4.2 Transport over larger distances 4.2.1 Systems in the human body 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 apply practical and enquiry skills Self/peer assessment Opportunities and resources Reference to past questions that indicate success 4.2.1.1 Respiration in cells can take place aerobically (using oxygen) or anaerobically (without oxygen). Aerobic respiration is an exothermic reaction represented by word and symbol equations. glucose + oxygen carbon → dioxide + water An exothermic reaction is one that transfers energy to its surroundings. Organisms need energy for: Chemical reactions to build larger molecules Movement Keeping warm. 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. State the site of aerobic respiration and be able to give examples of cells that contain a lot of 1 Show energy 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. that mitochondria in cells are the site of aerobic respiration (links to 4.1.3.2). Consider a bottle of Lucozade, glucose tablets and a 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 Demonstration of release of energy: mounted needle or tongs of food boiling tube of water thermometer. clip: Exhaled air demonstration:
mitochondria (links with 4.1.3.2). Define the term ‘metabolism’. Give examples of reactions in metabolism. Discuss examples of that will contain many mitochondria. Discuss what metabolism means and examples of the reactions that make up metabolism. Does energy transfer between cells? Students research the role of ATP in energy transfer and link to mitochondria. Show diagrams of 'classic' experiments, eg mouse in bell jar with or without a green plant, with sufficient annotations to enable students to deduce the rationale and findings of the investigations. carbon dioxide in inhaled and exhaled air apparatus limewater mirrors cobalt chloride paper thermometers. Demonstrating evidence of respiration in an animal: two bell jars connected to two containers of limewater that air is passing through via tubes (first container is fitted with thistle funnel containing soda lime)
pump to draw air through system small animal black paper. Demonstrating energy transfers as heat: soaked peas/ seeds boiled and cooled peas thermos flasks with temperature probes. 4.2.1.1 cont. Anaerobic respiration in muscles is also exothermic but it gives out less energy. It is represented by the word equation: glucose → lactic acid Because the oxidation of glucose is incomplete in anaerobic respiration much Define the term ‘anaerobic’. Explain why anaerobic respiration is less efficient than aerobic respiration. the word equation for 1 Mini-practical: star jumps, jog on spot for 1 minute – what do you notice? Why have these changes happened? Plan an investigation the effects of exercise on the body. Interpret line graphs and spirometer tracings to Investigate the effect of exercise on heart rate, breathing rate, depth of breathing and temperature. Investigate effect of muscle fatigue on muscle strength and Timer, pulse sensor and spirometer if available. Muscle strength meters. Timers and masses.
less energy is given out than in aerobic respiration. If insufficient oxygen is supplied, anaerobic respiration takes place in muscles. The incomplete oxidation of glucose causes a buildup of lactic acid and creates an oxygen debt. Oxygen debt is the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells. anaerobic respiration in animal cells. Describe and explain the changes that occur in the body during exercise. Design and carry out an investigation about the effects of exercise on the body. Present and interpret data heart rate, breathing rate and breath volume. Interpret data relating to the effects of exercise on the body, eg spirometer tracings. Describe the effects of long periods of vigorous exercise on the body. Define the term ‘oxygen debt’. compare rate of breathing before, during and after exercise. Use spirometer tracings to calculate breathing rate and depth of breathing. Interpret data on heart rate, temperature and depth of breathing during exercise. Interpret data to compare how fit different people are. Discuss causes and effects of muscle fatigue and relate these to lactic acid build up. a video showing sprinters and discuss how the body reacts at the end of the race – paying back the oxygen debt. YouTube has a variety of videos of marathon runners struggling over the finish line – use them as a discussion starter, eg: produce an article for a fitness magazine. Investigate how long it takes muscles to fatigue – repetitive actions, eg step ups, holding masses at arm’s length or holding arm aloft and opening/closing fingers rapidly. Interpret spirometer traces. Calculate breathing rate and of breathing. Interpret data and draw conclusions. Show graphs of lactic acid concentration and speed or fitness. Students relate the data to the lesson and give a reasoned explanation. AQA resources:
having a surface area a membrane that is thin, to provide a short diffusion path (in animals) having an efficient blood supply (in animals, for gaseous exchange) being ventilated. ratio. Describe overall trends. Discuss implications for diffusion and how a circulatory/transport system enables larger organisms to develop. Use graphs to estimate other SA:volume ratios. MS 1c Calculate and compare surface area:volume ratios. 4.2.1.3 The heart is a muscular organ that pumps blood around the body in a dual circulatory system. The ventricle pumps blood to the lungs where gas exchange takes place. The left ventricle pumps blood around the rest of the body. Valves prevent the from flowing back from the Describe the functions of the heart and circulatory system Describe and label a diagram of the heart showing four chambers, vena cava, pulmonary artery, pulmonary vein and aorta. 3 Describe the functions of the heart and circulatory system. Show pictures of a single and a double circulatory system. Students write down similarities and differences. Discuss the reasons why. Use computer simulation to show the flow of blood around the heart, lungs and body. Students model the circulatory system. Demo: show a model heart and identify the chambers, main blood vessels and valves. Demo: Heart and lungs of a pig to show the associated vessels. Allow students to feel the vessels. Show students how to dissect their pig hearts and identify the vessels. Model heart Teachit Science resources Demo: heart and lungs of pig with vessels attached, board, scissors, mounted needle, gloves. Dissection: hearts with vessels attached, boards,
ventricles to the atria. Knowledge of the names of the heart valves is not required. Blood vessels associated with the heart include the aorta, vena cava, pulmonary artery, pulmonary vein and coronary arteries. Gas exchange place in the lungs. Important features of the lungs are the trachea, bronchi, alveoli and the capillary network surrounding the alveoli. The alveoli have the specialised surfaces for gas exchange between air and the blood. The natural resting rate is controlled by a group of cells that act as a pacemaker, located in the right atrium. Artificial pacemakers are electrical devices used to correct Describe the flow of from the body, through the heart and lungs and back to the body. Explain how the is adapted for its function. Describe the heart as a double pump and explain why this is efficient. Explain how the alveoli are adapted for efficient gas exchange. Explain how the blood vessels are adapted for their function. Label a diagram of the heart and colour to show oxygenated and deoxygenated blood. Describe the flow of blood by sorting cards with names of blood vessels, chambers, lungs and body to show direction of blood flow. Research the work of and William Harvey and produce a report. Recap KS3 work on the structure and function of the gas exchange system. Use a model and identify the main organs in the gas exchange system. Label a diagram of the gas exchange system. Label a diagram of the alveoli and explain how they are adapted for efficient gas exchange. Use computer simulation or video clip showing the three Dissect a pig’s heart. See Nuffield Foundation Practical Science suggestions. Show lungs and trachea of a sheep from a local butcher. Identify the main structures and discuss the roles. Inflate the lungs with a bicycle pump. Observe prepared slides of the different vessels, or use Compare their size and structure. Students compare three types of blood vessel in a Venn diagram or similar. Measure pulse rate and blood pressure – lying down, sitting and standing. scissors, mounted needles, gloves. (video clip showing heart and pacemaker cells). Torso or model of gas exchange system. Sheep lungs and trachea (PLUCK), bicycle pump Microscopes, prepared slides, Pulse and blood pressure: timers or pulse rate sensor, blood pressure monitor.
red blood cells blood cells platelets Explain how each component is adapted for its function. Identify pictures of the different blood cells. Draw and label diagrams of red blood cells, white blood cells and platelets. Students list the substances dissolved in plasma. How may these change over time? BBC lesson about blood with animations (see resources). Produce models of red blood cells, white blood cells and platelets. Produce a Mind map to explain the composition of blood and describe the functions of plasma, red blood cells, white blood cells and platelets. Write a word equation for the reaction of oxygen with haemoglobin. size and number of red and white blood cells. Given data, students construct a diagram showing the percentage of each main component of blood. 4.2.1.5 The digestive system uses enzymes to break down large molecules in food into small soluble molecules that can be absorbed into the Describe the functions of the digestive system to 2 Required practical 7: use qualitative reagents to test for a range of carbohydrates, lipids and proteins. To include: Benedict’s test for Demonstrate the digestion show: mouth is potato masher in a bowl Model of the digestive system and organs.
blood through the walls of the gut. The blood carries the small molecules to the cells of the body where they can be used for respiration or to make the new large molecules that the cells need as reserves of energy or for growth and repair. Starch is a carbohydrate. Its molecules consist of a long chain of glucose molecules. Digestion by carbohydrase enzymes breaks down insoluble starch to glucose. Cells use glucose during respiration. Lipids are fats and oils. Digestion by lipase enzymes breaks down lipids to glycerol and fatty acids. Cells reform fats from the fatty acids and glycerol molecules. Fats are stored as a source of energy because cells can break digest and absorb foods. Identify the positions of the main organs on a diagram of the digestive system. Know that food molecules must be small and soluble in order to be absorbed into the blood. Describe how amino acids are broken down in the liver to form urea for excretion by the kidneys as urine. sugars, iodine test for starch and Biuret reagent for protein. Biology AT 2. Recap the functions of the digestive system, and organs in the system from KS3. Label a diagram of the digestive system and colour areas where digestion, digestion and absorption of food and absorption of water occur. Watch the video of digestion of an egg sandwich (see resources). Describe the pathway of an egg sandwich from mouth to anus. Tell it as a story. Links to 4.7.4.7 Enzymes Students design a game to aid learning. They should include: nutrient, structure and function, digestive enzyme, product. (add food and mash). Squirt in saliva transfer into a sandwich bag (stomach) and squeeze with ‘enzymes’ transfer into another bowl via a sieve (small intestine) what is left in the must be soaked up with a sponge (large intestine) then emptied into a small sandwich bag (rectum) cut a hole in corner of bag for anus and show egestion View sections of the small intestine under a microscope Two bowls Masher Food Bottle of ‘saliva’ and ‘enzymes’ Sieve Two sandwich bags Scissors Microscopes Slides of small intestine. Teachit Science resource
them down and use them in respiration. Proteins are molecules made up of many amino acids linked together. Digestion by protease enzymes breaks down proteins to amino acids. Cells use amino acids to make new proteins. The liver breaks down unwanted amino acids to urea, which is then carried by the blood to the kidneys. The kidneys excrete urea in solution as urine. Make connections between products of digestion and other organ systems. Students research diets. Calculate the % difference between RDA (g/kg) of protein and (g/kg) intake in a high-protein diet. Some researchers have expressed concerns that a high-protein diet may cause kidney damage. How might this be? Make a model to show how the villi increase the surface area of the small intestine. Use play to model structure of three key nutrients. Students research a topical issue connected to dietary advice, eg sugar in diet, Omega-3, cholesterol, antioxidants, 'super foods'. Can they find quantitative data to support claims? How do cells make new proteins? Students use the particle model to explain the process of digestion and absorption. 4.2.1.6 The nervous system enables humans to react to Explain the importance of being able to respond to 2–3 Starter: any clip that has a ‘surprise’. Plan and manage a variety of stimuli to illustrate body responses. Present Body responses: bowls of water – hot,
their surroundings and to coordinate their behaviour. Information from receptors passes along cells (neurones) as impulses to the central nervous system (the brain or the spinal cord). The central nervous system coordinates the response of effectors which may be muscles contracting or glands secreting hormones. stimulus → receptor → coordinator → effector → response Reflex actions are automatic and rapid; they do not involve the conscious part of the brain. An example of a simple reflex action is the pain withdrawal reflex. This can be explained in terms of a reflex arc. environmental changes and coordinate behaviour. Explain how the nervous system is adapted for its functions. Describe the functions of the main structures in the nervous system. Explain the role of chemicals at synapses. Describe and use different methods to measure reaction time. Required practical Make a plan to investigate a factor on human reaction time. Explain the importance of reflex Explain how detection of stimuli protects the body from danger. Demo: response to different temperatures. Detecting different tastes on the tongue – draw results on diagram of tongue. Investigate sensitivity of different areas of the body. Measure reaction time using different methods, eg Sheep Dash Activity (see resources). Required practical 8: plan and carry out an investigation into the effect of a factor on human reaction time. Biology AT 1, 3 and 4 Plan for required practical. Use knee-jerk and pupil reflexes as a stimulus for discussion. Students discuss their importance and gather other examples leading into and analyse results, eg: response to temperature taste receptors skin sensitivity. Evaluate different methods for measuring reaction time. Give data for conduction velocity (m/s) and axon diameter. Discuss choice for axes and appropriate number at origin. Students plot graph. Show and discuss line of best fit. Required practical 4: investigate the effect of a factor on human reaction time. Biology AT 1, 3 and 4 MS 2c, 4a warm and salt, coffee and lemon solutions to taste hairpins, ruler, blindfolds. Teachit Science resource BBC Bitesize – AQA
Sensory neurones carry impulses from receptors to the spinal cord and brain. Relay neurones carry impulses within the CNS. Motor neurones carry impulses from the CNS to effectors. Where two neurones meet, there is a tiny gap called a synapse. Impulses cross this gap using chemicals. Reaction times vary from person to person. Typical values range from 0.3s to 0.9s. This topic links with 4.7.1.10 Stopping distances actions and give examples. Describe the differences between voluntary and reflex actions. Describe the stages of a reflex action. explanation of why they are faster than a voluntary action. Label a diagram of a reflex arc. Draw a flow diagram or use cards to show the sequence in a reflex action. Use BBC activity (see resources) as a summary of the nervous system. 4.2.1.7 The endocrine system is composed of glands which secrete hormones directly into the bloodstream. Hormones are large molecules. The blood carries the hormone to a target organ where it produces an effect. Describe the endocrine system and define the term hormone. Relate hormone release and hormone action to the control 2 Collective memory or Card sort using hormone name, function and location. Pin the tail on the donkey type activity – give each student a card and get them to stick it on a large body Relate hormone release and hormone action to the control system model. Negative feedback – make an analogy to relaxing in a hot bath. Too hot at first, add Torso and large image of the human body. assess.
to a response that tends to reverse the change. 4.2.2 Plants and photosynthesis 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 apply practical and enquiry skills Self/peer assessment Opportunities and resources Reference to past questions that indicate success 4.2.2.1 Meristem tissue contains the cells in a plant that divide as the plant grows. This type of tissue is found at the growing tips of shoots and roots. The cells differentiate into different types of plant cells depending on where they are in the plant. Describe the function of meristems in plants. 0.5 Discuss how plants grow compared to animals. Show students a time lapse video of seedlings growing. Students list the tissues and organs meristem differentiate into. Look at dividing cells in prepared root tip squash slides. Show images of meristem tissue Prepared slides and microscopes or bioviewers of root tip squashes 4.2.2.2 Plants, like other multicellular organisms, Label the main organs of a plant and 0.5 Discuss which substances a plant needs to transport. Build
to its leaves. Xylem tissue is composed of hollow tubes strengthened by lignin adapted for the transport of water in the transpiration stream from the to the leaves. Water evaporates in the leaves and the water vapour escapes through tiny holes in the surface of leaves called stomata. The stomata can open or close as conditions change because the guard cells can gain or lose water by osmosis. The rate of transpiration varies with: • light intensity, which affects the opening of stomata • air movements, which affect the concentration of water vapour in the air around leaves Define the term ‘transpiration’. Explain why there are more stomata on the lower surface of a leaf. Describe the role of stomata and guard cells to control water loss and gas exchange. Calculate stomatal density. Describe and compare the processes of diffusion, osmosis and active transport. Explain how factors such as light, humidity and moving air affect the rate of transpiration. to take sections and observe the dye in the xylem vessels under the microscope. Observe and draw xylem, and root hair cells. Estimate the size of the cells. Describe how they are adapted for their functions. Recap diffusion and osmosis. Compare them with active transport. Produce a comparison table. Introduce active transport as absorption against the concentration gradient. Discuss when this might be useful. Observe a video or pictures of plants growing in soil and in hydroponic solutions. Suggest why farmers and gardeners turn the soil and hydroponic solutions must be kept aerated. Use the Nuffield activity. Investigate the effect of oxygen availability on the growth of plants. Observe results in later lessons. Nuffield - investigate the effect of changing conditions on the rate of transpiration using a photometer. Students predict then research the effect of humidity on the rate of transpiration. Calculate size of stomata given images and scale bar. coverslips, microscopes. Prepared slides: of phloem and root hair cells, microscopes, bioviewers. Stomata: Leaves from privet and spider plants, kettle, beakers, nail varnish, slides, coverslips and microscopes. Demo: 2 cylindrical balloons, sellotape. Rap:
Extract and interpret information from graphs, charts and tables. 4.2.2.4 The chlorophyll and other pigments in plant leaves can be separated and identified by chromatography. Chromatography can be used to separate mixtures and can give information to help identify substances. The ratio of the distance moved by a compound (centre of spot from origin) to the distance moved by the solvent can be expressed as its Rf value: Different compounds have different Rf values in different solvents, which can be used to help identify the compounds. The Students should be able to: suggest how chromato-graphic methods can be used for distinguishing pure substances from impure substances interpret and determine Rf values from chromato-grams. 1 Describe a method for paper chromatography. Explain what happens to substances during the process of chromatography. Describe to another student what the Rf value is and instructions on how to calculate the Rf value. Required practical 9: investigate how paper chromatography can be used to separate and tell the difference between coloured substances. Students should calculate Rf values. Chemistry AT 1 and 4 clips: YouTube: YouTube:
compounds in a mixture may separate into different spots depending on the solvent but a pure compound will produce a single spot in all solvents. 4.2.2.5 Photosynthesis takes place in the chloroplasts in the cells of the leaves of plants. The chloroplasts contain the chlorophyll, which absorbs sunlight. Photosynthesis is an endothermic reaction that can be represented by word and symbol equations: carbon dioxide + water → glucose + oxygen The glucose produced in photosynthesis may be: used for respiration converted into insoluble starch for storage used to produce fat or oil for storage the word and symbol equation for photosynthesis. Explain why photosynthesis is important for the survival of other organisms. Investigate the need for light, carbon dioxide and chlorophyll to make glucose. Explain why plants should be before photosynthesis experiments and describe how this is done. 2 Collective memory activity for students on leaf structure – self Watch BBC video clip to recap how leaves are adapted for photosynthesis. Discuss what plants need to survive and how plants are useful to 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. Put cards in order to create equation. Set up experiments to show that 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. Carry out the test and interpret the results. Recall test for oxygen. Interpret results of test and relate to Photosynthesis equation
the energy available from light the concentration of carbon dioxide the temperature (HT only) The rate of photosynthesis may be limited by: low temperature shortage of carbon dioxide shortage of light. (HT only) Increasing any one of the factors speeds up photosynthesis until the rate is limited by the factor which is in shortest supply. Interpret data showing how factors affect the rate of photosynthesis. Required practical: carry out an investigation, collect, present and analyse the results. Calculate the rate using numerical information or graphs. 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: ask students to identify various factors, select one to control, plan investigation to investigate its effect and explain the procedure and conclusion. MS 1a, 1c, 2c, 4a, 4c Extract and interpret information from graphs, charts and tables. WS 3.5 (HT only) Understand and use inverse proportion – the inverse square law and intensity in the context of Interpret graphs and calculate the rate of photosynthesis. Required practical 10: investigate the effect of light intensity on the rate of photosynthesis using an aquatic organism such as pondweed. Biology AT 1, 2, 3, 4 and 5
factors affecting photosynthesis. 4.2.2.7 Phloem tissue is composed of of elongated living cells adapted for translocation of sugars from where they are produced by photosynthesis in the leaves to other parts of the plant for immediate use or storage. Cell sap containing sugars and other nutrients is able to move easily from one phloem cell to the next as the end walls have pores. Define the term ‘translocation’. Describe the structure of phloem and relate to its function. Describe how sugar is transported to different parts of the plant. Explain why is transported to other parts of the plant. 0.5 Observe and draw phloem. Recap transport in plants and summarise by labelling a diagram of a plant to show that water enters via the roots and travels in the xylem to the leaves; carbon dioxide enters leaves via stomata; light is absorbed by chlorophyll in leaves; dissolved sugars are transported from the leaves in the phloem to other parts of the plant. Model plant vascular bundles using long cardboard cylinders and boxes. Estimate the scale of the model from given data about xylem and phloem. Prepared slides: of phloem and microscopes or bioviewers. 4.2.2.8 Tobacco mosaic virus is a widespread plant pathogen affecting many species of plants including tomatoes. It gives a distinctive ‘mosaic’ pattern of discolouration on the leaves, which affects the growth of the plant due to lack of photosynthesis. Rose black spot is a fungal disease where purple or Define the term ‘communicable diseases’. Describe the causes, symptoms and control methods of tobacco mosaic disease and rose black spot. 1 Students research the effects of tobacco mosaic and rose black spot fungus. Prepare advice on how horticulturists can control the spread of tobacco mosaic virus and rose black spot. WS 1.4 Explore images of disease on Rothamsted Research website.