KS4 Biology

1. KS4 Biology Plant Nutrition

2. Contents Plant Nutrition How do plants make food? What is photosynthesis? More about photosynthesis The rate of photosynthesis Minerals from the soil Multiple-choice quiz

3. How do plants get the food they need? All living organisms need food to grow and survive. Plants are known as producers because they provide food for many other organisms. Plants cannot move very much, so how do they get the food that they need?

4. Nutrition in green plants Green plantsareamazing because they actually make their own food! Green plants are the only living organisms that are able to do this. All other organisms rely on plants because of the food that the plants make. What is the name of the process by which plants make their own food?

5. What is photosynthesis? Plants make their own food by photosynthesis. This process is a chemical reaction that uses light energy. light energy The word photosynthesis comes from the Greek language: “photo” means “light” “synthesis” means “putting together” Photosynthesis just means “putting together with light”. What do green plants “put together” to make their food?

6. Contents Plant Nutrition How do plants make food? What is photosynthesis? More about photosynthesis The rate of photosynthesis Minerals from the soil Multiple-choice quiz

7. Photosynthesis: raw materials The raw materials for photosynthesis come from the air and the soil. What are these raw materials called? What else do plants need to turn carbondioxide and waterinto food? carbon dioxide water

8. Photosynthesis: energy for the reaction Photosynthesis is a chemical reaction between carbon dioxide and water. Energy is needed for this reaction to take place. Where do plants get this energy from? light energy carbon dioxide water

9. Photosynthesis: where it happens Plants use light energy from the Sun to power photosynthesis. Where in the leaf does this reaction take place? Photosynthesis takes place in what part of plant cells? light energy carbon dioxide water

10. Photosynthesis: where it happens Photosynthesis takes place in plant cells with chloroplasts. Chloroplasts contain the green chemical called chlorophyll. Chlorophyll absorbs the energy from sunlight that allows carbon dioxide and water to react. What are the products of this reaction? light energy chlorophyll carbon dioxide water

11. Photosynthesis: products of the reaction The products of the reaction between carbon dioxide and water are glucose and oxygen. Which of these products is used by plants? What happens to the ‘waste’ product? light energy chlorophyll carbon dioxide oxygen glucose water

12. Photosynthesis: products of the reaction Glucoseis the useful product for plants. Some glucose is used straightaway by plant cells, some is converted to starch for storage and later used for food. Oxygen is the ‘waste’ product. This gas is transported out of the leaf into the air. Why is this important for humans and other living things? light energy chlorophyll carbon dioxide oxygen oxygen glucose glucose water

13. Photosynthesis: summary Summarize the process of photosynthesis in one sentence. Photosynthesis is a chemical reaction that takes place in the chloroplasts in green plant cells, where light energy is used to convert carbon dioxide and water into glucose and oxygen. Photosynthesis is a chemical reaction which means it can also be summarized in a word equation. What is the word equation for this vital chemical reaction?

14. Photosynthesis:word equation light energy carbon dioxide water glucose oxygen chlorophyll light energy chlorophyll carbon dioxide oxygen glucose water

15. Photosynthesis:word equation activity

16. Photosynthesis: chemical formulae? light energy carbon dioxide water glucose oxygen chlorophyll Photosynthesis is a chemical reaction involving molecules. CO2 H2O C6H12O6 O2 The chemical formula of a glucose molecule is C6H12O6. What are the chemical formulae of the simple molecules that make up carbon dioxide, water and oxygen?

17. Word equation to chemical equation

18. Photosynthesis multiple-choice quiz

19. Contents Plant Nutrition How do plants make food? What isphotosynthesis? More about photosynthesis The rate of photosynthesis Minerals from the soil Multiple-choice quiz

20. Leaves: maximizing photosynthesis Leaves are the most efficient solar panels on Earth! Why can they be called this? Light energy is absorbed by the chlorophyll in leaves and used to carry out photosynthesis. Leaves come in all shapes and sizes but what features do they have in common to maximize photosynthesis?

21. Structure of a leaf How are leaves designed to maximize photosynthesis? Leaves are wide and flat to create a large surface area and to absorb as much light as possible. Leaves are thinso gases can reach cells easily. Leaves have holes, called stomata, on their underside through which gases move in and out. Leaves have lots of veins to carry water to the cells and carry glucose away.

22. Structure of a leaf activity

23. Take a look inside a leaf

24. What happens to the glucose?

25. Testing leaves for starch – procedure

26. Testing leaves for starch – experiment

27. Photosynthesis and respiration light energy carbon dioxide water glucose oxygen chlorophyll glucose oxygen carbon dioxide water Only green plants photosynthesize, but respiration occurs in the cells of all living things to release energy. Photosynthesis (energy needed) Respiration (energy released) Compare the reactants, products and energy results of these two chemical reactions. How are they connected?

28. Photosynthesis and respiration How will the amounts of oxygenandcarbon dioxide in the air vary over 24 hours? amount of oxygen amount of gas in the air amount of carbon dioxide 12a.m. 12p.m. 12a.m. What overall effect do photosynthesis and respiration have on the levels of oxygen and carbon dioxide in the air?

29. Contents Plant Nutrition How do plants make food? What isphotosynthesis? More about photosynthesis The rate of photosynthesis Minerals from the soil Multiple-choice quiz

30. The rate of photosynthesis light energy carbon dioxide water glucose oxygen chlorophyll Photosynthesis is a chemical reaction and so has a rate. Is the rate of photosynthesis always the same? The rate of photosynthesis varies depending on three main factors: light carbon dioxide temperature How do these factors affect the rate of photosynthesis?

31. Light and the rate of photosynthesis light energy carbon dioxide water glucose oxygen chlorophyll Light energy has to be absorbed by chlorophyll for photosynthesis to take place. • The brighter the light, the more light energy there is, • so will photosynthesis be faster or slower? • More light energy means that photosynthesis will be faster. • If light intensity is too high plant cells can be damaged. • How is photosynthesis affected if this happens?

32. Investigating photosynthesis – apparatus

33. Investigating photosynthesis – experiment

34. Investigating photosynthesis – results

35. Carbon dioxide and the rate of photosynthesis light energy carbon dioxide water glucose oxygen chlorophyll Carbon dioxide is one of the raw materials used by plants to make their food. The concentration of carbon dioxide in the air (0.03%) is actually quite low. Why is the concentration of carbon dioxide in commercial greenhouses often raised to about 0.1%? Morecarbon dioxide means more photosynthesis, so plants make more food and grow quicker.

36. Temperature and the rate of photosynthesis light energy carbon dioxide water glucose oxygen chlorophyll Photosynthesis is controlled by enzymes. Enzymes usually work best at warmer temperatures. Why is the rate of photosynthesis slower on a sunny day in winter compared to in summer? If the temperature gets too hot (above 40°C), plant enzymes begin to break down and are destroyed or denatured. Why does photosynthesis stop under such conditions?

37. What is a limiting factor? What is the ideal combination of factors for the maximum rate of photosynthesis? enough light enough carbon dioxide ideal temperature (not too hot or cold) How is the rate affected if one of these factors is restricted? If one of the factors is restricted, the rate of photosynthesis will be below the maximum possible rate. The restricted factor controls how quickly photosynthesis occurs and so limits therate.Itiscalledthelimiting factor.

38. Photosynthesis and light – limiting factors How does the amount of light affect the rate of photosynthesis on this labelled graph? As the amount of light increases, so does the rate. The limiting factor is light. 1 2 Here,increasingtheamount of light has no affect on the rate. The limiting factor is now carbon dioxide or temperature. What must be increased for the rate to increase? 2 rate of photosynthesis 1 light intensity

39. Photosynthesis and carbon dioxide – limiting factors How does the amount of carbon dioxide affect the rate of photosynthesis on this labelled graph? As the amount of carbon dioxide goes up, so does the rate. The limiting factor is carbon dioxide. 1 2 • Here, increasing the amount of carbon dioxide has noaffect on the rate. Light or warmth is now the limiting factor. • What must be increased for the rate to increase? 2 rate of photosynthesis 1 concentration of carbon dioxide

40. Photosynthesis and temperature – limiting factors How does temperature affect the rate of photosynthesis on this labelled graph? • As temperature increases, so does the rate because photosynthetic enzymes work best in the warmth. Here, the limiting factor is temperature. 1 rate of photosynthesis 2 Most plant enzymes are destroyed at about 45°C. Here, photosynthesis stops and the rate falls to zero. What is the limiting factor? 2 1 0oC 45oC temperature

41. Limiting factors activity

42. Limiting factors in the greenhouse

43. Contents Plant Nutrition How do plants make food? What isphotosynthesis? More about photosynthesis The rate of photosynthesis Minerals from the soil Multiple-choice quiz

44. What do plants need for a balanced diet? Plants need carbon dioxide and water for photosynthesis. Do they need any other nutrients to keep healthy? Just like humans, plants need a balanced diet that includes small amounts of mineral elements. What mineral elements do they need?

45. What minerals do plants need? Plants need mineralelementsfor healthy growth. Some of the most important minerals needed by plants are: nitrogen nitrates phosphorus phosphates potassium potassium ions magnesium ions magnesium How do plants obtain these minerals? The mineral elements are found in salts dissolved in water. Plants obtain minerals when they absorb water from the soil. What type of salt are each of these elements found in?

46. What are minerals needed for? How do plants use these mineral elements? making leaves making roots making flowers and fruit making chlorophyll

47. Plant and minerals – summary activity

48. Where do minerals come from? What are the sources of minerals in the soil? Rocks: The minerals in rocks are slowly dissolved by slightly acidic rainwater. These minerals are washed into the soil. Natural fertilizers: Animal faeces and the decay of dead plants and animals return minerals to the soil. Artificial fertilizers: These contain a ready-made mixture of the minerals needed by plants. Why do farmers add fertilizers to their soil?

49. Not enough minerals! What happens if plants do not get enough minerals? Plants do not grow properly if they are deprived of minerals and begin to look unhealthy. If a plant does not get enough of a mineral it is said to have amineral deficiency. Do mineral deficiencies affect a plant in the same way?

50. Mineral deficiency – no nitrogen! Nitrogen is used for making leaves and is probably the most important mineral for plant growth. What is the effectofnitrogen deficiency? upper leaves pale green lower leaves yellow and dead weak stem