Presentation is loading. Please wait.

Presentation is loading. Please wait.

© Boardworks Ltd 2004 1 of 57 KS4 Biology Plant Nutrition.

Similar presentations


Presentation on theme: "© Boardworks Ltd 2004 1 of 57 KS4 Biology Plant Nutrition."— Presentation transcript:

1 © Boardworks Ltd of 57 KS4 Biology Plant Nutrition

2 © Boardworks Ltd of 57 The rate of photosynthesis Minerals from the soil Plant Nutrition What is photosynthesis? More about photosynthesis Contents How do plants make food? Multiple-choice quiz

3 © Boardworks Ltd of 57 All living organisms need food to grow and survive. How do plants get the food they need? 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 © Boardworks Ltd of 57 Green plants are amazing 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? Nutrition in green plants

5 © Boardworks Ltd of 57 Plants make their own food by photosynthesis. This process is a chemical reaction that uses light energy. What is photosynthesis? 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 © Boardworks Ltd of 57 The rate of photosynthesis Minerals from the soil Plant Nutrition What is photosynthesis? More about photosynthesis Contents How do plants make food? Multiple-choice quiz

7 © Boardworks Ltd of 57 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 carbon dioxide and water into food? Photosynthesis: raw materials carbon dioxide water

8 © Boardworks Ltd of 57 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? Photosynthesis: energy for the reaction carbon dioxide water light energy

9 © Boardworks Ltd of 57 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? Photosynthesis: where it happens carbon dioxide water light energy

10 © Boardworks Ltd of 57 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? Photosynthesis: where it happens carbon dioxide water light energy chlorophyll

11 © Boardworks Ltd of 57 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? Photosynthesis: products of the reaction carbon dioxide water glucose oxygen light energy chlorophyll

12 © Boardworks Ltd of 57 Glucose is 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? Photosynthesis: products of the reaction carbon dioxide water oxygen light energy chlorophyll glucose oxygen glucose

13 © Boardworks Ltd of 57 Photosynthesis: summary Summarize the process of photosynthesis in one sentence. 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? 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.

14 © Boardworks Ltd of 57 Photosynthesis: word equation carbon dioxide water oxygen light energy chlorophyll glucose light energy chlorophyll carbon dioxide wateroxygen

15 © Boardworks Ltd of 57 Photosynthesis: word equation activity

16 © Boardworks Ltd of 57 Photosynthesis: chemical formulae? Photosynthesis is a chemical reaction involving molecules. glucose light energy chlorophyll carbon dioxide wateroxygen CO 2 H2OH2OO2O2 C 6 H 12 O 6 The chemical formula of a glucose molecule is C 6 H 12 O 6. What are the chemical formulae of the simple molecules that make up carbon dioxide, water and oxygen?

17 © Boardworks Ltd of 57 Word equation to chemical equation

18 © Boardworks Ltd of 57 Photosynthesis multiple-choice quiz

19 © Boardworks Ltd of 57 The rate of photosynthesis Minerals from the soil Plant Nutrition What is photosynthesis? More about photosynthesis Contents How do plants make food? Multiple-choice quiz

20 © Boardworks Ltd of 57 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 © Boardworks Ltd of 57 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 thin so 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 © Boardworks Ltd of 57 Structure of a leaf activity

23 © Boardworks Ltd of 57 Take a look inside a leaf

24 © Boardworks Ltd of 57 What happens to the glucose?

25 © Boardworks Ltd of 57 Testing leaves for starch – procedure

26 © Boardworks Ltd of 57 Testing leaves for starch – experiment

27 © Boardworks Ltd of 57 Photosynthesis and respiration Only green plants photosynthesize, glucose light energy chlorophyll carbon dioxide wateroxygen Compare the reactants, products and energy results of these two chemical reactions. How are they connected? carbon dioxide glucose oxygenwater Photosynthesis Respiration but respiration occurs in the cells of all living things to release energy. (energy needed) (energy released)

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

29 © Boardworks Ltd of 57 The rate of photosynthesis Minerals from the soil Plant Nutrition What is photosynthesis? More about photosynthesis Contents How do plants make food? Multiple-choice quiz

30 © Boardworks Ltd of 57 Photosynthesis is a chemical reaction and so has a rate. Is the rate of photosynthesis always the same? The rate of photosynthesis light glucose light energy chlorophyll carbon dioxide wateroxygen The rate of photosynthesis varies depending on three main factors: How do these factors affect the rate of photosynthesis? carbon dioxide temperature

31 © Boardworks Ltd of 57 Light and the rate of photosynthesis Light energy has to be absorbed by chlorophyll for photosynthesis to take place. glucose light energy chlorophyll carbon dioxide wateroxygen 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 © Boardworks Ltd of 57 Investigating photosynthesis – apparatus

33 © Boardworks Ltd of 57 Investigating photosynthesis – experiment

34 © Boardworks Ltd of 57 Investigating photosynthesis – results

35 © Boardworks Ltd of 57 Carbon dioxide is one of the raw materials used by plants to make their food. Carbon dioxide and the rate of photosynthesis glucose light energy chlorophyll carbon dioxide wateroxygen 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%? More carbon dioxide means more photosynthesis, so plants make more food and grow quicker.

36 © Boardworks Ltd of 57 Photosynthesis is controlled by enzymes. Enzymes usually work best at warmer temperatures. Temperature and the rate of photosynthesis glucose light energy chlorophyll carbon dioxide wateroxygen 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 © Boardworks Ltd of 57 What is the ideal combination of factors for the maximum rate of photosynthesis? What is a limiting factor? 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 the rate. It is called the limiting factor.

38 © Boardworks Ltd of 57 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. light intensity rate of photosynthesis Here, increasing the amount 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?

39 © Boardworks Ltd of 57 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. concentration of carbon dioxide rate of photosynthesis Here, increasing the amount of carbon dioxide has no affect on the rate. Light or warmth is now the limiting factor. What must be increased for the rate to increase?

40 © Boardworks Ltd of 57 Photosynthesis and temperature – limiting factors How does temperature affect the rate of photosynthesis on this labelled graph? 1.As temperature increases, so does the rate because photosynthetic enzymes work best in the warmth. Here, the limiting factor is temperature. temperature rate of photosynthesis 0oC0oC45 o C Most plant enzymes are destroyed at about 45°C. Here, photosynthesis stops and the rate falls to zero. What is the limiting factor?

41 © Boardworks Ltd of 57 Limiting factors activity

42 © Boardworks Ltd of 57 Limiting factors in the greenhouse

43 © Boardworks Ltd of 57 The rate of photosynthesis Minerals from the soil Plant Nutrition What is photosynthesis? More about photosynthesis Contents How do plants make food? Multiple-choice quiz

44 © Boardworks Ltd of 57 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 © Boardworks Ltd of 57 What minerals do plants need? Plants need mineral elements for healthy growth. Some of the most important minerals needed by plants are: The mineral elements are found in salts dissolved in water. Plants obtain minerals when they absorb water from the soil. How do plants obtain these minerals? nitrogen potassium ions phosphorus potassium magnesium magnesium ions phosphates nitrates What type of salt are each of these elements found in?

46 © Boardworks Ltd of 57 What are minerals needed for? How do plants use these mineral elements? Mineral elementHow mineral is used in plants nitrogen (N) phosphorus (P) potassium (K) magnesium (Mg) making leaves making roots making flowers and fruit making chlorophyll

47 © Boardworks Ltd of 57 Plant and minerals – summary activity

48 © Boardworks Ltd of 57 Where do minerals come from? 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. What are the sources of minerals in the soil? Why do farmers add fertilizers to their soil?

49 © Boardworks Ltd of 57 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 a mineral deficiency. Do mineral deficiencies affect a plant in the same way?

50 © Boardworks Ltd of 57 Mineral deficiency – no nitrogen! Nitrogen is used for making leaves and is probably the most important mineral for plant growth. What is the effect of nitrogen deficiency ? lower leaves yellow and dead weak stem upper leaves pale green

51 © Boardworks Ltd of 57 Mineral deficiency – no phosphorus! Phosphorus is used for making roots and is important for all the other minerals used by plants. What is the effect of phosphorus deficiency? small roots purple leaves

52 © Boardworks Ltd of 57 Mineral deficiency – no potassium! Potassium is used for making flowers and fruit, so crops are given extra potassium before they start to fruit. What is the effect of potassium deficiency? poor flower and fruit growth yellow leaves with dead spots

53 © Boardworks Ltd of 57 Mineral deficiency – no magnesium! Magnesium is used for making chlorophyll and so is vital for the process of photosynthesis. What is the effect of magnesium deficiency? upper leaves normal (leaves turn yellow from bottom upwards) lower leaves pale green or yellow

54 © Boardworks Ltd of 57 Mineral deficiency experiment

55 © Boardworks Ltd of 57 Plant and minerals summary MineralUse in plantDeficiency signs nitrogen phosphorus potassium magnesium Complete this table of plant mineral needs and deficiencies. making leaves making roots making flowers and fruits making chlorophyll stunted growth and yellow leaves poor roots and purple leaves yellow leaves with dead spots leaves turn yellow from the bottom

56 © Boardworks Ltd of 57 The rate of photosynthesis Minerals from the soil Plant Nutrition What is photosynthesis? More about photosynthesis Contents How do plants make food? Multiple-choice quiz

57 © Boardworks Ltd of 57 Multiple-choice quiz


Download ppt "© Boardworks Ltd 2004 1 of 57 KS4 Biology Plant Nutrition."

Similar presentations


Ads by Google