Movement of Substances - Diffusion PDF

Brewing tea SLS Activity 1-1 What is happening? Diffusion or osmosis? Brewing tea SLS Activity 1-1 Think about this: What is the definition of diffusion/osmosis? What are the particles that are moving? In what dir...

Brewing tea SLS Activity 1-1 What is happening? Diffusion or osmosis? Brewing tea SLS Activity 1-1 Think about this: What is the definition of diffusion/osmosis? What are the particles that are moving? In what direction are they moving? Why are they moving in this direction? If you claim that this is diffusion/osmosis, how is this different from osmosis/diffusion? Brewing tea SLS Activity 1-2 Will hot or cold water brew tea faster? Why? MOVEMENT OF SUBSTANCES Recap! Types of transport Passive Active Movement of molecules which Movement of molecules does not require additional which requires additional energy. energy in the form of ATP It relies solely on the kinetic energy of the moving molecules What are the types of passive/active transport you have learnt? Recap! Can you identify the type of transport shown in each picture? Not in Not in Syllabus! Syllabus! What do you need to know? For each type of transport, Definition Effects on plant and animal tissues Importance for plant and animal tissues FYI – The Fluid Mosaic model Why is transport across membranes essential? Diffusion Diffusion is the net movement of particles from a region where they are of higher concentration to a region where they are of lower concentration (down a concentration gradient). What are some factors affecting rate of diffusion? Diffusion SLS Activity 1-3 & 1-4 Proceed to the following simulation: https://phet.colorado.edu/sims/html/diffusion/latest/diffusion _en.html Visualise the effects of the following factors on the rate of simple diffusion by exploring the simulation following the instructions on SLS 1. Temperature 2. Mass of particle What are some other 3. Concentration gradient factors that can affect rate of diffusion? Factors affecting rate of diffusion Factor Effect Temperature Higher temperature → Diffuse faster SA:V ratio Larger SA:V ratio → Diffuse faster Concentration gradient Steeper gradient → Diffuse faster Size/Mass of particles Smaller particles → Diffuse faster Distance Shorter distance → Diffuse faster Diffusion medium Solid → Slowest; Liquid → Faster Gas → Fastest Factors affecting diffusion across membranes 1) Nature of membrane 2) Size and nature of molecule e.g. Fat soluble molecules can diffuse through the bilayer faster than water soluble ones Diffusion - Significance in living systems Gaseous exchange in lungs Nutrient uptake in roots Think-Pair-Share: What are some other examples of diffusion in living systems (plants & animals)? Why is diffusion important?