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Igcse biology edexcel 2.17 2.32

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Edexcell ppt Biology 2.17-2.32

Used in lessons to scaffold class teaching and as a revision resource for students

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Igcse biology edexcel 2.17 2.32

  1. 1. NUTRITION (Yum Yum Yum)
  2. 2. PLANT NUTRTITION 2.17 describe the process of photosynthesis and understand its importance in the conversion of light energy to chemical energy Nutrition in Plants: Plants are photoautotrophic (i.e. they generate their own “food” using energy from the Sun.) They do this through photosynthesis.
  3. 3. Photosynthesis Equation 2.18 write the word equation and the balanced chemical symbol equation for photosynthesis Nutrition in Flowering Plants: The equation for photosynthesis can be written as: -Word equation -Chemical equation In both cases reaction uses a catalyst (chlorophyll)
  4. 4. Light ….. Glucose….. ? 2.18 write the word equation and the balanced chemical symbol equation for photosynthesis Through photosynthesis light energy is converted into chemical energy in the bonds in glucose. Plants use glucose for the following; 1) Respiration 2) Stored as Starch 3) Turned into Cellulose (cellulose is a polymer of glucose) 4) Used to make fats and oils
  5. 5. Photosynthesis Rate 2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis At any point the rate of photosynthesis can be increased by adding: 1) More CO2 2) More light WAIT!!!! 3) Heating towards optimum temperature This (photosynthesis is not is catalyzed the by whole enzymes). story
  6. 6. Limiting Factors 2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis a)At a certain point the addition of MORE (light & CO2) will not increase the rate of photosynthesis any further. b)This is because a second factor is limiting the rate of photosynthesis. c)Adding more of the rate-limiting factor will increase the rate further until another factor becomes limiting.
  7. 7. Drawing the Graph 2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis The addition of MORE (light & CO2) will not increase the rate of photosynthesis after reaching a rate limiting factor. What about Temperature?
  8. 8. ?Temperature? 2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis
  9. 9. ?Temperature? 2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis Without enough light, a plant cannot photosynthesize very quickly, even if there is plenty of water and carbon dioxide. 1) Increasing the temperature will boost the speed (rate) of photosynthesis. 2) Increasing the intensity will boost the speed (rate) of photosynthesis.
  10. 10. Changing the Limiting Factor 2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis Adding more of the rate-limiting factor increases the rate further…….............until another factor becomes limiting.
  11. 11. What about Water? 2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis Water is not seen as a limiting factor. Plants have enough water in their tissues for photosynthesis. If they do not have enough water the plant will wilt and die anyway. Very sad, but very true.
  12. 12. Leaf Structure 2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis You need to know the parts of the leaf and their adaptations. DO NOT DRAW THIS DIAGRAM
  13. 13. SIMPLE CROSS SECTIONAL LEAF DIAGRAM 2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis
  14. 14. More Complicated Cross Section 2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis
  15. 15. In Real Life 2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis
  16. 16. LABEL 2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis
  17. 17. Adaptation 2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis
  18. 18. Which Tissues Are Missing? 2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis Please add into your notes any tissue missing and write in their functions: 1) Xylem 2) Phloem 3) Vascular Bundle 4) Spongy Mesophyll
  19. 19. Minerals for Nutrition 2.21 understand that plants require mineral ions for growth and that magnesium ions are needed for chlorophyll and nitrate ions are needed for amino acids In addition to water and CO2 plants also need specific minerals; • Nitrate – used to make amino acids for use in plant proteins Magnesium – forms part of the chlorophyll molecule • Potassium - essential for cell membranes • Phosphate - essential part of DNA and cell membranes
  20. 20. Experiment we CAN NOT do!
  21. 21. EXPERIMENTS WE CAN DO 2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll
  22. 22. Using Pond Weed 2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll You must know an experiment that shows how the rate of photosynthesis is affected by rate-limiting factors. Example: Use pond weed (Elodea) which produces bubbles of O2 as it photosynthesizes. 1) The rate of bubble production is proportional to the rate of photosynthesis. 2) When you add light or give it more CO2, the rate of bubble production increases. Watch out:  Cut Elodea underwater or air bubbles will form in xylem  Make sure the O2 is a result of light and not temperature  The examiner may ask for a better way to measure O2 production
  23. 23. Set up for Photosynthesis Rate Vs Light intensity 2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll Change: Light intensity (distance of lamp from Elodea) Measure: Number of bubbles per minute
  24. 24. Setup for Photosynthsis Rate Vs CO2 Concentration 2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll Change: Concentration of Sodium Hydrogen Carbonate Solution (CO2) Measure: Number of bubbles per minute
  25. 25. Testing Photosynthesis by Starch 2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll You need to know an experiment that proves that light and CO2 are essential for the production of starch. A good example is the Geranium plant. It’s leaves normally turn blue-black in the presence of iodine solution showing starch is present (you have to boil it in ethanol first to remove the chlorophyll to show the colour).
  26. 26. Testing Photosynthesis by Starch 2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll Negative Test: Reddish / Brown Positive Test: Blue / Black Safety: Why is it dangerous to boil ethanol directly with a Bunsen Burner instead of using a water bath?
  27. 27. Destarching 2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll You will want to destarch a leaf for this experiment. To remove the starch (destarch) 1) put the poor plant in a dark room for 24 hours. 2) No light means no photosynthesis, no photosynthesis means no glucose produced, no glucose produced means no starch stored in the leaf. Sadly the leaf still needs to respire so it will break all the previously stored starch back into glucose to use in respiration. No more starch, poor leaf…
  28. 28. Destarching 2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll However, if one leaf is put in aluminium foil and another is kept with lime water both do not turn blue-black. Both CO2 and light are essential for starch production and, therefore, essential for photosynthesis.
  29. 29. Nutrition in Humans Syllabus points 2.23 – 2.32
  30. 30. Balanced Diet 2.23 understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre(TA) A diet that contains adequate amounts of all the necessary nutrients required for healthy growth and activity. A balanced diet is one that contains all the ingredients needed for our body to healthily continue its day to day functions in the most efficient way.
  31. 31. Balanced Diet 2.23 understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre(TA)
  32. 32. Balanced Diet 2.23 understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre(TA) 72% of our body is WATER. We contain so much water because water: -Distributes essential nutrients to cells, such as minerals, vitamins and glucose as part of the plasma in our blood -Is an integral part of urine and faeces, which removes waste from our body -Is needed for sweat (sweat is essential in controlling our internal body temperature)
  33. 33. What do you have to eat 2.24 identify sources and describe functions of carbohydrate, protein, lipid (fats and oils), vitamins A, C and D, and the mineral ions calcium and iron, water and dietary fibre as components of the diet Component Function Example of sources Carbohydrate Short-term chemical energy Bread, potatoes Lipids (fats and oils) Long-term chemical energy Bacon, beef Protein Growth & Repair Fish, egg Vitamin A Eyesight Carrots, fish liver oil Vitamin C Healthy skin + gums Oranges Vitamin D Absorb Ca (calcium) Sunlight Mineral ions – Fe (iron) Making haemoglobin in RBC Spinach, animal liver Mineral ions – Ca (calcium) Strong bones and teeth milk Dietary fiber Peristalsis Vegetables, cereal Water Transport system To sweat All chemical reactions occur in solution inside cells Fruits like watermelon
  34. 34. Not all bodies are Energy (J) Equal 2.25 understand that energy requirements vary with activity levels, age and pregnancy (TA) Person Energy needed per day (kJ) Newborn baby 2000 Age 2 5000 Age 6 7500 Gril age 12-14 9000 Boy age 12-14 11000 Girl age 15-17 9000 Boy age 15-17 12000 Female office worker 9500 Male office worker 10500 Heavy manual worker 15000 Pregnant woman 10000 Breast-feeding woman 11300
  35. 35. Not all bodies are Energy (J) Equal 2.25 understand that energy requirements vary with activity levels, age and pregnancy (TA) The two groups that provide energy (through respiration) are lipids and carbohydrates. Per mass lipids have about 10x more energy in them than carbohydrates. The energy in food is measured in Calories (equivalent to 4.2 kJ). If Males need to consume 2500 Calories a day and Females need to consume 2000 Calories a day how many kJ do they need to consume in a day? If: Fat: 1 gram = 9 calories Carbohydrates: 1 gram = 4 calories How many grams of each do you need to supply your energy for the day?
  36. 36. Not all bodies are Energy (J) Equal 2.25 understand that energy requirements vary with activity levels, age and pregnancy (TA) Energy requirements vary according to several factors: • Age: growing people require more energy than others. • Gender: on average, males require more energy than females. • Pregnancy: pregnant women require more energy to nourish themselves and the baby. • Activity levels: more active people require more energy as they use up more energy throughout the day.
  37. 37. Name that structure 2.26 describe the structures of the human alimentary canal and describe the functions of the mouth, oesophagus, stomach, small intestine, large intestine and pancreas game
  38. 38. Describe the function 2.26 describe the structures of the human alimentary canal and describe the functions of the mouth, oesophagus, stomach, small intestine, large intestine and pancreas • Functions Mouth • Physical digestion by teeth • Salivary glands produce saliva  moistens food  making it easier to be swallowed • Chemical digestion by amylase breaks down starch into maltose Oesophagus • Food is moved by peristalsis Stomach • Produces HCl & protease (pepsin) enzymes Small intestine • Produces carbohydrase (maltase), protease (trypsin) & lipase enzymes • Absorbs digested food Large intestine • Absorbs water Pancreas • Produces carbohydrase (maltase), protease (trypsin) & lipase enzymes
  39. 39. Flow Chart the Process 2.27 understand the processes of ingestion, digestion, absorption, assimilation and egestion Ingestion • Taking food into the body Digestion • The breakdown of large insoluble molecules into small soluble molecules so they can be absorbed into the blood Absorption • The process of absorbing nutrients into the body after digestion Assimilation • Using food molecules to build new molecules Egestion • Getting rid of undigested/unwan ted food
  40. 40. Flow Chart the Process 2.27 understand the processes of ingestion, digestion, absorption, assimilation and egestion Digestion can be mechanical or chemical Mechanical Digestion: digestion by physically breaking food into smaller pieces (i.e. not using enzymes). Carried out by; • mouth and teeth chewing food • stomach churning food Chemical Digestion: digestion using enzymes
  41. 41. Peristalsis 2.28 explain how and why food is moved through the gut by peristalsis Food is moved the digestive system by a process known as peristalsis. This is the contractions of two sets of muscles in the walls of the gut. 1) One set runs along the gut 2) The other set circles it. Their wave-like contractions create a squeezing action, moving down the gut. ani
  42. 42. Digestive Enzymes 2.29 understand the role of digestive enzymes, to include the digestion of starch to glucose by amylase and maltase, the digestion of proteins to amino acids by proteases and the digestion of lipids to fatty acids and glycerol by lipases Enzymes and digestion The enzymes involved in respiration, photosynthesis and protein synthesis work inside cells. Other enzymes are produced by specialised cells and released from them these are digestive enzymes. They pass out into the gut, where they catalyse the breakdown of food molecules. Different enzymes (Different enzymes catalyse different digestion reactions) Amylase Starch → sugars Amylase catalyses the breakdown of starch into sugars in the mouth and small intestine Protease Proteins → amino acids Proteases catalyse the breakdown of proteins into amino acids in the stomach and small intestine Lipase Lipids → fatty acids + glycerol Lipases catalyse the breakdown of fats and oils into fatty acids and glycerol in the small intestine
  43. 43. Bile is not so Vile 2.30 understand that bile is produced by the liver and stored in the gall bladder, and understand the role of bile in neutralising stomach acid and emulsifying lipids After the stomach, food travels to the small intestine. The enzymes in the small intestine work best in alkaline conditions, but the food is acidic after being in the stomach. • Bile is alkaline substance • Bile is produced by the liver • Bile is stored in the gall bladder. • Bile is secreted into the small intestine, where it emulsifies fats This is important, because it provides a larger surface area in which the lipases can work.
  44. 44. Silli Villi 2.31 describe the structure of a villus and explain how this helps absorption of the products of digestion in the small intestine The Villus is the location of Absorption of small soluble nutrients into to blood.
  45. 45. How much energy is in that crisp? 2.32 describe an experiment to investigate the energy content in a food sample.(TA) You need to know an experiment that can show how much energy there is in food. Burn a sample of food and use it to heat a fixed volume of water. Record the change in temperature of the water and use the equation below to find out the energy the food gave to the water; Energy = change in temp. x volume of water x 4.2J/g/°C Problem is that not all the food will burn. To control this, you measure the start and end mass of the food and calculate the mass that actually burned. To standardize this, you can divide your calculated energy value by the change in mass to give you the change in mass per gram of food (which will allow you to compare values fairly between different food samples)
  46. 46. How much energy is in that peanut? 2.32 describe an experiment to investigate the energy content in a food sample.(TA) There are problems with using this system: Heat from food item does not heat water Not all the food burns Water looses heat to environment So what is the solution?

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