4.4.1.1 Photosynthetic reaction Word and symbol equation for photosynthesis. Write the word and symbol equation for photosynthesis. Explain why photosynthesis is important for the survival of organisms. Investigate the need for light, carbon dioxide and chlorophyll to make glucose. Explain why plants should be de-starched before photosynthesis experiments and describe how this is done. Describe experiments to show that plants produce oxygen in the light. 1 Collective memory activity for students on leaf structure – self assess. Recap food chains KS3 – draw simple food chains for suggested habitat on whiteboards. Watch BBC video clip to recap how leaves are adapted for photosynthesis. Discuss what plants need to survive and how plants are useful to other organisms in order to come up with the word equation for photosynthesis. Set up experiments or demos. Test leaves in following lesson. Set up a demo to show that plants produce oxygen. Observe results in following lesson. Write word and symbol equations for Put cards in order to create equation. Set up experiments to show that light, carbon dioxide and chlorophyll are needed to make starch – follow up with testing a leaf for starch in later lesson. Consider controls. Predict what will happen and why. Consider how theories develop over time. Cards Photosynthesis experiment: geraniums plants with variegated leaves lamps black paper and paper clips bell jars saturated KOH solution or soda lime. Oxygen demonstration: Elodea/Cabomba glass funnel large beaker test tube.
photosynthesis. Produce cards for equation and put into correct order. Watch BBC video clip about Van Helmont’s experiment. 4.4.1.1 Photosynthetic reaction Word and symbol equations Test to see if a leaf contains starch. Explain why the leaves are tested for starch and not for sugar. Describe the test for oxygen. Interpret results and relate to photosynthesis equation. 1 Test leaves for starch, putting the results for all the different experiments into a table. Use a cut-out to put the steps for the test on a leaf in order, and match a reason for each step. Observe demo set up previous lesson and test gas collected to see if it is oxygen. Discuss how this be used to measure the rate of photosynthesis. Use computer simulation to investigate factors that affect the rate of photosynthesis. out the test and interpret the results. Recall test for oxygen. Interpret results of test and relate to photosynthesis equation. Amend the method to measure rate of photosynthesis. Use a model to embed understanding of process. Oxygen demonstration plants from previous lesson. Leaf test: ethanol boiling tubes beakers rods tiles iodine solution heating apparatus goggles. Oxygen test: splints to test several tubes of the gas collected.
4.4.1.2 Rate of photosynthesis The rate of photosynthesis may be limited by: low temperature shortage of CO2 shortage of light shortage of chlorophyll. Required practical 4: investigate a factor that affects the rate of photosynthesis. State factors that can limit the rate of photosynthesis. Interpret data showing how factors affect the rate of photosynthesis. Required practical: plan a method. 1 Ask students to consider what would happen to a plant if we: put it in the fridge removed CO2 put it in a cupboard took chlorophyll from the leaves. Discuss how the rate of photosynthesis could be measured and consider different methods. Required practical: plan a method. Consider different methods of gathering evidence. Required practical: plan a controlled investigation. Interpret graphs and calculate the rate of photosynthesis. Required practical – see Practical handbook. 4.4.1.2 Required practical: Photosynthesis Investigate the effect of light intensity on the rate of photosynthesis using an aquatic organism such as pondweed. Required practical: carry out an investigation, collect, present and analyse the results. Calculate the rate using numerical information or graphs. 1 Required practical: ask students to identify various factors, select one to control, plan investigation to investigate its effect and explain the procedure and conclusion. Required practical: carry out an investigation, collect, present and analyse the results. Required practical – see Practical handbook. 4.4.1.2 Limiting factors Factors that can the rate of Interpret graphs to decide which factor is limiting the rate. 1 Interpret graphs and explain limiting factors. Plot and interpret data about limiting factors. Mini-greenhouse: plastic food containers
photosynthesis are called limiting factors. Limiting factors are important economically in greenhouses. Explain how conditions in greenhouses can be controlled to optimise the growth of plants. Relate limiting factors to the cost effectiveness of adding heat, light or carbon dioxide to greenhouses, Evaluate the benefits of artificially manipulating the environment in which plants are grown. Design a greenhouse to maintain optimum growth of plants on the moon. Explain all its design features. Compare growth in different areas and relate to photosynthesis. Past paper questions showing data, practise drawing graphs from given data eg QM94R5.09 Debate – are underground or vertical farms the answer to providing food in cities? These are interesting approaches to space saving but how do we ensure the plants get everything they need? Students could design a farm of the future and peer assess. Investigate growth of tomatoes in greenhouse, lab and outside. Use sensors to measure oxygen, light, temperature and carbon dioxide levels. seeds for a faster turnaround. Greenhouses: tomato plants pots compost fertiliser sensors balance. 4.4.1.3 Use of glucose Glucose produced in photosynthesis may be: List ways in which glucose is used by a plant. 1 Use TV show style game format and ask ‘How many daily products come View exhibition of products and suggest where they came from Exhibition of plant products: sugar starchy food protein rich food
Past BL2 exam questions. Animations, images and resources: Video clips: AQA resources: 4.4.2 Respiration Links with 4.1.1.2 – mitochondria, and 4.5.3.7 – adrenaline. Practical sheets available online – Spec ref. Summary of the specification content Learning outcomes What most candidates should be able to do Suggested timing (hours) Opportunities to develop Scientific Communication skills Opportunities to develop and apply practical and enquiry skills Self/peer assessment opportunities and resources Reference to past questions that indicate success
4.4.2.1 Aerobic respiration Respiration can take place aerobically or anaerobically to transfer energy. Respiration is an exothermic reaction. Organisms need energy for chemical reactions, movement and to keep warm. During aerobic respiration glucose and oxygen react to release energy. Word and symbol equation for aerobic respiration. State that all animals and plants produce carbon dioxide and water all the time as a by-product of aerobic respiration. Write the word equation for aerobic respiration. Define the term ‘aerobic’. Describe what organisms need energy for. Describe tests for carbon dioxide and water. the site of aerobic respiration and be able to give examples of cells that contain a lot of mitochondria (links with 4.1.1.2). 2 Show energy drink, glucose tablets and a plant. Discuss substance the body uses as a source of energy and what aerobic means in order to build up the word equation for aerobic respiration. Demonstrate burning food is an exothermic reaction. Watch BBC video clip about respiration. Discuss how to show that humans transfer energy and produce water and carbon dioxide. Relate these observations to the word equation for aerobic respiration. Recap that mitochondria in cells are the site of aerobic respiration (links to 4.1.1.2). Discuss examples of cells that will contain many mitochondria. Consider a bottle of Lucozade, glucose tablets and a plant. Demonstrate the release of energy from food. Investigate inhaled and exhaled air. Demonstrate that animals and plants in the dark respire and release carbon dioxide. Demonstrate that germinating peas/seeds transfer energy as heat. Observe results in following lesson. Observe EM images of mitochondria in different types of cells and make conclusions. Discussion prompts for considering energy release: bottle of Lucozade glucose tablets plant. Demonstration of release of energy: mounted needle or tongs piece of food boiling tube of water thermometer. Video clip: Exhaled air demonstration: carbon dioxide in inhaled and exhaled air apparatus limewater mirrors cobalt chloride paper thermometers.
incomplete oxidation of glucose so less energy is released than in aerobic respiration. Word equation for anaerobic respiration in muscle cells. Word and symbol equation for anaerobic respiration in some plant and yeast cells. Anaerobic respiration in yeast cells is called fermentation and has economic importance in the manufacture of bread and alcoholic drinks. Explain why anaerobic respiration is less efficient than aerobic respiration. the word equation for anaerobic respiration in animal cells. Write the word and symbol equation for anaerobic respiration in yeast cells. State that anaerobic respiration in yeast is called fermentation. Explain why yeast is used to make bread and alcoholic drinks. Interpret data from yeast investigation. Discuss different ways to measure the rate of respiration in yeast cells. Interpret graphs on the rate of respiration in yeast cells. Research how yeast is used to make bread, wine and beer. Investigate the effect of temperature on the rate of respiration in yeast. How does temperature affect the amount bread dough rises? Make bread dough, place set amount in measuring beaker and observe. flasks containing yeast and sugar solution gas syringes. 4.4.2.2 Response to exercise During exercise the heart and breathing Describe and explain the changes that occur in the body during exercise. 1 Mini-practical: start jumps, jog on spot for 1 minute – what do you notice? Why have these changes happened? Investigate the effect of exercise on heart rate, breathing rate, depth of
The oxygen debt is the amount of oxygen needed to oxidise lactic acid. use them as a discussion starter, eg: or 4.4.2.3 Metabolism Metabolism means all the chemical reactions happening in a living organism. Metabolism includes: the conversion of glucose to starch, glycogen and cellulose the formation of lipids the formation of amino-acids and proteins respiration the breakdown of excess proteins Define the term ‘metabolism’. Give examples of reactions in metabolism. Name some chemicals formed from glucose molecules (links to 4.4.1.3). Describe lipid formation from a molecule of glycerol and three molecules of fatty acids. Describe the use of glucose and nitrate ions to form amino acids, which form proteins. Describe the formation of urea. 1 Discuss what metabolism means and examples of the reactions that make up metabolism. Produce a mind map or poster to summarise metabolism and its reactions. Relate this metabolism to other parts of the specification.