LESSON PLAN Sheet 1



PART 3: cellular level of organizationLEARNING OBJECTIVESParts of a CellBriefly explain the functions of the three main cell parts.The Plasma MembraneDescribe the plasma membrane’s structure.Classify membrane proteins on the basis of function.Explain the importance of membrane fluidity to plasma membrane function.Explain how the plasma membrane’s structure makes it semipermeable.Discuss the factors that contribute to an electrochemical gradient.Transport Across the Plasma MembraneDifferentiate between passive and active membrane transport.Define diffusion and describe several factors that affect pare simple diffusion with facilitated diffusion.Explain the principle of osmosis.Describe what happens to a cell placed in an isotonic, hypotonic, or hypertonic pare primary active transport with secondary active pare endocytosis with exocytosis.CytoplasmDescribe cytosol’s chemical composition and function.Construct a chart that describes cytoplasmic organelles’ structure and function.NucleusDescribe the structure and function of the nucleus.Explain how genes are organized in non-dividing and dividing cells.Protein SynthesisDiscuss how DNA and RNA store genetic information.Define gene expression.Describe the sequence of events in gene transcription.Describe the sequence of events in mRNA translation.Cell DivisionDefine cell division. State the two types of cell division and the purpose of each type.Define somatic cell cycle. List the events that occur during the cycle’s interphase.Describe the stages and events of mitosis.Metabolic ReactionsDefine metabolism.Explain the role of ATP in anabolism and catabolism.Metabolic ReactionsDescribe oxidation-reduction reactions.Describe three mechanisms of ATP generation.Carbohydrate MetabolismDescribe the mechanism of glucose movement into body cells.Describe glucose catabolism.Describe glucose anabolism.Lipid and protein MetabolismDescribe the transport of lipids by lipoproteins.Briefly describe lipid catabolism and metabolism.Briefly describe protein catabolism and anabolism.PART 3: cellular level of organizationLEARNING ACTIVITIESParts of a CellThe cell is divided into 3 main parts: plasma membrane, cytoplasm, and nucleus (Figure 3.1). Use Table 3.2 to complete the following chart:Cell PartGeneral FunctionPlasma MembraneCytoplasmCytosol; Organelles, NucleusDraw a generalized cellPlasma MembraneStructure of the Plasma MembraneThe plasma membrane is composed of:A lipid bilayerMembrane proteinsSee Figure 3.2 for an illustration of plasma membrane structure.Fluid mosaic model - ____________________________________________________________The Lipid BilayerThe lipid bilayer is composed of two back-to-back layers made up of 3 types of lipid.PhospholipidsCholesterolGlycolipidsDraw the Lipid BilayerPhospholipids – make the plasma membrane a bilayer because they are amphipathic.Phosphate heads are hydro__________.Fatty acid tails are hydro__________.Phospholipids make the plasma membrane fluid.They are not chemically bonded to each other – they can move about laterally.Phospholipids prevent large polar molecules from crossing the plasma membrane.Water-soluble molecules __________ cross the plasma membrane.Lipid-soluble molecules __________ cross the plasma membrane.Cholesterol is interspersed among the other lipids in both layers of the membrane.Cholesterol molecules maintain the plasma membrane’s fluidity.They prevent hydrophobic interactions between phospholipid tails, which could cause crystallization of the bilayer and decrease membrane fluidityGlycolipids make the lipid bilayer asymmetric.They are only found on the extracellular side of the bilayer.Arrangement of Membrane ProteinsMembrane proteins are classified based on their location in the plasma membrane:Integral proteins – Transmembrane proteins - Peripheral proteins – Functions of Membrane ProteinsProteins comprise a small portion of the plasma membrane, but give it most of its functions.Functions of membrane proteinsIon channelCarrierReceptorEnzymeLinkerCell identity markerSee Figure 3.3 for an illustration of membrane protein function.Membrane FluidityMembranes are fluid structure.Phospholipids and many membrane proteins easily rotate and move sideways in their own half of the bilayer.Fluidity allows the plasma membrane to:Interact with its other components (e.g. assembly of membrane proteins).Move (e.g. phagocytosis).Seal when torn or punctured.Explain the importance of membrane fluidity to plasma membrane function.Membrane PermeabilityThe plasma membrane’s structure makes it semipermeable.The lipid bilayer allows passage of _________________ substances but not _________ substances.Ion channels and carriers allow passage of ________ substances but not _____________ substances.Gradients Across the Plasma MembraneConcentration gradient – Due to the plasma membrane’s selective permeability.Examples:Na+K+Electrical gradient – Typically, the plasma membrane’s inner surface is more __________ charged and the outer surface is more __________ charged.This charge difference is termed the membrane potential.Electrochemical gradient – the combined influence of the concentration and electrical gradients on ion movement.Example: Na+ movement through a membrane channelTransport Across the Plasma MembraneSubstances move across the plasma membrane via passive or active membrane transport processes:Passive ProcessesActive ProcessesDirection substance movesEnergy requirementsFor definitions of membrane transport processes, see Table 3.1 Transport of Materials Into and Out of Cells.Passive Transport Processes - DiffusionDiffusion – Several factors affect diffusion rate:Steepness of the concentration gradientTemperatureMass of the diffusing substanceSurface areaDiffusion distance3 types of diffusion across the plasma membrane:DefinitionSubstances TransportedSimple diffusionFacilitated diffusionOsmosisWater movement (osmosis) can also be expressed with reference to the solute:Water moves from areas of __________ solute concentration to areas of __________ solute concentration.0.9% Solute Solution0.5% Solute SolutionFor each of the diagrams, draw an arrow to indicate net water movement (if applicable):0.9% Solute Solution1.5% Solute Solution0.9% Solute Solution0.9% Solute SolutionOsmotic Equilibrium – Equilibrium is reached when water’s hydrostatic pressure on the receiving side of the membrane is high enough to counteract osmosis.Osmotic Pressure –Osmotic pressure is directly related to solute concentration:Higher solute concentration = __________ osmotic pressure.Lower solute concentration = __________ osmotic pressure.Osmotic pressure describes a solution’s tendency to draw water into it:Higher osmotic pressure = __________ tendency to draw water in.Lower osmotic pressure = __________ tendency to draw water in.Tonicity – Three types of solutions:IsotonicHypertonicHypotonicHypertonicIsotonicHypotonicSolute concentrationOsmotic pressureNet water movementWhat happens to a red blood cell (0.9% solute) when it is suspended in an isotonic saline solution? _______________.What happens to a red blood cell (0.9% solute) when it is suspended in a hypertonic saline solution? _____________________________________. This is called _____________________.What happens to a red blood cell (0.9% solute) when it is suspended in a hypotonic saline solution? _____________________________________. This is called _____________________.See Figure 3.9 Tonicity and its effects on red blood cells.Active Transport ProcessesActive transport processes move substances across the plasma membrane against their chemical or electrical gradients; ATP is always required.Active membrane transport processes include:Primary active transportSecondary active transportEndocytosisPinocytosisDefinitionSubstances TransportedPrimary active transportSecondary active transportEndocytosisPinocytosisCytoplasmCytoplasm is divided into 2 components:CytosolOrganellesTypes of Organelles (use Table 3.2 to complete the chart):PartStructureFunctionsCytoskeletonCentrosomeCilia and flagellaRibosomeRough endoplasmic reticulumSmooth endoplasmic reticulumGolgi complexLysosomePeroxisomeMitochondrion ................
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