A) Need For Food


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A) Need For Food

  1. 1. The Need for Food
  2. 2. Complete the spider diagram to show how the body uses the energy and building blocks we get from food. Discuss Why do we need food? Notes Food ? ? ? ? ?
  3. 3. <ul><li>The three main food groups are …? </li></ul>Carbohydrates Proteins Fats
  4. 4. Activity Ross High Restaurant From the choice of nine food cards on the board select menus of a starter, main course and dessert that will provide: a) the most carbohydrate b) the most protein c) the most fat
  5. 5. Carbohydrates Maltose (soluble) Glucose (soluble) G G G G G G Starch (insoluble) G G G G G G G
  6. 6. Proteins Peptides Amino acids (soluble) Protein (insoluble)
  7. 7. Fats and Oils Fatty Acid Fatty Acid Fatty Acid Glycerol Fat Molecule
  8. 8. Notes Carbohydrates Fats Proteins Elements Present Carbon Hydrogen Oxygen Basic Units Glucose/Maltose molecules Diagram Use Energy/ stored energy Copy and complete the table. Help Torrance p113 Success Guide p33
  9. 9. Food Groups Carbohydrates Fats Proteins Elements Present Carbon Hydrogen Oxygen Carbon Hydrogen Oxygen Carbon Hydrogen Oxygen Nitrogen Basic Units Glucose/Maltose molecules Fatty acids & glycerol Amino Acids Diagram Use Energy/ stored energy Energy Growth and repair
  10. 10. Other Essential Components of a Balanced Diet <ul><li>Minerals </li></ul><ul><li>Vitamins </li></ul><ul><li>Fibre </li></ul><ul><li>Water </li></ul>
  11. 11. Teeth
  12. 12. Different Types of Teeth <ul><li>The numbers and types of teeth an animal has make up its dentition and reflects the animal’s diet . </li></ul><ul><li>There are three main types of dentition </li></ul><ul><li>Omnivore </li></ul><ul><li>Carnivore </li></ul><ul><li>Herbivore </li></ul>Notes
  13. 13. Omnivore Dentition Incisor Canine Premolar Molar
  14. 14. 8 4 8 12 32 Activity Incisor Canine Pre Molar Molar Upper Jaw Lower Jaw Total Incisor Canine Premolar Molar Total 4 4 2 2 4 4 6 6
  15. 15. -Label your copies of the above diagrams. -Colour in the four kinds of teeth for each. Activity Have a look at the skulls and see if you can determine their diet. Notes Help Trying finding help in the class books
  16. 16. <ul><li>Produce a table comparing how omnivores, carnivores and herbivores use each of the four kinds of teeth. </li></ul><ul><li>Answer the questions on page 35 of the Success Guide to form a summary note for teeth. </li></ul>Notes
  17. 17. The Digestive System Use the class text books to label and colour your copy of the diagram. (start labelling in pencil if you are unsure) Notes
  18. 18. Mouth Salivary Gland Liver Stomach Large Intestine Small Intestine Anus Rectum Pancreas Gall Bladder Oesophagus Tongue
  19. 19. Digestion <ul><li>Digestion is the breakdown of large, insoluble molecules into small, soluble molecules by digestive juices. </li></ul><ul><li>The digested food molecules can then be absorbed through the wall of the small intestine into the blood stream . </li></ul>Notes
  20. 20. Digestive Enzymes <ul><li>Most digestive juices contain enzymes. </li></ul><ul><li>There are groups of enzymes involved in digestion. </li></ul><ul><li>Each group acts on a different type of food, called the substrate. </li></ul><ul><li>The substrate gets broken down by enzymes to substances called products. </li></ul>Notes
  21. 21. <ul><li>Work in groups of three. </li></ul><ul><li>Safety glasses on at all times. </li></ul><ul><li>Investigate one enzyme each and share the results with your group. </li></ul>Experiment
  22. 22. Results Write a conclusion for each of the enzymes stating which enzyme group they belong to. Yes/No EnzymeA Starch Digested EnzymeB Protein Digested EnzymeC Fat Digested
  23. 23. Now that we have labelled the organs of the digestive system and investigated enzyme groups… Produce a table showing the function of all the organs in the digestive system. Notes Help Success Guide p38 Torrance p121/122
  24. 24. Need a Hint? -If a marble was stuck in a hose pipe what would you do to get it out? -What tissue do you think we have in the digestive system that would cause the same effect? Discuss How does food work its way through all the tubes in the digestive tract?
  25. 25. Peristalsis <ul><li>The action of peristalsis takes place along the whole length of the gut from mouth to anus. Its purpose is to move food through the gut. </li></ul>Notes
  26. 26. Mechanism for Peristalsis Layers of muscle Contraction of muscle Relaxation of muscle Direction of movement Notes
  27. 27. Click on the image below to watch the Yakult TV ad: What does ‘planet you’ look like? Why does ‘planet you’ look like this?
  28. 28. The Small Intestine <ul><li>The main function of the small intestine is to absorb the products of digestion. </li></ul><ul><li>The small intestine is very efficient at this job because of its structure. </li></ul>Make notes explaining the features the small intestine has that make it suited to its job. Notes
  29. 29. Villi are finger like folds in the surface of the small intestine Villi
  30. 30. The Small Intestine – The Villi Thin epithelium Blood capillary Tiny lymphatic vessel Enzyme secreting gland - Glucose and amino acids are transported in the blood stream. - Fats are transported in the lacteal.
  31. 31. The Model Gut Experiment
  32. 32. The Large Intestine <ul><li>Any material that is not digested, plus bacteria, dead cells and water pass along the small intestine into the large intestine. </li></ul><ul><li>In the large intestine water is reabsorbed back into the body. </li></ul><ul><li>The material that is left is called faeces, which is stored in the rectum, before being excreted through the anus. </li></ul>
  33. 33. Large Intestine By this point only indigestible material and water remains. The large intestine absorbs water and remaining material is excreted as faeces.
  34. 34. Digestive System
  35. 35. Check Test 1 mark 3 marks 3 marks 1 mark Q1 Type of Food Carbohydrate a) b) Chemical Elements Carbon c) d) Hydrogen e) f) Nitrogen g) h) i) Basic Units j) k) l) Function m) Source of energy/ insulation n)
  36. 36. Q2 Which of the following statements is true about digestion? <ul><li>It converts sugar into starch which can be absorbed into the blood. </li></ul><ul><li>It breaks down large molecules into smaller ones that can pass through the wall of the gut. </li></ul><ul><li>It converts proteins to amino acids for storage in the stomach. </li></ul>1 mark
  37. 37. <ul><li>Q3 </li></ul><ul><li>Write True or False for the following statements. </li></ul><ul><li>Human teeth are specialised to cope with a varied diet. </li></ul><ul><li>Sheep have no canines in the upper jaw. </li></ul><ul><li>Sheep molars have smooth rounded surfaces for grinding grass. </li></ul><ul><li>Dogs have a pad on the upper jaw to remove flesh from bone. </li></ul><ul><li>A wolves canines are long and pointed for piercing and gripping. </li></ul><ul><li>Dogs use their premolars and molars for slicing flesh. </li></ul>6 marks
  38. 38. a) b) d) e) c) 3 marks Q4
  39. 39. Q5 Describe the role of the stomach in digestion. 1 mark Q6 Describe how peristalsis pushes food through the digestive system. 1 mark
  40. 40. <ul><li>Q7 </li></ul><ul><li>The digestion of carbohydrates, proteins and fats is carried out by </li></ul><ul><li>An enzyme which slows down the process. </li></ul><ul><li>One enzyme that breaks down all three types of food. </li></ul><ul><li>An acid which speeds up the process. </li></ul><ul><li>A different enzyme for each type of food. </li></ul>1 mark
  41. 41. Q8 Give two features of the small intestine which make it efficient for absorption. 2 marks Q9 Which part of the digestion system is the site where most water is removed from the contents. 1 mark
  42. 42. Homework Starting tomorrow, record everything you have to drink in a day. Have a separate record sheet for each day and keep recording till next time you are in Biology. Record volumes if possible, if not record if you used a mug/ cup / carton etc.