a permanent vacuole filled with cell sap. and algal cells also have a cell wall made of cellulose, which strengthens the cell. 4.1.3.3 Some substances move Define the term 1 Observe demos and suggest Choose investigations Demo materials: ‘diffusion’. across cell membranes explanations: as appropriate: strong perfume Explain how temperature, via diffusion. Diffusion is Time how long it is before potassium concentrated concentration gradient and a spreading out and pupils can smell a perfume permanganate in surface area affect the rate mixing process. placed in a corner of the beaker of water, concentrated HCl of diffusion. Particles move from a room. potassium gloves region where they are in Is the rate of diffusion permanganate on mask higher concentration to different for different agar forceps a region where their Use concentrated investigate diffusion cotton wool concentration is lower. ammonium hydroxide and of different acids and long glass tube Factors that affect the hydrochloric acid in a large alkalis through agar with strips of rate of diffusion across a glass tube. investigate rate of damp litmus membrane are: Does temperature affect diffusion of glucose along length the rate of diffusion? Fresh through cellulose beetroot the difference in beetroot placed in iced tubing beakers concentration water and warm water. use digital kettle the temperature microscope to ice the surface area of Record observations and observe diffusion of two gas jars of the membrane. suggest explanations. particles in milk or NO2 yogurt solution.
a permanent vacuole filled with cell sap. and algal cells also have a cell wall made of cellulose, which strengthens the cell. 4.1.3.3 Some substances move across cell membranes via diffusion. Diffusion is a spreading out and mixing process. Particles move from a region where they are in higher concentration to a region where their concentration is lower. Factors that affect the rate of diffusion across a membrane are: the difference in concentration the temperature the surface area of the membrane. Define the term ‘diffusion’. Explain how temperature, concentration gradient and surface area affect the rate of diffusion. 1 Observe demos and suggest explanations: Time how long it is before pupils can smell a perfume placed in a corner of the room. Is the rate of diffusion different for different 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. 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. Demo materials: strong perfume concentrated 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
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