Spec ref. Summary of the Learning outcomes Suggested Opportunities to develop Opportunities to Self/peer specification content What most students should be able timing Scientific Communication skills develop and apply assessment to do (hours) practical and enquiry opportunities and skills resources Reference to past questions that indicate success 4.1.3.1 Diffusion Define the term 2 Observe demos and suggest Choose investigations Demo materials: ‘diffusion’. explanations: as appropriate: strong Time how long it is before potassium Substances can move Explain how temperature, perfume students can smell a permanganate in into and out of cells concentration gradient and concentrated perfume placed in a corner beaker of water; across membranes by surface area affect the rate of NH4OH of the room. potassium diffusion. diffusion. concentrated Is the rate of diffusion permanganate on HCl Definition of diffusion Give examples of substances that different for different agar gloves and factors affecting diffuse into and out of cells. gases? Use concentrated investigate mask rate. ammonium hydroxide and diffusion of forceps Calculate and compare surface hydrochloric acid in a large different acids cotton wool Oxygen, carbon area: volume ratios. long glass glass tube. and alkalis dioxide and urea tube with Does temperature affect through agar passes through cell Explain how the small intestine strips of damp the rate of diffusion? Fresh investigate rate of membranes by and lungs in mammals, and roots litmus along beetroot placed in iced diffusion of diffusion. and leaves in plants, are adapted length water and warm water. glucose through for exchange of substances. beetroot Record observations and cellulose tubing Single celled beakers suggest explanations. use digital organisms have a Describe and explain how an kettle microscope to bigger surface area to exchange surface is made more ice Watch a video or computer observe diffusion volume ratio than effective. two gas jars of simulation of diffusion on BBC of particles in milk multicellular NO2 or McGraw-Hill website. or yogurt solution. organisms, so transfer two empty gas Model diffusion. sufficient substances jars. Role play diffusion in gases across their surface. Observe slides or and liquids at different Multicellular organisms micrographs of villi, temperatures and require specialised alveoli, root hair cells concentrations. organ systems to Optional demo and leaves. materials:
Spec ref. Summary of the specification content Learning outcomes What most students 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 4.1.3.1 Diffusion Substances can move into and out of cells across membranes by diffusion. Definition of diffusion and factors affecting rate. Oxygen, carbon dioxide and urea passes through cell membranes by diffusion. Single celled organisms have a bigger surface area to volume ratio than multicellular organisms, so transfer sufficient substances across their surface. Multicellular organisms require specialised organ systems to Define the term ‘diffusion’. Explain how temperature, concentration gradient and surface area affect the rate of diffusion. Give examples of substances that diffuse into and out of cells. Calculate and compare surface area: volume ratios. Explain how the small intestine and lungs in mammals, and roots and leaves in plants, are adapted for exchange of substances. Describe and explain how an exchange surface is made more effective. 2 Observe demos and suggest explanations: Time how long it is before students can smell a perfume placed in a corner of the room. Is the rate of diffusion different for different gases? Use concentrated ammonium hydroxide and hydrochloric acid in a large glass tube. Does temperature affect the rate of diffusion? Fresh beetroot placed in iced water and warm water. Record observations and suggest explanations. Watch a video or computer simulation of diffusion on BBC or McGraw-Hill website. Role play diffusion in gases and liquids at different temperatures and concentrations. Choose investigations as appropriate: potassium permanganate in beaker of water; potassium permanganate on agar investigate diffusion of different acids and alkalis through agar investigate rate of diffusion of glucose through cellulose tubing use digital microscope to observe diffusion of particles in milk or yogurt solution. Model diffusion. Observe slides or micrographs of villi, alveoli, root hair cells and leaves. Demo materials: strong perfume concentrated NH4OH concentrated HCl gloves mask forceps cotton wool long glass tube with strips of damp litmus along length beetroot beakers kettle ice two gas jars of NO2 two empty gas jars. Optional demo materials:
AQA-8461-SOW-CELLS.DOCX