The properties of enzymes. The lock and key theory and collision theory can be used to explain enzyme action. Explain why enzymes are specific and are denatured by high temperatures and extremes of pH. Use the lock and key theory and collision theory to explain enzyme action. hydrogen peroxide. Use the observations to lead into the properties of enzymes. Watch a video clip to help to describe the action of catalase. Watch computer simulations to help make notes and explain the properties of enzymes. Make models or cut-outs to demonstrate the of the active site of an enzyme and the shape of the substrate(s). Demo: how the rate of the catalase reaction can be measured using a gas syringe or inverted cylinder of water and timer to prepare for the Required practical next lesson. and boiled liver on hydrogen peroxide. Explore how the rate of a reaction can be measured by measuring the volume of gas given off in a given time. Calculate the rate using data obtained. Discuss how the equipment could be adapted to investigate the effect of a factor on the rate of the reaction. Make predictions and identify variables. or small beakers and goggles. Demo: living tissue, hydrogen peroxide, flask, delivery tube, gas syringe, cylinder and trough, timer. 4.2.2.1 Required practical: Investigate the effect of pH on the rate of reaction of amylase enzyme. Students should use a continuous sampling Carry out a safe, controlled investigation to measure the rate of the catalase under different conditions. Draw a diagram of the apparatus and write a method. Identify variables. Present and analyse the 1.5 Required practical. Required practical: Carry out a safe, controlled investigation to measure the rate of the catalase reaction under different conditions. Draw a diagram of the
technique to determine the time taken to completely digest a starch solution at a range of pH values. Iodine reagent is to be used to test for starch every 30 seconds. Temperature must be controlled by use of a water bath or electric heater. results: calculate rates of reaction using raw data and graphs. Draw conclusions and give explanations for the results. apparatus and write a method. Identify variables. Present and analyse the results: calculate rates of reaction using raw data and graphs. Draw conclusions and give explanations for the results. 4.2.2.1 Human digestive enzymes Enzymes in the digestive system chemically digest food into small, soluble molecules that can be absorbed. of enzymes with substrates, products and sites of production. Bile is made by the liver and stored in the Explain why foods need to be digested into small, soluble molecules. Describe the three types of enzymes involved in digestion, including the names of the substrates, products and where the enzymes are produced. Explain how bile helps in the digestion of fats. 2 Observe a model for digestion using popper beads to illustrate large molecules being broken into smaller ones. Introduce the names of the three groups of digestive enzymes, what they digest and the products formed. Present the information in a table. Use bead model. Investigate the action of amylase on starch a model gut or interpret the results using the computer simulation. Model: Strings of popper beads. Model gut: amylase solution, starch solution, cellulose tubing, beaker, iodine solution, Benedict’s solution, test tubes, spotting tile, waterbath. Demo: large trough of water, greasy frying pan, washing
gall bladder. It helps in the digestion of fats by neutralising acid from the stomach and emulsifying fats. Different enzymes work best at different temperatures and pH values. Required practical: Food Use qualitative reagents to test for a range of carbohydrates, lipids and proteins. To include: Benedict’s test for sugars; iodine test for starch; and Biuret reagent for protein. Interpret graphs to determine the optimum temperature or pH for an enzyme. Carry out other enzyme controlled investigations as appropriate. Calculate the rate of enzyme controlled reactions. Interpret the results from enzyme controlled reactions. Discuss the role of bile and demonstrate the action of washing up liquid on fats. Demonstrate the effect of bile salts on the rate of digestion of milk using a pH indicator. Using a model or large poster of the digestive system identify where each type of enzyme and bile is produced. Add labels to the digestive system diagram to show where the different enzymes and bile are produced. Optional investigations or use computer simulations and interpret and explain the results: Investigate the optimum pH values for pepsin and trypsin. Investigate the effect of temperature on amylase activity. the demos and discuss the outcomes. Explain why pH is measured to indicate the rate of fat digestion. Investigate the optimum pH values for pepsin and trypsin enzymes. Relate the results to their sites of action in the digestive system. Investigate the effect of temperature on amylase activity – measure time taken for starch to disappear. Plot results and find optimum temperature for amylase. Plot and interpret graphs about enzyme activity; determine optimal temperatures and pH values. up liquid, tube of water and olive oil Demo: two tubes full cream milk, sodium carbonate solution, phenolphthalein or UI solution, lipase solution, +/- washing up liquid and timer. pH: Pepsin solution, trypsin solution, buffer solutions at different pH values, UI strips, egg white suspension, test tubes, timers and goggles. Amylase: amylase solution, starch solution, test water baths at different temperatures, thermometers, glass rods, spotting tiles, iodine solution, timers, goggles.
How the lungs are adapted for efficient gas exchange. Describe the function of the pacemaker cells and coronary arteries. Label the main structures in the gas exchange system – trachea, bronchi, alveoli and capillary network around alveoli. Explain how the alveoli are adapted for efficient gas exchange. 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. main structures and discuss the roles. Inflate the lungs with a bicycle pump. The structure of the or model of gas exchange system. Sheep lungs and trachea (PLUCK), bicycle pump 4.2.2.2 Structure and function of arteries, veins and capillaries Explain how the blood vessels are adapted for their function. 1 Use computer simulation or video clip showing the three types of blood vessels and comparing their functions. Extract information to explain the structure of the blood vessels. Observe prepared slides of the different vessels, or use bio-viewers. Compare their size and structure. Measure pulse rate and blood pressure – lying Microscopes, prepared slides, Pulse and blood pressure: timers or pulse rate sensor,
Label diagrams of the three types of blood vessel. Produce a table to compare the structure of the vessels and relate to their function. Demo: how valves in prevent backflow of blood using someone with prominent veins. Students explain the principles of valve action. down, sitting and standing. blood pressure monitor. 4.2.2.4 Coronary disease Fatty material builds up in coronary arteries reducing blood flow to the heart muscle. Stents can be used to keep the coronary arteries open. Statins reduce cholesterol levels, so material is deposited more slowly. Faulty heart valves can be replaced with Describe problems associated with the heart and explain how they can be treated. Evaluate the use of drugs, mechanical devices and transplants to treat heart problems, including religious and ethical issues. 1 video clip about coronary heart disease. Discuss the different types of heart problems that can occur and how they are treated coronary arteries, heart attack, faulty valves, hole in the heart, drugs, transplants, artificial hearts and replacement valves. Produce a report or PowerPoint presentation. Observe illustrations of artificial hearts and replacement valves. Demo: Calculate the rate of water flow through tubing. Evaluate the use of models to represent blocked arteries. Artificial heart and valves if available otherwise show illustrations. Demo: Rigid, transparent tubing – one left open and the other partially blocked with wax, funnel, measured volumes of water, timer.
catching an infectious disease. Viral infections can trigger cancers. Immune reactions can trigger allergies. Physical ill-health can lead to depression and mental illness. Various risk factors are linked to some disease. Type 2 diabetes, lung diseases and cancers. how effective they are and why. Brainstorm the human and financial cost of these diseases on individuals, communities, nations and globally. Role-play a doctor and patient discussing the benefits and difficulties of one lifestyle change, eg smoking, alcohol, diet or exercise. diseases, looking for correlations. Measure height and weight to calculate BMI. Calculate BMI and evaluate the use of this type of measurement. 4.2.2.7 Cancers (malignant tumours) result from uncontrolled cell division. Cancer cells may invade neighbouring tissues, or break off and spread to other parts of the body in the blood, where they form secondary tumours. Describe some causes of cancer, eg viruses, smoking, alcohol, carcinogens and ionising radiation. Describe the difference between benign and malignant tumours. Explain how cancer may spread from one site in the body to form a secondary tumour in another part of the body. 1 Watch animation about cancer on ABPI site (see resources). Research the causes of cancer and cancer treatment. Explore activities and information on cancer research site. Analyse data about cancer from cancer research site.
4.2.3.1 The leaf is the organ of photosynthesis. Examples of tissues in a leaf: epidermis, palisade and spongy mesophyll, phloem, guard cells and stomata. How these tissues are adapted for their function. Explain why 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. Label a diagram of a cross section through a leaf. Describe how the tissues are adapted for their role in photosynthesis. Investigate the arrangement of stomata and suggest reasons for this distribution. Calculate stomatal density using data provided or from direct observations. Demonstrate how guard cells open and close the stomata. Observe the video clip showing stomata. Explain how the guard cells and stomata control water loss and gas exchange. Listen to the rap photosynthesis and leaf structure. reasons why there are more stomata on the lower surface. Draw the arrangement of stomata and guard cells observed. spider plants, kettle, beakers, nail varnish, slides, coverslips and microscopes. Demo: 2 cylindrical balloons, sellotape. Rap: 4.2.3.1 4.2.3.2 Plant transport systems Describe the organs that make up the plant transport system. 1 Demonstrate capillary action using in a long capillary tube and coloured dye. Evaluate the use of a model to show water Demonstrate long piece of capillary tubing supported in
The roots, stem and leaves form a plant transport system. Root hair cells absorb water by osmosis and mineral ions by diffusion and active transport. (See next lesson). Xylem tissue transports water and dissolved ions. The flow of water from the roots to leaves is called the transpiration stream. Xylem tissue is composed of hollow tubes strengthened with lignin. Phloem tissue transports dissolved sugars from the leaves to parts of the plant. The movement of food through Describe the role of xylem, phloem and root hair cells and explain how they are adapted for their functions. Define the terms ‘transpiration’ and ‘translocation’. Demonstrate transport of coloured dye in celery or a stem then allow students to take sections and observe the dye in the xylem vessels under the microscope. Observe and draw xylem, phloem and root hair cells. Estimate the size of the cells. Describe how they are adapted for their functions. Label 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. transport in a plant stem. Prepare sections of celery or plant stem and observe under a microscope. Observe prepared slides or bioviewers of and phloem cells; draw them and estimate their size. clamp, beaker of coloured water. stalks: celery of plant stalk in beaker of coloured water, scalpels, tiles, slides and coverslips, microscopes. Prepared slides: of xylem, phloem and root hair cells, microscopes, bioviewers.
phloem is called translocation. Phloem cells have pores in their end walls for movement of cell sap. 4.1.3.3 4.1.3.3 Active transport Active transport involves the movement of a substance against a concentration gradient and requires energy from respiration. Mineral ions can be absorbed by active transport into plant root hairs from very dilute solutions in the soil. Sugar can be absorbed by active transport from the gut into the blood. Define the term ‘active transport’. Describe where active transport occurs in humans and plants and what is transported. Explain why active transport requires energy. Explain how active transport enables cells to absorb ions from very dilute solutions. Explain the relationship between active transport and oxygen supply and numbers of mitochondria in cells. 0.5 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. Research where active transport occurs in plants and humans and label these on diagrams with notes. 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. Investigate the effect of oxygen availability on the growth of plants. Observe results in lessons. Use of a Oxygen: gas jars with lids, glass tubes, fresh and boiled water to make mineral ion solution(s), black paper.