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Nutrition

Nutrition. Biology. Learning Outcome 1. Explain in simple terms why food is required by animals. You are what you eat!!. In this lesson you will Look at what is a balanced diet Carry out food tests on Starch Glucose Protein Fat Discuss what happens if you don’t eat a balanced diet.

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Nutrition

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  1. Nutrition Biology

  2. Learning Outcome 1 • Explain in simple terms why food is required by animals.

  3. You are what you eat!! • In this lesson you will • Look at what is a balanced diet • Carry out food tests on • Starch • Glucose • Protein • Fat • Discuss what happens if you don’t eat a balanced diet

  4. Balanced Diet

  5. What is a balanced diet? • Your diet must include all groups of food substances • Carbohydrates, fats, proteins, minerals and vitamins • It must also include water and fibre. • A balanced diet is a diet that provides enough of these substances in the correct proportions to keep you healthy.

  6. Carbohydrates • Carbohydrates give us energy. • Chemical elements – C, H and O. • Starch is made from simple sugars called glucose

  7. Testing for glucose • Pour some glucose solution into a test tube • Add a few drops of benedict's solution • Heat in a water bath

  8. Testing For Starch • Put a few drops of starch solution on a spotting tile. • Add a few drops of iodine.

  9. Proteins • Proteins are needed for growth and repair. • Proteins are made from amino acids • Chemical elements – C, H, O, N

  10. Testing for Proteins • Put 2 ml of protein solution in a test tube • Add 2ml of Biurets reagent

  11. Fats • Fats are an energy store, protecting vital organs and providing insulation. • Fats contain C, H and O • Fats are made from a glycerol molecule and three fatty acids.

  12. Testing for fat (the emulsion test) • Add a few drops of cooking oil into a test tube • Add 2cm3 ethanol and shake • Add 2cm3 water and shake again.

  13. Nutrients

  14. Learning Outcomes • list the chemical elements that make up: • carbohydrates • fats • Proteins • Describe the synthesis of large molecules from smaller basic units • list the principal sources of, and describe the importance of carbohydrates, fats, proteins,.

  15. Quick Revision • A balanced diet must contain all the essential nutrients in the correct amounts and proportions. • The nutrients needed are • Carbohydrate • Fat • Protein • Vitamins • Minerals • Fibre • Water.

  16. Main Nutrients

  17. What you really need to remember!! • Carbohydrates, fats and proteins are all made up of the elements carbon, hydrogen and oxygen • Proteins always contain nitrogen and sometimes sulphur • One way to remember this is • Carb O Hydrate

  18. Carbohydrates • Large carbohydrates molecules such as starch and glycogen are made up of long chains of smaller units, e.g. monosaccharides (glucose), which are held together by chemical bonds

  19. Fats • Fats are made up of three fatty acids and a glycerol

  20. Proteins • Proteins are made up of long chains of amino acids

  21. Food Tests • What is the test for starch? • What is the test for glucose? • What is the test for protein? • What is the test for fats? • What does a positive result look like?

  22. Learning Outcomes • list the principal sources of, and describe the importance of: • vitamins (C and D only) • mineral salts (calcium and iron only) • fibre (roughage) • water • describe the deficiency symptoms for: • vitamins (C and D only) • mineral salts (calcium and iron only)

  23. Vitamin C • Function • Maintain healthy skin and gums • Good Food Source • Citrus fruits, black currants, cabbage, tomato, guava, mango • Effect of deficiency • Scurvy • Bleeding under skin • Bleeding gums

  24. Vitamin D • Function • Needed to maintain hard bones • Helps absorb calcium from small intestine • Good Food Source • Milk, cheese, egg yolk, fish liver oil • Made in skin when exposed to sunlight • Effect of deficiency • rickets

  25. Calcium • Function • Healthy teeth and bones • Normal blood clotting • Good Food Source • Milk, cheese, fish • Effect of deficiency • Rickets • Slow blood clotting

  26. Iron • Function • Formation of haemoglobin in red blood cells • Good Food Source • Red meat, liver, kidney, eggs, green vegetables (spinach), chocolate • Effect of deficiency • Anaemia • Constant tiredness • Lack of energy

  27. Fibre • Function • This is cellulose which we can not digest • It adds bulk to the undigested food in the intestines, maintaining peristalsis • Good Food Source • Vegetables, fruit, wholemeal bread • Effect of deficiency • Constipation • Long term deficiency may lead to bowel cancer

  28. Water • Function • Formation of blood, cytoplasm • Solvent for transport of nutrients and removal of waste • Enzymes only work in solution • Good Food Source • Drinks, fruits, vegetables • Effect of deficiency • dehydration

  29. Pupil activity • Design a mind map to summarise the information you have been taught so far on Nutrients.

  30. Learning Outcomes • understand the concept of a balanced diet • describe: • a balanced diet related to age, sex and activity of an individual • the effects of malnutrition in relation to starvation, coronary heart disease, constipation and obesity

  31. What happens if you don’t eat a balanced diet. What is this cartoon trying to demonstrate? Can you think of any examples of health problems that arise from not eating a balanced diet? Give three examples and explain the effects on health.

  32. Dietary requirements • Adequate diet • Provides sufficient energy for the performance of metabolic work • Balance diet • Provides all the dietary requirements in the correct proportions • 1/7 fat • 1/7 protein • 5/7 carbohydrate

  33. Dietary requirements • Energy is provided by fat and carbohydrate intake • Dietary requirements depend on • Age • Energy demand increases until we stop growing • Sex • Males use up more energy than females • Activity • Physical work will use up more energy than office work.

  34. An Unbalanced dietMalnutrition • An unbalanced diet could lead to • Obesity • Risks include coronary heart disease and diabetes • Too much animal fat can lead to high cholesterol • Risks include coronary heart disease and angina • Lack of protein in diet can lead to kwashiorkor • Lack of fibre can lead to constipation and bowel cancer • Vitamin and mineral deficiencies

  35. teeth • There are different types of teeth, each specially shaped to perform a particular job. • Incisor • A broad flat sharp tooth found at the front of the mouth. Designed for biting and cutting food. • Canine • A sharp pointed tooth for piercing flesh and tearing. • Pre-molar & molar • A broad flat tooth with many cusps. Its rough surface is used for crushing, grinding and chewing food

  36. Colour in your diagram of the tooth, Colour in the positions of the different types of teeth in the human jaw Structure of a tooth

  37. Structure of a tooth enamel crown dentine gum Pulp cavity root cement

  38. Causes of dental decay • Bacteria and food deposits form plaque • Bacteria feed on sugars and produce acid • Acid dissolves the enamel forming a hole • Dentine dissolves more rapidly • If hole reaches pulp cavity can lead to bacterial infection, toothache and abscess

  39. Proper care of teeth • Avoid sugary foods • Use dental floss or a tooth pick • Use a fluoride toothpaste • Visit dentist regularly

  40. Fluoride • Growing children absorb fluoride from their diet • It becomes part of enamel of developing teeth • Enamel becomes more resistant to tooth decay

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