Lilac Potato
Mind Map by , created more than 1 year ago

A mind map showing information about osmosis, gas & solute exchange, diffusion through cell membranes (alveoli & villi) and active transport.

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Lilac Potato
Created by Lilac Potato almost 10 years ago
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GCSE AQA Biology 3 Movement in & out of CellsOsmosisDefinition: the movement of water from an area ofhigh concentration to an area of low concentrationthrough a partially permeable membranePartially permeable membrane has very small holesin it - only tiny molecules like water can pass throughWater molecules pass both waysthrough the membrane during osmosis- molecules move about randomlyMore on one side - net flow ofwater to area of low concentrationStronger sugar solution gets more dilute- water acts like it's trying to even upthe concentration on either sideTissue fluid surrounds cells in body -water with oxygen, glucose etcWill usually have different concentration to fluidinside cell - water will move in or out of the cellIf cell is short of water it will be concentrated - solutionoutside is dilute, water will move in by osmosisIf cell has lots of water, will be more dilute -water will be drawn out of cell by osmosisGas & soluteexchangeSubstances move by diffusion,osmosis & active transportLife processes need gases/otherdissolved substances & waste substancesalso need to move out of cellsHave to move through exchange surfaces which are adaptedby:Being thin - shorterdiffusion distanceHaving a large SA - lots ofsubstance can diffuse at onceHaving lots of blood vessels(animals) - to get stuff in/out of bloodBeing ventilated(animals) - air movesin/outStructure of leaves lets gases diffusein/outCarbon dioxide diffuses into air spaces in leaf, then into cellsUnderneath of leaf is an exchange surface - coveredin stomata which carbon dioxide diffuses in throughOxygen & water vapour diffuse out through stomataSize of stomata controlled by guard cells - close ifplant is losing water faster than getting from rootsFlattened shape of leaf increasesarea of exchange surfaceWalls of cells inside leaf =another exchange surface - airspaces inside leaf increase area ofsurfaceWater vapour evaporates from cellsinside leaf, escapes by diffusion (lotsinside, less outside) = evaporationquickest in hot, dry, windy conditionsDiffusion through cell membranesGas exchange happens in the lungs - lungs transfer oxygento RBC & remove waste carbon dioxide from plasmaLungs contain aveoli wheregas exchange takes placeAdapted to maximise diffusion ofoxygen & carbon dioxide byhaving:Large SAMoist lining - fordissolving gasesThinwallsGood bloodsupplySmall intestine is covered in villi - they increase thesurface area so digested food is absorbed quickly into thebloodAdapted byhaving:Single layer of surfacecellsGood blood supply toassist quick absoptionActive transportDefinition: The process that allows substances to be absorbed against a concentrationgradient (from low to high concentration) which requires energy (from respiration)Root hairs - specialised toabsorb water & mineralsCells on surface of plant rootsgrow into hairs which increase SAThe concentration of minerals is usually higher inthe root hair cell - active transport has to happenUsed in gut - when there's low concentrationof nutrients in gut but high in bloodHas to absorb against concentrationgradientDouble click this nodeto edit the textClick and drag this buttonto create a new node