth and Dietblood pressure – The pressure in the arteries during and between contractions of the heart.body mass index – A measure of a person’s weight in relation to their height.chemical digestion – The process of breaking large food molecules into smaller ones using enzymes.fitness – Strength, stamina, flexibility, agility, speed and cardiovascular efficiency.health – Freedom from disease and injury.heart disease – An abnormal condition of the heart or the arteries that supply the heart.
34Boardworks GCSE Science: Biology Health and Diet Glossary (2/2)Boardworks GCSE Science: BiologyHealth and Dietlipoproteins – Molecules that carry cholesterol in the blood and which are either high density or low density.metabolic rate – A measure of how fast chemical reactions occur in cells.obese – A person who is very overweight and has a BMI of over 30.physical digestion – The breaking up of pieces of food by chewing it in the mouth and churning it in the stomach.saturated – A type of animal fat that raises blood cholesterol levels and increases the risk of heart disease.unsaturated – A type of fat from vegetable and fish oils that helps lower blood cholesterol levels and reduce the risk of heart disease.
35Boardworks GCSE Science: Biology Health and Diet AnagramsBoardworks GCSE Science: BiologyHealth and Diet
36Boardworks GCSE Science: Biology Health and Diet Multiple-choice quizBoardworks GCSE Science: BiologyHealth and DietTeacher notesThis multiple-choice quiz could be used as a plenary activity to assess students’ understanding of health and diet. The questions can be skipped through without answering by clicking “next”. Students could be asked to complete the questions in their books and the activity could be concluded by the completion on the IWB.