EQ: EXPLAIN HOW ACTIVE AND PASSIVE TRANSPORT HELP THE CELL MAINTAIN HOMEOSTASIS. SC B-2.5 EXPLAIN...

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Transcript of EQ: EXPLAIN HOW ACTIVE AND PASSIVE TRANSPORT HELP THE CELL MAINTAIN HOMEOSTASIS. SC B-2.5 EXPLAIN...

  • EQ: EXPLAIN HOW ACTIVE AND PASSIVE TRANSPORT HELP THE CELL MAINTAIN HOMEOSTASIS.SC B-2.5EXPLAIN HOW ACTIVE, PASSIVE, AND FACILITATED TRANSPORT SERVE TO MAINTAIN HOMEOSTASIS OF THE CELL

    Cell Transport

  • CELL TRANSPORTCHAPTER 7 SECTION 3DEFINITIONS:Equilibrium: state that exists when the concentration of a substance is the same throughout a spaceConcentration Gradient: difference in the concentration of a substance across a distance

  • Passive Transportdfn: movement of substances across a cell membrane without requiring energy expenditure by the cell

    Types:DiffusionFacilitated DiffusionOsmosis

  • Passive transportParticles are said to move down their concentration gradient

    It is free!

  • DIFFUSIONThe movement of particles from regions of higher density to regions of lower density

    Also called simple diffusion

    Small, nonpolar molecules pass through the cell membrane by simple diffusionEx: oxygen, carbon dioxide

  • SIMPLE DIFFUSION

  • DIFFUSION RATERate of diffusion affected by:TemperatureSurface areaConcentration gradientSize of molecule

  • SIMPLE DIFFUSION ACROSS a MEMBRANE

  • FACILITATED DIFFUSIONSame as simple diffusion (particles move down their concentration gradient) except particles require the use of a transport protein to cross cell membrane

  • FACILITATED DIFFUSIONBecause it requires a transport protein there is an upper limit to the # of molecules that can enter/exit a cell at any given moment(called Tmax)

  • Facilitated DiffusionGlucose enters cells via facilitated diffusion

  • OSMOSISOsmosis : the diffusion of water from a more dilute solution a more concentrated solution through a membrane that is permeable to water but not to the solute

    solute: what is dissolved in solvent solvent: what dissolves the solute

  • OsmosisAllows cells to maintain water balance as their environment changes

    http://www.stolaf.edu/people/giannini/flashanimat/transport/osmosis.swf

  • OsmosisWater Channels (called aquapores) in membrane to allow polar water molecules to enter/exit cellIn humans used by:Respiratory systemReproductive systemUrinary system (water conservation)Digestive systemHomeostasis of body temperature

  • Osmosis in Red Blood CellsHypertonic SolutionsConcentration of solutes higher than that in cytoplasmWater follows its concentration gradient and moves from ______________ to ___________Cells will _________________, called crenationhttp://www.tvdsb.on.ca/WESTMIN/science/sbi3a1/cells/Osmosis.htm

  • Osmosis in Red Blood CellsIf the solution is hypotonic, there is a lower solute concentration outside the cell than inside the cellWater will move _____________The cell will __________, called hemolysis.

  • Osmosis with Red Blood CellsIf the solution the red blood cell is in has the same concentration of water as the cytoplasm in the cell there will be _________ movement of water.This is called an isotonic solution.

  • Osmosis in Plant Cells

  • PASSIVE TRANSPORThttp://www.northland.cc.mn.us/biology/Biology1111/animations/transport1.html

  • ACTIVE TRANSPORTDfn: the movement of substances against their concentration gradient (against the flow)Substances are moving from an area of lower concentration to an area of higher concentrationThis requires the cell to use energy (ATP)

  • ACTIVE TRANSPORTTWO TYPES:PUMPSVESICLESENDOCYTOSISEXOCYTOSIS

  • ACTIVE TRANSPORT PUMPSUse a carrier protein (like facilitated diffusion) but requires expenditure of energy

    Most common pump:Na+/K+/ATP pump

  • Na+/K+/ATP pumpA carrier protein that uses ATP (1) to actively transport sodium ions (3) out of the cell and potassium ions (2) into the cell.

    This pump keeps the [Na+] inside the cell lower so that osmosis will not cause the cell to swell with water.

  • ACTIVE TRANSPORTVESICLESUsed to transport molecules that are too large to fit thru a carrier protein.EndocytosisCell eating (phagocytosis) or cell drinking (pinocytosis)Cell wraps membrane around material forming vesicle which is taken into cellExocytosisFor moving material out of cellVesicle fuses with cell membrane releasing contents outside of cell

  • ENDOCYTOSISEXOCYTOSIS

  • Endocytosis Exocytosis

  • Active Transport Animationhttp://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/ion_pump/ionpump.html

  • Review Timehttp://www.learnerstv.com/animation/animation.php?ani=164&cat=biology