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Movement of substances
The plasma membrane controls the movement of substances into and out of cells using transport proteins and is selectively permeable, allowing some molecules to pass through more easily than others. Cell membranes use passive diffusion, facilitated diffusion requiring transport proteins, and active transport using energy to regulate the flow of nutrients, waste, and other molecules into and out of cells. The fluid mosaic model describes cell membranes as a phospholipid bilayer with various embedded proteins that can move laterally within the membrane.
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Movement of substances
- 3. Substances needed bythe cellsSubstances needed by the cells WaterWater OxygenOxygen NutrientNutrient – GlucoseGlucose – Amino acidAmino acid – MineralMineral – Fatty acidFatty acid – VitaminVitamin The substances have to move across theThe substances have to move across the membranemembrane
- 4. Substances to beeliminate fromSubstances to be eliminate from the cellsthe cells Carbon dioxideCarbon dioxide UreaUrea ToxinToxin
- 6. Fluid Mosaic ModelFluidMosaic Model 1972 - Singer and Nicolson called the1972 - Singer and Nicolson called the membrane amembrane a “Fluid Mosaic Model”.“Fluid Mosaic Model”. Mosaic:Mosaic: different proteinsdifferent proteins embedded inembedded in thethe phospholipids.phospholipids. Fluid:Fluid: proteins and phospholipids canproteins and phospholipids can move freely in themove freely in the membrane.membrane.
- 10. Components ofa phospholipidComponents of a phospholipid bilayer.bilayer. 1.1. phospholipidsphospholipids 2.2. proteins -proteins - enzymes, receptors,enzymes, receptors, transport.transport. 3.3. glycolipidsglycolipids 4.4. glycoproteinsglycoproteins 5.5. carbohydratescarbohydrates 6.6. cholesterolcholesterol
- 11. Plasma MembranePlasma Membrane Boundary that separates theBoundary that separates the living cellliving cell from it’sfrom it’s non-livingnon-living surroundings.surroundings. Phospholipid bilayerPhospholipid bilayer AmphipathicAmphipathic - having both:- having both: hydrophilic headshydrophilic heads hydrophobic tailshydrophobic tails ~8 nm thick~8 nm thick PhospholipidPhospholipid
- 15. Controls trafficControlstraffic into and out of the cellinto and out of the cell withwith phospholipidsphospholipids andand transporttransport proteinsproteins.. Selectively permeableSelectively permeable >>> semi-permeable>>> semi-permeable Transport proteinTransport protein
- 16. What is SelectivePermeability?What is Selective Permeability? TheThe propertyproperty ofof biological membranesbiological membranes which allows some substances to crosswhich allows some substances to cross more easily than others.more easily than others.
- 17. Transport ProteinsTransport Proteins TransportsTransports moleculesmolecules oror ionsions acrossacross biological membranesbiological membranes Two types:Two types: – Carrier proteinsCarrier proteins – Pore proteinsPore proteins
- 18. Through phospholipids layer: Nonpolar molecules = Oxygen. Carbon dioxide, water , lipid soluble molecules By pore – proteins : water soluble molecules and ions By carrier- proteins and energy : ions. By carrier- proteins : glucose, amino acids.
- 19. Passive transport:Passivetransport: NONO energyenergy is expended.is expended. – Simple diffusion – gases,Simple diffusion – gases, – Osmosis – waterOsmosis – water facilitated diffusion:facilitated diffusion: type oftype of passive transportpassive transport which useswhich uses transporttransport proteins.proteins. –– glucose and amino acidglucose and amino acid Active transport :Active transport : – Using carrier protein and energy – ionsUsing carrier protein and energy – ions
- 20. DiffusionDiffusion The net movementof a substance (molecules) down a concentrationconcentration gradientgradient from an area of highhigh conconcentrationcentration to an area of lowlow concentrationconcentration.
- 26. Facilitated diffusionFacilitated diffusion Allows diffusion of large, membrane insoluble compoundsAllows diffusion of large, membrane insoluble compounds such as sugars and amino acidssuch as sugars and amino acids Does not require energy (passive)Does not require energy (passive) Highly SelectiveHighly Selective Substance binds to membrane- transport proteinSubstance binds to membrane- transport protein Fully reversible - molecules may enter the cell and leaveFully reversible - molecules may enter the cell and leave the cell through the transport protein.the cell through the transport protein. Particles move from areas of high concentration to areas ofParticles move from areas of high concentration to areas of low concentration.low concentration. Movement rate of particles will saturateMovement rate of particles will saturate – Maximum rate limited by number of transportersMaximum rate limited by number of transporters – Once all transporters are operating at 100%, an increase inOnce all transporters are operating at 100%, an increase in concentration will not increase rateconcentration will not increase rate
- 29. Active TransportActive Transport Movement across membrane with anMovement across membrane with an energy cost (usually against concentrationenergy cost (usually against concentration Used to pump specific compounds in orUsed to pump specific compounds in or out of the cellout of the cell Requires energy to overcome theRequires energy to overcome the concentration gradient or to allow a largeconcentration gradient or to allow a large or charged particle to cross membraneor charged particle to cross membrane Requires specific integral membraneRequires specific integral membrane proteinsproteins – Can be saturated like facilitated diffusionCan be saturated like facilitated diffusion proteinsproteins – The energy requirement distinguishes activeThe energy requirement distinguishes active transport from facilitated diffusiontransport from facilitated diffusion
- 32. OsmosisOsmosis The movementofThe movement of waterwater acrossacross selectively permeable membranesselectively permeable membranes.. TheThe waterwater moves from amoves from a lowlow concentration areaconcentration area toto highhigh concentration areaconcentration area
- 37. Cell membranes are completelypermeable to water, therefore, the environment the cell is exposed to can have a dramatic effect on the cell.
- 40. Hypotonic solutionHypotonic solution Less soluteLess solute More waterMore water Compare to cytoplasm of the cellCompare to cytoplasm of the cell
- 41. Hypertonic solutionHypertonic solution More soluteMore solute Less waterLess water Compare to cytoplasm of the cellCompare to cytoplasm of the cell
- 42. Isotonic solutionIsotonic solution Equal concentration compare toEqual concentration compare to cytoplasm of the cellcytoplasm of the cell
- 43. Hypertonic Solution: • Soluteconcentration of solution higher than cell • More dissolved particles outside of cell than inside of cell • Hyper = more (think hyperactive); Tonic = dissolved particles • Water moves out of cell into solution • Cell shrinks
- 44. Hypotonic Solution: • Soluteconcentration of solution lower than cell • Less dissolved particles outside of cell than inside of cell • Hypo = less, under (think hypodermic, hypothermia); Tonic = dissolved particles • Water moves into cell from solution • Cell expands (and may burst)
- 45. Isotonic Solution: Solute concentrationof solution equal to that of cell No net water movement
- 52. Why the useof excess fertilizer caused wilting in plant?
- 53. Explain these preservationprocess