Bio - Diffusion and Active Transport 4.0 / 5 based on 2 ratings ? BiologyTransport Across MembranesASAQA Created by: KTPLCreated on: 20-11-16 14:35 What are the 3 basic mechanisms of transport across membranes? Diffusion, Osmosis, Active transport 1 of 22 Which processes are passive? Diffusion and Osmosis 2 of 22 What are the two types of diffusion? Simple diffusion / Facilitated diffusion 3 of 22 What is the result of diffusion? Dynamic Equilibrium 4 of 22 In diffusion, the movement of molecules goes which way? DOWN a concentration gradient (from high conc. to low conc.) 5 of 22 Which process is active, and what does it require? Active transport, energy in the form ATP 6 of 22 Where does simple diffusion happen? Through the membrane where the phospholipid molecules are 7 of 22 What types of molecule are transported in simple diffusion? Small, non-polar molecules 8 of 22 What 6 things affect rate of diffusion? 1. S.A. 2. Thickness of exchange surface. 3. Conc. gradient. 4. Size of diffusing molecule. 5. Temperature. 6. Water solubility/polarity 9 of 22 How do you calculate rate of diffusion (Fick's Law) Rate of Diffusion = S.A. *Difference in conc. / Thickness of exchange surface 10 of 22 How to increase diffusion rate? maximise S.A., maximise concentration difference, minimise thickness of exchange surface. 11 of 22 What does the graph look like for simple diffusion? Directly proportional 12 of 22 What is used in facilitated diffusion? Channel proteins; Carrier proteins 13 of 22 What particles/molecules are transported in facilitated diffusion? Large, or polar molecules 14 of 22 How are different molecules moved through the channel proteins? Specificity - specific channel/carrier proteins for different molecules 15 of 22 What does the protein do to help the molecule move through? Changes shape 16 of 22 What is needed/involved in active transport, aside from energy? Carrier protein (protein pump) 17 of 22 Which way does active transport go on the concentration gradient? AGAINST the concentration gradient 18 of 22 What does active transport require? Energy in the form of ATP 19 of 22 How to active transport work? Ions bind to carrier protein; causes change in channel shape; releases molecule 20 of 22 Can active transport carrier proteins reverse their pump? Yes - enables them to move different molecules the other way 21 of 22 Uses of active transport: Uptake glucose in small intestine; absorb mineral ions in roots; excrete urea/H+ in kidneys; exchange Na+/K+ in neurons and muscle cells 22 of 22
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