2 Passive Transport Cellular Transport Fact: Particles of matter are always in motion no matter what state this random motion helps explain how materials enter and exit the cellThere are 2 ways that materials enter and exit thecell wallPassive Transport- (Without using cell energy)Diffusion, Facilitated Diffusion, or Osmosis2. Active Transport- (Requiring cell energy)
3 This is gonna be hard work!! Active Transport1. Protein Pumps2. Endocytosis3. ExocytosisPassive Transport1. Diffusion2. Facilitated Diffusion3. OsmosishighlowThis is gonna be hard work!!highlowWheee!!!
4 Diffusion (Passive Transport) What is It?Moving molecules have Kinetic EnergyParticles collide and reboundParticles do not lose energyDiffusion- The overall movement of particles from high concentration to low concentration (by random particle movement)How does it work?Most substances in and around the cell are in H20Solutes (Molecules, ions, etc) are usually distributed evenly in the water by the random movement of moleculesWhen the distribution of all of the solutes in the solution is even, the particles can collide but there is no change in concentration
5 Passive Transport Results? If the concentrations inside and outside the cell are not in Dynamic Equilibrium then the molecules will move according to the concentration gradientFlow is always from High to lowHigh Concentration Low Concentration = With the gradientLow Concentration High Concentration = Against the gradient!! (No longer a concentration gradient, no dynamic equilibrium) !!The selective permeability of the cell membrane is not great for allowing ions or polar molecules to pass by diffusion because they are not attracted to non-polar fatty acids. Only a few molecules can pass by diffusion. They include… H2O, O2, N2, CO2
6 Osmosis (Passive Transport) What is it?Osmosis- Diffusion of H2O through a selectively permeable membrane from high to low concentration
7 NOT AT DYNAMIC EQUILIBRIUM OsmosisBeforeHigh conc of H2O on left of Membrane/low conc of soluteLow conc of H2O on right of Membrane/High conc of soluteAfterH2O molecules move from high conc , acrossThe membrane, to low conc until DYNAMICEQUILIBRIUM is reached.(conc solute/water on left = conc solute/ water on right)NOT AT DYNAMIC EQUILIBRIUM
8 Osmosis Isotonic: Concentrated molecules on the inside = Concentrated molecules on the outsideRandom motion allows water in and out, but at the same rateTherefore Noconcentration gradient
9 Osmosis 2. Hypotonic: Concentration Solutes on the Outside < Concentration Solutes insideHigh water on outside, low water insideWater goes into cell, and cell swellsIncrease in cell pressure called TURGOR PRESSURE
10 Osmosis 3. Hypertonic- Concentration Solute Outside > Concentration Solute InsideHigh Water inside, low water outsideWater goes out of cell and decreases cell pressureCell ShrivelsPlasmolysis- Loss of cell pressure
11 BellringerThe two main parts of the cell membrane’s phospholipid bilayer are…?________________ and b. ______________
12 BellringerFrom the Sandwich Baggie Demo, we learned iodine molecules were able to pass through the membrane because they were…?Small enoughAttracted to the starchVery largeFaster to diffuse than starchmolecules
13 BellringerThe Cell Membrane Test is coming soon. Mrs. Weber set up a study group to facilitate our studying. What does the word facilitate mean?
14 BellringerWater and other molecules don’t always share e-’s equally. This give the molecules a partially positive and partially negative charge. We say these molecules are POLAR.Does the cell membrane easilyallow polar molecules?Y or NWhich part of the cell membrane is hydrophobicand dislikes polar molecules? _________________
15 Facilitated Diffusion (Passive Transport) !! Okay…so molecules pass through the cell membrane based on…Size-Small molecules pass easily,-Large molecules do not or cannotPolarity (if the molecule has charged ends it will not be able to pass the hydrophobic lipids)Polar
16 Facilitated Diffusion IonsFacilitated DiffusionSugarsQ: How do LARGE or POLAR molecules enter the cell?A: Through PROTEINS!Common for Sugars, Amino Acids, or charged molecules like ions or polar molecules.Amino Acids
17 Facilitated Diffusion (Passive Transport) Proteins HELP or FACILITATE the passage of larger or polar moleculesKinds of ProteinsChannel Proteins-have a tube down the middle of the protein thru which molecules can diffuseCarrier Proteins-change their shape to fit specific molecules