Lab Safety – Biology 111 Lab 2 – Properties of Water/ OsmosisSlide 2Reminders:TimelineObjectivesWater is a Polar MoleculeTensionWater – The Universal SolventThermal Properties of WaterDensityOther Properties of WaterWhat is pH?Calculations of pHpH IndicatorsPlasma MembraneWhere Are the Plasma Membranes?Plasma MembranesTransport Across the Plasma MembraneTransport Across the Plasma MembraneDiffusionDiffusionOsmosisOsmotic & Turgor PressurePipettes!Cell phones:Timeline and LogisticsLogisticsReminders!Clean UpSummary of DataHomework (10 points)Next ClassLab Safety – Biology 111Lab 2 – Properties of Water/ Osmosis•Gloves, goggles, and closed-toed shoes are required!•Bags/purses/backpacks must be hung on the bench hook.•DO NOT open the demonstration petri dishes containing potassium permanganate! I will be the ONLY person to handle these dishes.•Dispose of Lugol’s solution in the BASE waste container.•DO NOT fill waste containers past the indicated lines. Keep containers closed when not in use.•No food or drink in lab.Lab 2 – Properties of Water/ OsmosisWhitney ([email protected])Help Desk Hours: M 8-9am, W 9-10am or by appointmentReminders:•Lab Safety Forms: –Paper one/ and Howdy one!•Goggles:–If you do not have them:•Bring me your ID – 1 Point has been deducted from your TA Points•Closed Toed Shoes:–If you do not have them:•Bring me your ID – 1 Point has been deducted from your TA PointsTimeline•Quiz 1 (15 mins)•Lab 2 Intro (20 mins)•Lab Logistics/Safety (5 mins)•”Diffusion Across a Plasma Membrane” and “Part 2: Understanding pH” (25-35 mins)•“Water is a solvent” (5 mins)•“Properties of Water” (10 mins)•“Oil and Vinegar” Exp (pg 24) (5 mins)•“Plasmolysis/live Parameciu m” (20 minutes)•Analyze Data/Clean Up (20 mins)•Summary (20 mins)•Potassium Permanganate Demo: Will be announced by TA during lab take measurements every 5 minsObjectives•Examine and describe the unique properties of water•Use three different methods to test the pH of common household products•Draw the structure of the plasma membrane and describe four ways substances enter and leave cells•Differentiate between diffusion and osmosis•Differentiate between passive and active transport•Conduct an experiment to test the factors that affect diffusion across a selectively permeable membrane•Conduct an experiment to determine water potential in plant cellsWater is a Polar Molecule•What is a Polar Molecule?•Hydrogen bonds form between positively charged H+ atoms and negatively charged atoms.•Covalent bonds share electrons within a molecule. This bond is very strong.TensionCohesion•Capillary Action – The way plants pull water from the soil–Water molecules bind to the cellulose of the plant cell wallAdhesion•Surface Tension – A measurement of how difficult it is to stretch or break a liquid’s surface•Transpiration – The way plants move water from the roots to the rest of the plantWater – The Universal Solvent•Water is able to dissolve more and different materials than any other solvent•Solute – substance that is dissolved•Solvent – substance that does the dissolving•Solution – a mixture made up of a solute dissolved in a solvent•Ionic Bonds – bonds formed from the attraction between (+) and (-) charges–Cation – atom that loses one or more electrons–Anion – atom that gains one or more electronsThermal Properties of Water•Water has a high thermal capacity–i.e. water can absorb and retain a lot of heat–What areas benefit from the thermal capacity of water?•It takes a lot of energy to change the temperature of a body of water 1°•Water retains heat once it is warmedDensity•Water is less dense as a solid:–Ice molecules are more organized and form lattices–Ice floats because of the empty space in the lattice–Ice has a peak density at 4°COther Properties of Water•Viscosity–Water has a low viscosity which allows it to flow easily–Which is more viscous: Water or Honey?•Compatibility with Life–Everything we know of on Earth requires water to survive•pH–Water molecules break apart into H+ and OH- ions–The –log of the concentration of H+ equals the pH–The pH of pure water is 7What is pH?•The pH Scale measures acidity and basicity of a given solution–More H+ ions = more acidic–More OH- ions = more basic•The pH Scale is an inverse logarithmic scale from 0 (acidic) to 14 (basic). 7 is neutral on this scale.–-log 10-7 = -(-7)log10 = 7•pH + pOH = 14–This can be a useful calculation to determine pH and pOHCalculations of pH•[H+] x [OH-] = 1 x 10-14–This can be used to calculate the concentration of a type of ions in a solution•pH + pOH = 14–This can be used to calculate the pH or pOHpH Indicators •Acid-Base Indicators -Weak acids or bases-Gradually changes color over a range of pH values (color change interval)•Anthocyanins-Natural compounds that occur in plants (ex. Red cabbage)-Change color in different pH solutions:-Red = acidic solutions-Purple = neutral solutions-Green/Yellow = basic solutions•pH Test Paper-Paper embedded with pH indicators-Good for clear and colored solutions•Electronic pH Meters-Very precise and accuratePlasma Membrane•Plasma Membrane: All cells have a plasma membrane–Animal cells – outer surface of cell–Plant/Fungi/Bacteria – plasma membrane lies just beneath the cell wall–Comprised of phospholipid bilayer (in eukaryotes and bacteria)•Function:–Support–Protection–Regulation of molecules entering/leaving cellWhere Are the Plasma Membranes?Plasma Membranes•Diffusion•Osmosis•Facilitated diffusion•Active transportTransport Across the Plasma Membrane•Diffusion (passive transport): solute molecules move from areas of high concentration to areas of low concentration (Across a plasma membrane, this is limited to hydrophobic molecules or small, uncharged polar molecules ex. water)•Osmosis (passive transport): the diffusion of water molecules•Facilitated Diffusion (passive transport): requires the assistance of proteins to carry solute molecules down their concentration gradient across the plasma membrane (hydrophilic molecules)•Active Transport: requires energy input (ATP) and proteins to move solute molecules against their concentration gradientsTransport Across the Plasma MembraneDiffusionThese terms are relative: i.e they must be used in a comparisonstatement