7Diffusion through a Membrane Cell membraneSolute moves DOWN concentration gradient (HIGH to LOW)
8Diffusion across a membrane Semipermeable membrane OsmosisDiffusion across a membraneDiffusion of water across a membraneMoves from HIGH water potential (low solute) to LOW water potential (high solute)Semipermeable membrane
9Diffusion of H2O Across A Membrane High H2O potential Low solute concentrationLow H2O potential High solute concentration
10Cell in Isotonic Solution 10% NaCL 90% H2OENVIRONMENTCELLNO NET MOVEMENT10% NaCL90% H2OWhat is the direction of water movement?equilibriumThe cell is at _______________.
11Cell in Hypotonic Solution 10% NaCL 90% H2OCELL20% NaCL80% H2OWhat is the direction of water movement?
12Cell in Hypertonic Solution 15% NaCL 85% H2OENVIRONMENTCELL5% NaCL95% H2OWhat is the direction of water movement?
19Passive Transport Simple Diffusion Doesn’t require energy Moves high to low concentrationExample: Oxygen or water diffusing into a cell and carbon dioxide diffusing out.
20Facilitated diffusion Passive TransportFacilitated diffusionDoesn’t require energyUses transport proteins to move high to low concentrationExamples: Glucose or amino acids moving from blood into a cell.
22Active Transport Requires energy or ATP Moves materials from LOW to HIGH concentrationAGAINST concentration gradient
23Active transportExamples: Pumping Na+ (sodium ions) out and K+ (potassium ions) in against strong concentration gradients.Called Na+-K+ Pump
24Sodium-Potassium Pump 3 Na+ pumped in for every 2 K+ pumped out; creates a membrane potential
25Exocytosis- moving things out. Moving the “Big Stuff”Exocytosis- moving things out.Molecules are moved out of the cell by vesicles that fuse with the plasma membrane.This is how many hormones are secreted and how nerve cells communicate with one another.
26ExocytosisExocytic vesicle immediately after fusion with plasma membrane.
27Moving the “Big Stuff”Large molecules move materials into the cell by one of three forms of endocytosis.
28Pinocytosis Most common form of endocytosis. Takes in dissolved molecules as a vesicle.
29Pinocytosis Cell forms an invagination Materials dissolve in water to be brought into cellCalled “Cell Drinking”
30Example of Pinocytosis mature transport vesiclepinocytic vesicles formingTransport across a capillary cell (blue).
31Receptor-Mediated Endocytosis Some integral proteins have receptors on their surface to recognize & take in hormones, cholesterol, etc.
35Phagocytosis - Capture of a Yeast Cell (yellow) by Membrane Extensions of an Immune System Cell (blue)
36Exocytosis The opposite of endocytosis is exocytosis Exocytosis The opposite of endocytosis is exocytosis. Large molecules that are manufactured in the cell are released through the cell membrane.Inside CellCell environment
40FROM A LOT to NOT Molecules move _______“where there’s _______” Animatioin from:Molecules move_______“where there’s _______”____“where there’s _______”FROMA LOTtoNOT
41DIFFUSION across a space Happens anytime there is a __________ in concentration in one place compared to another= ________________________DIFFERENCEConcentration gradient
42DIFFUSION across a SPACE Molecules move automatically _______ the concentration gradient _______ an area of _______ concentration ____ an area of ________ concentrationEXAMPLESDOWNfromHighertoLowerBlue dye in beaker demo,Someone making popcorn/grilling outStrong perfume,Bad smell in room
43DIFFUSION across a space Diffusion continues until the concentration is ________________ in space= ________________________equal everywhereEquilibrium
44Molecules need to move across membranes in cells Image modiified from:
45Diffusion can happen ________ a _____________ in a cell, too acrossmembrane…as long as membrane will let the molecule _________________pass through
46SELECTIVELY PERMEABLE (Semi-permeable) Video from:SELECTIVELY PERMEABLE (Semi-permeable)See a movie
47CELL EXAMPLE:DIFFUSION automatically moves oxygen from HIGHER concentration (in lungs) to a LOWER concentration (in blood)CO2 automatically moves from where there is aHIGHER concentration(in blood) to where thereis a lower concentration(in lungs)
48BUT…. What if a cell needs to move _____ or ______ molecules? LARGEPOLAR
49What if cell needs to move a molecule _________ the CONCENTRATION GRADIENT? _______________ AGAINST(LOWER HIGHER)Cell example:Want to put MORE glucoseinto mitochondria when there isalready glucose in thereImage from:
50What if cell needs to move molecules really _______ What if cell needs to move molecules really _______? (can’t wait for it to diffuse)FASTCell example:Movement of Na + & K+ ionsrequired to sendnerve signals
51We need a ____ to ____ molecules across cell membranes that _______ across by ___________ WAYHELPcan’t gothemselves
53Kinds of ________ Transport PASSIVE_____________________________________________________________________DiffusionOsmosisFacilitated Diffusion
54DIFFUSION across a membrane DIFFERENCEHappens anytime there is a __________ in _____________ on one side of the membrane compared to the otherconcentrationMolecules that move bydiffusion across membranesin cells:______________OXYGENCARBON DIOXIDESee diffusion animation
55OSMOSIS OSMOSIS DIFFUSION Semi-permeable lower = SPECIAL KIND OF DIFFUSIONIMAGE by RIEDELLOSMOSIS____________See osmosisanimationDIFFUSION__________Movement of molecules across a _________________ membrane from ______ concentration to _____Semi-permeablelowerHigher
57Facilitated Diffusion _______ proteins help diffusion go faster Carrier
58FACILITATED DIFFUSION PASSIVENo energy required = __________________Moves _________ concentration gradientfrom _____________________________________________ grab molecule, change shape, and flip to other side (Like a revolving door)Molecules that move this way in cells:_______________________DOWNHIGHER to LOWERMembrane proteinsGLUCOSE
63Sodium (Na+)- Potassium (K+) Pump Animation from:See a movie about Na+ - K+ pump
64Sodium-Potassium pump ACTIVE___________ transport(requires energy from ______)Special just for Na+ and K + ionsUses integral ___________________ to move moleculesExamples in nerve cells: Na+ is pumped out of cells at same time K + is taken into cellsATPCarrier Proteins
66ENDOCYTOSIS Takes substances into cell ACTIVE_____________transport(requires __________ from ______)Uses small membrane sacs called ______________ to carry substancesenergy ATPVESICLES
672 KINDS of ENDOCYTOSIS Takes substances into cell If taking in:fluid or small molecules =_________________large particles or whole cells =______________Examples in cells:one celled organisms eat this waywhite blood cells get rid of bacteria this wayPINOCYTOSISPHAGOCYTOSIS
70PHAGOCYTOSIS Called “Cell Eating” ___________ destroying _______ germs White blood cellgerms___________ destroying _______
71EXOCYTOSIS Substances released outside of cell ACTIVE__________ transport (requires __________)Substances move in____________Examples in cells:_________ release packaged proteins this wayenergyVESICLESGOLGI
73GOLGI BODIES USE EXOCYTOSIS Video:GOLGI BODIES USE EXOCYTOSISAnimation from:See a Golgi movie
74Endocytosis & Exocytosis Videos from:Endocytosis & ExocytosisWatch a video clip about endo/exocytosisChoose Screen/Switch programs to view
75INSULIN being released by pancreas cells using exocytosis
76What if there is a difference in concentration but solute molecules can’t move across a membrane? WATER will moveuntil concentrationreaches equilibrium
77VOCAB_____________ = substance that is dissolved in a solvent to make a solution_____________ = substance in which a solute is dissolvedSOLUTESOLVENTEX:Koolaid powder = soluteWater = solventKoolaid drink = solution
78Images by Riedell__________________ = mass of a solute in a given volume of solutionCONCENTRATIONMOREThe _______ molecules there are in a given volume the ____________the concentrationGREATER
81OSMOSIS shrinks GREATER THAN Animation from:OSMOSISSee an animationOSMOSIS 4HYPERTONIC: Concentration outside cell is ____________________ inside cellMore water leaves cell than enters so cell ____________GREATER THANshrinks
82Cell in Hypertonic Solution 15% NaCL 85% H2OENVIRONMENTCELL5% NaCL95% H2OWhat is the direction of water movement?
83OSMOSIS Swell and possibly burst LESS THAN Animation from:OSMOSISSee an animation Osmosis3HYPOTONIC: Concentration outside cell is ________________ inside the cell More water enters than leaves cell so cell will ___________________LESS THANSwell and possibly burst
84Cell in Hypotonic Solution 10% NaCL 90% H2OCELL20% NaCL80% H2OWhat is the direction of water movement?
85OSMOSIS ISOTONIC: Concentration outside cell __________ EQUALS concentration inside cellWater entering = water leaving so cell _____________________EQUALSSTAYS THE SAME SIZE
86Cell in Isotonic Solution 10% NaCL 90% H2OENVIRONMENTCELLNO NET MOVEMENT10% NaCL90% H2OWhat is the direction of water movement?equilibriumThe cell is at _______________.
87NO NET MOVEMENT OF H2O (equal amounts entering & leaving) Isotonic SolutionHypotonic SolutionHypertonic SolutionNO NET MOVEMENT OF H2O (equal amounts entering & leaving)Cell Swells & may burstCell shrivels up