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Set your clicker frequency to CCWhat is due by 11:59PM Sunday night?A. Quiz 1 onlyB. 3 Things I learned in BIO 151 onlyC. Homework 1 onlyD. Homework 1 and 3 things I learnedE. Quiz 1, Homework 1, and 3 things I learnedFirst clicker question!!!!Announcements• Login to the iClicker app and register your iClicker.• Complete the BioPrep Chemistry & Biomolecules modules.• HW is open and due by Sunday night (11:59PM)• 3 things I learned this week - Opens today at 10AM and closes Sunday at 11:59PM.• First day of class survey & syllabus quiz (on Moodle). Closes Monday, September 12, 11:59PM.• Pretest (on Moodle) – 2 pts extra credit. By Wednesday 9/14.• Office hours (and discussion sections) begin next week.Our BIO 151 Teamhttps://i.ytimg.com/vi/uXdzuz5Q-hs/maxresdefault.jpgUndergraduate TAsLily GrigelyOlivia MozokiWyatt TranWilliam RyanYashri MehtaEmily Kim Kate FauconMaitri NaikPeter CoufosShri SriprasadShriya ShuklaShruthi SenthilkumarGraduate TAsJuliaJamieGabbySexual assault is a big problem on college campusesI’ve included links to these resources on Moodle.I am glad you are here today.Plasma Membrane Structure & FluidityOutline for today:• Brief overview of plasma membrane structure & the fluid mosaic model.• Membrane fluidity – temperature, chain length, chain saturation.Which of the following is a phospholipid?A.B. C. D.Set your clicker frequency to CCWhich of the following is the best definition of amphipathic?A. Able to dissolve in water.B. Able to dissolve only in polar solutions.C. A molecule that can only mix with other non-polar molecules.D. Contains both hydrophilic and hydrophobic parts.E. Belonging to the plasma membrane.All cells have a plasma membrane.A.TrueB.FalseEukaryotic cellsProkaryotic cellshttps://www.toppr.com/ask/content/concept/cell-number-and-shape-200249/Plasma membrane structurehttps://www.khanacademy.org/science/biology/membranes-and-transport/the-plasma-membrane/a/structure-of-the-plasma-membraneSemipermeable phospholipid bilayerbiology.stackexchange.com/questions/34679/why-dont-phospholipid-bilayers-dissolve cancurecancer.org/wp-content/uploads/2015/09/liposome.pngForms spontaneouslysome molecules can get through while others cannot.Fluid mosaic modelPlasma membrane fluidityTemperatureCholesterolTypes of fatty acidswww.biology-pages.info/C/Cholesterol.gifLong vs. shortSaturated vs unsaturatedTemperatureCholesterolTypes of fatty acidswww.biology-pages.info/C/Cholesterol.gifLong vs. shortSaturated vs unsaturatedWhich of these factors (external temperature, cholesterol content, and/or types of fatty acids), can be changed by cells?A. Cholesterol content only.B. Types of fatty acids only.C. Cholesterol content and types of fatty acids.D. External temperature and cholesterol content.E. External temperature, cholesterol content, and types of fatty acidsPlasma membrane fluidityBioNinjawww.quora.comMore fluid Less fluidhttps://flavorpourfection.comWikimedia commons(more molecular interactions)(fewer molecular interactions)True or False. As temperature increases, membrane fluidity increases.A. TrueB. FalseCells regulate membrane fluidity to maintain homeostasis by adjusting membrane lipid composition.CholesterolTypes of fatty acidswww.biology-pages.info/C/Cholesterol.gifMore fluid membrane = more permeable.Less fluid membrane = more ridged, stronger, less permeable.Homeostasis: any self-regulating process by which an organism tends to maintain stability. So the organism can maintain a stable internal environment. Usually involves negative feedback loops.Starbucks.comBlood sugar rises.Homeostasis of blood sugar levels.Pancreases secretes insulin into the blood.Insulin signals for cells to uptake (take in) glucose. Blood sugar falls.Low blood sugar tells pancreas to stop secreting insulin.Internal body temperature homeostasis.https://opentextbc.ca/biology2eopenstax/chapter/homeostasis/Olive oil (unsaturated)Wikimedia commonsSaturated = no carbon-carbon double bonds.Unsaturated = at least one carbon-carbon double bond.Butter (saturated)https://flavorpourfection.comSteric acidOleic acidLinoleic acidWhich of the following statements is/are true?I. Steric acid is unsaturated.II. Linoleic acid is the only unsaturated fatty acid.III. Oleic and linoleic acid are both unsaturated fatty acids.IV. Oleic and linoleic acid are both saturated fatty acids.A.I onlyB. II onlyC.III onlyD.IV onlyE.I and IVSynechocystis is a genus of unicellular, freshwater cyanobacteria. Researchers mutated Synechocystis genes and these mutations caused a decrease in the percentage of unsaturated fatty acids in the plasma membrane compared to the wild type (Los & Murata, 2004).(mutant)AlchetronMembrane fluidityWhat happens to membrane fluidity temperature increases?A. Membrane fluidity increases.B. Membrane fluidity decreases.C. Membrane fluidity increases for the wild-type, but decreases for the mutant.D. Membrane fluidity decreases for the wild-type, but increases for the mutant.E. Membrane fluidity doesn’t change.Synechocystis is a genus of unicellular, freshwater cyanobacteria. Researchers mutated Synechocystis genes and these mutations caused a decrease in the percentage of unsaturated fatty acids in the plasma membrane compared to the wild type (Los & Murata, 2004).(mutant)AlchetronMembrane fluidityWhat happens to membrane fluidity as the percentage of unsaturated fatty acids decreases?A. Membrane fluidity increases.B. Membrane fluidity decreases.C. Membrane fluidity increases up to a point and then levels out.D. Membrane fluidity increases as temperature increases.Why does having more unsaturated hydrocarbons in a plasma membrane increase membrane fluidity?Think-Pair-Slack1. Think of your answer to this question.2. Discuss it with your peers – one person per group, begin typing a group answer in Slack.3. Post your answer in Slack.PC, PG, PE, PA, PS are different phospholipids. Transition temperature is a way to measure membrane fluidity. A higher transition temperature means a less fluid membrane. What happens to membrane fluidity as the hydrocarbon chain length increases?A. Membrane fluidity increases as chain length increases.B. Membrane fluidity decreases as chain length increases.C. There is no relationship between membrane fluidity and chain length.D. The relationship between membrane fluidity and chain length is positive for some phospholipids, but negative for others. Less fluidMore fluidHydrocarbon chain lengthChanges to


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UMass Amherst BIOLOGY 151 - Notes

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