The digestive system
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The digestive system

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The digestive system The digestive system Presentation Transcript

  •  The Digestive System
  • Unit 1: The Digestive System Understand: Keywords:1. What are the seven food groups and their role in Nutrition, Nutrients, Food, Groups, Fats, a healthy balanced diet. Carbohydrates, Proteins, Minerals, Vitamins,2. The chemical tests to detect the presence of Fibre, Water, Digestive, System, Physical, proteins, lipids, carbohydrates or sugar in foods. Chemical, Villi, Breakdown, Absorption,3. What the recommended daily amounts of Nutrients, Amino acids, Glucose, Fatty acids, vitamins and minerals are in a healthy diet. Glycerol, Obesity & Malnutrition.4. The role of the digestive system and its key organs during the physical and chemical breakdown of food.5. The role of enzymes during the chemical breakdown of foods.6. How enzymes function as catalysts.7. The role of the villi tissue in the absorption of nutrients from the gut into the blood.8. The fate of these nutrients in the body and their assimilation into cells and tissues.9. The health consequences of overeating and under eating.10. The importance of getting the balance right.
  • Science Interactive LTD Copyright 2005Overview of the digestive systemThe digestive system is a collection of cells, t________ and organs that function togetherto breakdown and absorb the daily essential nutrients, minerals and vitamins required forhealthy growth and development. The digestive system is able to breakdown proteins, fatsand carbohydrates prior to their absorption into the bloodstream. These large foodmolecules are broken down into smaller molecules by both physical and chemicald________. Name a cell, tissue and organ that belongs to the digestive system ?The digestive system: Word bank: tissues digestion Diagram of the digestive system Organ Function (complete table) Mouth Chews foods, using canines, incisors and molars. Oesophagus __________________________________ ? Stomach __________________________________ ? Liver __________________________________ ? Small Intestine __________________________________ ? Large Intestine __________________________________ ? Rectum __________________________________ ? Anus __________________________________ ?
  • Science Interactive LTD Copyright 2005Dietary intake of foodsOur dietary intake of foods like proteins, carbohydrates and lipids should provide us withthe correct amount of c________ energy to maintain our daily activities, growth (if we arechildren) and repair. An adult male requires about 10,500 kilojoules per day, equivalent toabout 100 joules per second. This is the same energy that a 100 watt light bulb uses. Takingtoo much energy, by perhaps consuming too much raw sugar or fat, can lead to weightgain, high blood pressure and eventually o________.Daily energy requirements: Word bank: chemical obesity Dietary intake, assimilation and respiration Dietary energy Diagram Respiration Respiration C6H12O6 6H2O Mitochondria Energy 6O2 6CO2 Growth & reproduction Assimilation 10,500 kJ/day (adult male) Notes All the chemical energy, vitamins and minerals that we require are provided by a balanced diet. Overeating or under eating, eating too little vitamins and minerals can cause many health problems in adults and children. It is estimated that one in four adults in the Britain will be clinically obese by 2010.
  • Science Interactive LTD Copyright 2005Deficiency diseasesYour diet needs to be b____________, providing all the necessary v_________ and mineralsthat you require for healthy growth and development. In some areas of the World, poor dietslacking in just one or two minerals or vitamins causes deficiency diseases. Scurvy is a goodexample of a deficiency disease that was common amongst sailors during the 17 th and 18thcenturies. This disease was caused by a lack of vitamin C contained in fresh fruit andvegetables, then unavailable during the long sea voyages. Scurvy can lead to bleeding of gumsand the general deterioration of muscles and joints.Deficiency diseases: Word bank: balanced vitamins Vitamin C Calcium Vitamin D Vitamin A Diagram Deficiency Scurvy Osteoporosis Rickets Night blindness Notes Scurvy: Gums begin to bleed and old wounds begin to open. Limes were carried and included in a sailors diet to avoid scurvy. Osteoporosis: A diet lacking in calcium leads to poor teeth and bone development. In older age, bones become weak and break easily. Ricketts: A lack of vitamin D causes soft bones during a child’s growth. This disease is known as rickets. Vitamin D is produced by the skin during the summer months. Night blindness This is a result of too little vitamin A in the diet.
  • Science Interactive LTD Copyright 2005A balanced dietThe amount of energy (kJ) we consume through our diet and the recommended daily amount ofm________ and v___________ we need for normal healthy growth and development is givenby the table below. Notice that these values depend on our age, our sex, when female if we arepregnant or lactating and even our lifestyles. The amount of e_______ we need can alsodepend on the type of job we have, for example a labourer digging roads will require moreenergy from their diet than someone who works in an office. Look at the information given bythe table and answer the questions.Daily vitamin, mineral and energy requirements: Word bank: minerals vitamins energy Sex Age Energy Body Wt. Protein Vit A Vit C Vit D Iron Calcium Units Years kJ kg g mg mg ug mg mg Male 15 12500 59 59 1.1 60 10 12 12000 Male 35 10500 80 63 1 60 10 10 10000 Female 15 9750 55 44 0.8 60 8 15 12000 Female 35 9750 63 50 0.8 60 8 15 12000 Female (pregnant) 35 + 1000 + 12 60 0.8 70 10 30 13000 Female (lactating) 35 +2000 63 65 1.3 75 12 15 14000Questions: 1: Why does a 15 year old male require more energy than a 35 year old male. 2: Why do females require more iron than males. 3: What role does vitamin C and calcium play in the body. 4: Why do you require less vitamin D in the summer when compared to winter. 5: Why does a lactating female require the most protein in her diet.
  • Science Interactive LTD Copyright 2005Nutrition and food groups oneThere are seven basic food groups essential for a healthy d______. The three main food groupsp________, fats and carbohydrates provide us with all the energy requirements as well ashaving specific functions in the body. Carbohydrates should make up about 55% of your totaldaily kilojoule intake. Too much fat in your diet can lead to blocked a_______ and obesity.Protein is required most during p_______ in adolescents for growth and repair. Compare thediets of a body builder, adolescent female and male and a pregnant female, how might theydiffer ?Proteins, carbohydrates and lipids: Word bank: diet proteins arteries puberty Proteins Lipids Carbohydrates Diagram Function For growth and repair. During Store of energy. Insulates the Converted readily to glucose by puberty protein demand is very body against the cold. High lipid carbohydrase enzymes found in high. Why do body builders diet lead to atherosclerosis and mouth saliva and the small take a high protein diet ? obesity. 1 in 5 adults are obese. intestine. Glucose is then respired in cells. Sources Animal flesh, Soya bean ____________________ ______________________ and nuts. ___________________? _____________________?
  • Science Interactive LTD Copyright 2005Nutrition and food groups twoThe other four food groups, although they do not provide the body with any energy, are allessential for healthy g_______ and development. A balanced diet supplying all the necessaryvitamins and minerals comes from eating a diet containing low fat meat, plenty ofcarbohydrates, fresh f_____ and vegetables. Many foods sold in supermarkets now havevitamins and minerals added to them, so that we can all take our recommended daily amount.Vitamins, minerals, roughage and water: Word bank: growth fruit Vitamins Minerals Roughage Water Diagram Function Healthy tissue growth Healthy tissue growth Helps keep regular Correct hydration is and development. and development. A bowel movements. A essential for every cell Lack of vitamins lack of iron causes low fibre diet and of course normal leads to deficiency anaemia of the blood. increases the risk of blood pressure. How diseases like scurvy Low calcium affects contracting large much water should you and rickets. bone growth. bowel cancer. drink every day ? Sources All fresh fruit and _______________ ______________ _________________ vegetables. ______________? _____________? ________________?
  • Science Interactive LTD Copyright 2005Food tests oneThe presence of proteins, starch, sugars and l_______ in foods can be tested for by using‘food tests.’ Scientists test foods for the presence of each of these food groups so they canprovide nutritional information on their food products. Where is this information normallyfound on a packet of crisps or a chocolate bar ?Food tests: Word bank: lipids Protein Lipid Starch Sugar Diagram Test Biuret’s test Paper test Iodine test Benedicts test Add 5cm3 of copper Place a small amount Place 6 drops of iodine Add 5cm3 of benedict’s sulphate and 5cm3 of of tested food on water on food sample. solution. Heat tube in sodium hydroxide. paper. Allow to dry. hot water for 5 minutes. Paper goes clear with lipids Result Control Positive Control Positive Control Positive lipid food test
  • Science Interactive LTD Copyright 2005Food tests twoStarch, a polymer of g_______ is found in many foods including all cereals and mostvegetables. Starch is broken down by the carbohydrase e________ to glucose. In thisform, glucose is readily absorbed and transported to the many billions of cells in the body.Glucose is oxidised with oxygen during cellular respiration to provide energy essential forlife. Although glucose is essential for cellular respiration, which disease might you sufferafter years of eating a high glucose diet ?Testing for starch in foods: Word bank: glucose enzyme Starch solution Corn Apple Sucrose solution Diagram Results Starch ? Starch ? Starch ? Starch ? Yes Yes Yes Yes No No No No
  • Science Interactive LTD Copyright 2005Function of the digestive organs oneEach organ or tissue in the digestive system has a specific function that helps break down thethree main food groups (proteins, lipids and carbohydrates) into small molecules so they can bea_________ into the blood stream. The majority of e___________ that chemically breakdownfoods are released by the pancreas into the small intestine. After carbohydrate, protein and lipidbreakdown, their products; sugars, amino acids, fatty acids and glycerol are absorbed acrossthe villi into the blood stream. Why can only small food molecules like glucose cross from thegut into the blood ?Digestive organs: Word bank: absorbed enzymes Teeth Food pipe Stomach Small intestine Diagram Notes Chews food and secretes Sends contents to Adds acid and proteases Most enzymes are found salvia which lubricates stomach by squeezing to begin protein here. Lipids, proteins the food and contains the chewed food (bolus) breakdown. The stomach and carbohydrates are enzyme carbohydrase, This process is called has a pH of around 2. broken down before they which begins to break peristalsis. Gravity also This also kills any are absorbed into the down carbohydrates. helps this process. bacteria found in food. blood across the villi.
  • Science Interactive LTD Copyright 2005Functions of the digestive organs twoAll nutrients including amino acids and glucose and other food groups including water,minerals and vitamins are absorbed by the v______ found in the small intestine. Theremaining organs of the digestive system including the large intestine and colon removewater from undigested material, helping to form a solid stool. The rectum stores the wastefaeces until its excretion via the anus. Blood takes the nutrients to the l_______ where theyare processed and sent via the circulatory system, the billions of cells in the human body.Digestive organs: Word bank: villi liver Liver Pancreas Large intestine Rectum and anus Diagram Notes Processes all nutrients The pancreas is found The large intestine The rectum stores the like amino acids, glucose, behind the stomach. absorbs and recycles solid waste which fatty acids and glycerol. The pancreas makes water. The stool begins contains undigested food Also breaks down excess and releases all the to become solid. This (fibre), bacteria, water amino acids forming enzymes found in the makes it easier to store and broken down blood urea. small intestine. by the rectum. cells.
  • Science Interactive LTD Copyright 2005Physical digestionThe breakdown of proteins, carbohydrates and lipids begins with chewing. Humans have amixture of c_______, incisor and molar teeth which are designed to cope with a varieddiet, which includes animal flesh and vegetables. Our canines and incisors tear and ripfood. Our molars, with their flat profile are designed to grind and chew fibrous vegetablematter like root vegetables and fruits. How does a high sugar diet affect our teeth and leadto tooth decay ?Human teeth and physical digestion: Word bank: canine Teeth Human teeth Brushing Diagram Notes Humans have two sets of The tooth (incisors, canines and Modern toothpaste now teeth. Your milk teeth are molars) are capped with white enamel. contains fluoride which replaced when you are This is made from calcium carbonate helps control oral bacteria about eight years old. Your and is the hardest substance in the and prevents tooth decay. final molars appear in your body. It can be eroded by acids found Always have a 6 monthly twenties. in foods or produced by oral bacteria. check-up at the dentist.
  • Science Interactive LTD Copyright 2005Enzymes and chemical digestionDigestive enzymes break down large f_____ molecules into smaller ones. Enzymes are allproteins, and are very specific, only having one substrate like a protein or a lipid. Theybehave like c_________, able to speed up the rate of reaction and can be recycled by thedigestive system. There are three main types of enzymes found in the digestive system:proteases, carbohydrases and lipases. Look at the table below to find out the function andlocation of each type ?Types of digestive enzymes: Word bank: food catalysts lipases Proteins Carbohydrates Lipids Diagram Enzymes Proteases Carbohydrases L_________ -stomach -salivary -pancreatic -pancreatic -pancreatic Products Amino acids Sugars Fatty acids and glycerol
  • Science Interactive LTD Copyright 2005How enzymes function oneFor proteins, lipids and c____________ to be absorbed from the small i_________,into the blood, they must be broken down into small molecules. Digestive enzymesbreakdown food chemically. An enzyme’s substrate will bind to the enzyme’sa_________ site where chemical bonds are broken producing smaller moleculeswhich can then be absorbed into the b________ stream.How enzymes break down food molecules: Word bank: carbohydrates intestine active blood Stage one Stage two Stage threeDiagram SubstrateSubstrates Products Enzyme substrate complex active site active site active site Enzyme (catalyst) Enzyme Enzyme (can be reused) ProductsNotes Step one Step two Step three Substrates like proteins, Chemical bonds are broken New products like glucose are carbohydrates and lipids bind by the enzyme to form formed which then leave the to the enzyme’s active site. monomers. enzyme’s active site.
  • Science Interactive LTD Copyright 2005How enzymes function twoEnzyme are biological catalysts which will increase the rate of b__________ of proteins,carbohydrates and lipids without be used up themselves. Enzyme catalysts are able to lower theactivation energy required for new products like sugars and amino acids to be produced fromsubstrates like carbohydrates and proteins. The reaction takes place in an area of the enzymewhich is called the active site. Carbohydrases, Lipases, Proteases Enzymes are biological catalysts Not used up during the reaction Lower the activation energyEnzymes as biological catalysts: Word bank: breakdown Breakdown of carbohydrates by carbohydrase Diagram Carbohydrase + Carbohydrate Carbohydrase + sugar molecules Sugar e Sugar ra t Sugar hyd rbo Sugar Ca Sugar Catalyst Enzyme Catalyst Enzyme active site active site active site active site Notes Substrates like carbohydrates collide and temporarily bind to the enzyme’s active site on its surface. The bonds in the substrates are weakened by the enzyme. The bonds are broken and new products are formed. These products (sugar) then leave the enzyme’s active site, leaving the enzyme catalyst unchanged and able to participate in further reactions.
  • Science Interactive LTD Copyright 2005How enzymes function threeA human body contains many hundreds of different enzymes found inside cells and as part ofthe d_________ system. Without enzymes, which catalyse the breakdown of nutrients likeproteins, carbohydrates and fats, digestion would be too slow to support all your functions.Like many of the inorganic catalysts, enzymes lower the activation energy and increase the rateof reaction without being used up. With enzymes, the rate of reaction increases as thet___________ increases, doubling for every 10oC rise in temperature. However, aboveapproximately 40oC, enzymes are denatured or destroyed and will stop working altogether.Name three types of enzymes found in the human gut ?Biological enzymes as catalysts: Word bank: digestive temperature How enzymes speed up the rate of reaction Heat sensitive enzymes With inorganic catalyst Substrates with sufficient energy to form new products Rate of reaction With enzyme With enzyme Without enzyme 0 Temp oC 40 60 80 100 A catalyst will lower the activation required for substrates to react As you increase the temperature by 10 oC the with one another to form new products. The graph above shows how rate of reaction doubles until around 40-45 oC by adding a catalyst, the activation energy shifts to the left increasing where the high temperature denatures or the number of successful collisions and therefore increasing the rate of destroys the enzyme. Inorganic catalyst like reaction. Enzymes are highly specific for their substrate. iron and nickel are not temperature sensitive.
  • Science Interactive LTD Copyright 2005Using enzymes as catalystsEnzymes are used in a wide variety of industrial applications. Enzymes found in yeast cells areused for f___________ sugar during alcohol production and making bread. Enzymes found inthe bacteria lactose bacillus are used to produce lactic acid from milk lactose. This is the firststep in the production of cheese and dairy yoghurts. Other enzymes are found in modernbiological w_________ powders that digest stains on clothing. These modern washing powderswork at relatively low temperatures (<40oC) and are energy efficient because you don’t need touse high water temperatures. What temperature would be best to produce cheese from milk ?Biological enzymes as catalysts: Word bank: fermenting washing Alcohol Washing powders Bread manufacture Diagram Notes Yeast is an essential bacteria All biological washing Yeast is used during bread containing enzymes used to powders contain enzymes that making. The carbon dioxide gas ferment sugar from grape, fruit help with the removal of food produced during the respiration or wheat into alcohol. stains. These enzymes digest of wheat sugars and Fermentation of sugar must be and breakdown the stains at carbohydrates cause the bread done in an oxygen free very low temperatures... dough to rise. This gives the environment. below 40 C. o bread its light texture.
  • Science Interactive LTD Copyright 2005Absorption of nutrients by the villiOnce proteins, lipids and carbohydrates are broken down into amino acids, sugars, fatty acids andglycerol, absorption into the blood stream takes place in the small intestine. The small intestine iswell designed for absorption of n___________ into the blood stream. It has a thin lining, larges_________ area and a good blood supply. The surface area of the small intestine is about 10metres squared. To achieve this huge surface area, the small intestine has a folded lining, is verylong and contains millions of tiny microscopic villi. These are finger like projections whichincrease the surface area and help nutrient absorption into the blood.Absorption across the villi into the blood stream: Word bank: nutrients surface Small intestine Features of the small intestine villi (Villi (x 10,000 Magnification))Diagram Fatty acids glycerol Glucose Amino acids Artery Lymph vessel VeinNotes There are many millions of villi found on the surface of the small intestine. They have thin walls and have a very rich blood supply. Amino acids and glucose are absorbed into the blood. Fatty acids and glycerol are absorbed into the lacteal, which then drains into the lymph system.
  • Science Interactive LTD Copyright 2005Breakdown of foods along the digestive tubeThe digestive system is simply a long tube where large nutrient molecules are converted tosmall molecules. In the small intestine, nutrients like g_________ and amino acids are absorbedacross the villi into the hepatic artery. Here they travel to the liver and are either usedimmediately, stored or assimilated into your cells. Look at the overview of digestion and findout where protein, carbohydrate and lipid digestion occurs ?Overview of digestion: Word bank: glucose proteins water Digestive system Key P_______ ? G________ ? Carbohydrate Fatty acids and glycerol Lipids Waste W_______ ? Stool Amino acids Blood cells Hepatic artery to the liver Oesophagus Small intestine Large intestine Rectum Anus Stomach
  • Science Interactive LTD Copyright 2005Assimilation of nutrientsAfter the digestion of proteins, carbohydrates and lipids by the digestive system, g_________and amino acids are absorbed across the villi into the hepatic artery. Here they travel to theliver and are either used immediately, stored or assimilated into your cells. Glucose is eitherrespired or stored in muscle and liver as glycogen. Amino acids are used to build p______ likeenzymes. Excess amino acids are broken down by the liver to form urea. Fatty acids andglycerol, which are absorbed into the lymph system are used to make cell membranes, somehormones or are stored under the skin. What two hormones control the amount of glucose inyour blood stream ? Word bank: glucose proteinsNutrientsystem Small intestine Digestive assimilation: Nutrient use Respiration C6H12O6 6H2O Liver Mitochondria Energy 6O2 6CO2 Cells Blood stream Fat Assimilation Glucose Amino acids Fatty acids & glycerol Glucose Amino acids Fatty acids Muscle
  • Science Interactive LTD Copyright 2005Getting the balance wrong oneA healthy balanced diet should provide you with the right amount of chemical energy,vitamins and minerals. It should also be relatively low in f___ and protein (adult) and highin carbohydrates. Eating too much fatty or sugary foods, low in vitamins and minerals forlong periods of time may lead to health problems later on in life. D______,atherosclerosis, obesity and heart disease are all associated with eating a poor diet. It isestimated that obesity will be the number one killer in the next twenty years in Britain.Consuming the wrong foods: Word bank: fats diabetes Pizza Chips Fast Food Sweets and chocolates Diagram Notes With an ever increasing choice of cheap fatty fast foods, children are now more overweight and less fit when compared to children of the seventies. Obesity, diabetes and in some cases heart disease are now no longer diseases of the old. Children need to avoid ‘junk food’ and eat a more balanced diet containing the right quantities of all of the seven food groups.
  • Science Interactive LTD Copyright 2005Getting the balance wrong twoYour brain regulates your appetite and signals when you are h______. Your body is ableto regulate the amount of chemical energy that you take over many years. Consumingfoods high in sugar and fat and low in bulk tend to upset the right balance. Excesschemical energy in your diet leads to greater assimilation, weight gain and eventuallyobesity. Some individuals who are grossly obese, store upwards of a million additionalkilojoules in their body as f___. What health consequences does obesity in humans cause ?Over consumption of nutrients: Word bank: hungry fat Dietary intake in excess of daily requirements Dietary energy Respiration Diagram Respiration C6H12O6 6H2O Mitochondria Energy Assimilation 6O2 6CO2 Obesity Dietary intake in excess of 10,500 kJ/day (adult male) Notes All the chemical energy, vitamins and minerals that we require are provided by a healthy balanced diet. Overeating or under eating, eating too little vitamins and minerals can cause many health problems in adults and children. It is estimated that one in four adults will be clinically obese by 2010.
  • Science Interactive LTD Copyright 2005Getting the balance wrong threePoverty, drought, disease and war can lead to the failure of crops and livestock. In severe casesof famine, for example the famine in Ethiopia in 1984, millions of people may starve to death.The very old and y_______ are particularly vulnerable. Malnutrition can lead to low bodyweight, weak immune systems and poor development in children. Famine and malnutrition isstill widespread in Africa. Live 8 is now putting pressure on the eight richest countries (G8) toreduce Africa’s debt burden. This should reduce the level of poverty and starvation in Africa.Under consumption of nutrients: Word bank: young Dietary intake below daily requirements Dietary energy Respiration Diagram Respiration C6H12O6 6H2O Mitochondria Energy 6O2 6CO2 Malnutrition Dietary intake below 10,500 kJ/day (adult male) Assimilation Notes Malnutrition in Africa and other developing countries is common place where daily income is less than one pound a day. Many children have less food than they require to live. It is estimated that every three seconds someone dies because of starvation.
  • Science Interactive LTD Copyright 2005Getting the balance right oneOver the last 200 years, here in Western Europe our life expectancy has increased partly due toour healthy diets. Eating a low fat, medium protein, high fibre and carbohydrate diet containinglots of minerals, v________, fresh fruit and vegetables is important so that we maintain ourcorrect b_____ weight. In schools, less junk food and more freshly prepared meals are nowbeing offered to pupils, due to parental pressure and Jamie Oliver, the famous chef who hasbegun to campaign for better school diners.Good lifelong eating habits: Word bank: body weight Dietary intake in excess of daily requirements Diagram Healthy growth and development over your lifetime requires sensible eating and a balanced diet. Respiration Malnutrition Assimilation Dietary intake at 9,750 kJ/day Notes A balanced diet is important for our long life expectancy. Overeating or under eating, eating too little vitamins and minerals can cause many health problems in adults and children. In order to reach your old age, eat a healthy balanced diet...its that simple !
  • Science Interactive LTD Copyright 2005Getting the balance right twoOur dietary intake of foods like p________, carbohydrates and lipids should provide uswith the correct amount of chemical energy to maintain our daily activities, growth (if weare children) and repair. An adult male requires about 10,500 kJ per day, equivalent toabout 100 joules per second. This is the same energy that a 100 watt light bulb uses. Alsoresearch shows, that eating five portions of f____ and vegetables a day reduces the risk ofdeveloping heart disease, colon cancer and obesity. How can you get children to eat morefruit and vegetables ?Healthy diets: Word bank: proteins fruit Steamed potatoes Carrots Fresh fruit Cereals Diagram Notes Eating sufficient quantities of fresh fruit and vegetables helps us avoid many of the lifestyle diseases like obesity, cancer and diabetes. It is recommended that we all eat at least five portions of fruit and vegetables every single day. Fruit and vegetables are an excellent source of all the minerals and vitamins that we require like vitamin C. This helps us to avoid deficiency diseases like scurvy.
  • Science Interactive LTD Copyright 2005Extension questions and homework1: Define the following terms: Physical digestion, Chemical digestion, Enzymes, Excretion, Nutrients, Minerals, Vitamins, Fibre, Absorption, Assimilation & Catalyst.2: Look at the diagram of the three endocrine glands. Complete the table. Roast potatoes Boiled potatoes Fried potatoes Cooking method Healthy option Rich in minerals and vitamins Roasting Boiling Frying3: Answer the following questions: a) The type of teeth we find in an animals mouth can tell us some information on their diet...how. b) What is peristalsis and how does saliva help this process. c) Acid is added to food in the stomach, what is the function of stomach acid. What is the pH of stomach acid. d) Draw a flow chart to show what happens to food as it passes from the mouth to the anus. e) What is the function of bile during the digestion of lipids. Where is it produced. f) What enzyme breaks down carbohydrates to glucose. Where is this enzyme found along the gut. g) What’s the role of the intestine’s villi and where do nutrients travel once they’ve reached the blood stream.
  • Science Interactive LTD Copyright 20054: Look at the information in the table below. Use the following table to answer questions a to d. Person Energy (kJ) Protein (g) Carbohydrate (g) Fats (g) Iron (mg) Vitamin C (mg) Male 10 -12 10800 30 230 45 45 20 Female 10 -12 9700 28 220 39 56 20 Adult male 12900 39 256 54 76 35 Pregnant female 14500 45 260 35 150 40 a) Describe any differences between males and females in children and adults. b) What role do proteins, carbohydrates, fats, vitamin C and iron play in the human body. c) Why does the pregnant female require huge quantities of iron and protein. d) What would a male doing an active job require in kJ/day.5: Answer the following questions: a) Most western diets contain too much fat and salt. What health problems will this cause. b) Why is tooth enamel the hardest substance in the human body. c) What are the four main types of teeth. Is there a relationship between the diet an animal has and the types of teeth they have. d) Which type of teeth are not present in your milk set, but are present in your permanent set. e) What causes tooth decay. Draw three diagram to show the main stages of tooth decay. f) Compare the causes and effects of starvation and overeating in humans. g) What health problems are caused by obesity in humans.
  • Science Interactive LTD Copyright 20056: Look at the information in the table below. Complete the table. Vitamin /mineral Rich food sources Function in the body Deficiency disease A Carrots, milk and dairy products Good eyesight and skin Poor vision and skin C Tissue repair and immune system D Fish oil, dairy and made by body in sunlight Rickets Iron Red meat and liver Calcium Strong teeth and bones Soft bone and teeth7: Answer the following questions: a) Write a paragraph to explain the action of enzymes in digestion. Include the following words: Protease, Amylase, Absorption, Proteins, Carbohydrates, Lipids, Amino-acids, Fatty-acids, Glycerol, Glucose, Blood, Capillaries and Villi. b) What do you think is the main enzyme needed to break down the following foods: Fish, Bread, Butter, Rice, & Chicken. c) Look at the diagram of the digestive system. Match the organs to the following functions: (i) Absorbs water (ii) Contains proteases and acid (iii) Stores faeces (iv) Allows faeces to pass out of the rectum (v) Joins the throat to the stomach (vi) Most absorption of nutrients happens here (vii) Where most food molecules are broken down (viii) down by pancreatic enzymes. (ix) Stores and release bile. Internet: Go to google.co.uk and find how glucose is used by cells during cellular respiration. Cut and paste a diagram to show how cells use sugar during cellular respiration. What are the end products and how are they excreted.