Presentation on theme: "Ch 4 – A Tour of the Cell The cell is the basic unit of structure and function in the body. Prokaryote v. Eukaryote Are smaller than eukaryotic cells Lack."— Presentation transcript:
1 Ch 4 – A Tour of the CellThe cell is the basic unit of structure and function in the body.Prokaryote v. EukaryoteAre smaller than eukaryotic cellsLack internal structures surrounded by membranesLack a nucleusThere are three principal parts:plasma membrane (plasmalemma)cytoplasm and organellesnucleus..
2 ProkaryoticflagellaNucleoid region (DNA)RibosomesPlasmamembraneCell wallCapsulePili
3 CytoskeletonRibosomesCentrioleLysosomeFlagellumNot in mostplant cellsNucleusSmoothendoplasmicreticulum (ER)GolgiapparatusRoughMitochondrionPlasmamembrane
5 The plasma membrane is composed of a phospholipid bilayer with embedded proteins. Hydrophilicregion ofproteinPhospholipidbilayerHydrophobicregion of protein(b) Fluid mosaic model of membrane
6 The functions of plasma membrane include: selectively permeable and surrounds the cellular contents.regulates the passage of materials into and out of the cell.participates in intercellular communications..
7 Transport of materials across the plasma membrane In general:large macromolecules cannot cross the membranecharged molecules cannot cross the membranesmall, non-charged molecules can crosswater can cross..
8 The cytoplasm (cytosol) is the gelatinous material inside the cell membrane but outside the nucleus. The cytoplasm contains organelles which are sub-cellular structures that perform discrete functions. True organelles are bounded by a phospholipid membrane..
9 The nucleus is a double-membrane organelle containing the nucleic acids (DNA) and at least one nucleolus (contains ribosomal RNA).This organelle stores the genetic infor-mation and contains the blueprints for almost all protein syntheses.DNA RNA protein..
11 Organelles of a Typical Cell RibosomeProduction of proteins – located attached to ER or free-floatingEndoplasmicReticulum (ER)*Rough*SmoothPassageway for materialsProduces proteins & processes molecules for secretionProduces lipids & detoxifies drugs & stores Ca++Golgi ApparatusPackages material for export & processes macromoleculesVacuole & vesicleStorage..
12 Contains digestive enzymes. Each contains one specific enzyme. LysosomeContains digestive enzymes. Each contains one specific enzyme.ChloroplastsCarries out photosynthesis:6CO2 + 6H2O C6H12O6 + 6O2MitochondriaAerobic cellular respiration:C6H12O6 + 6O CO2 + 6H2O +ATPCilia, flagella, microvilliSurface projections – increase surface area & produce movement..
13 CELL-CELL INTERACTIONS Plant cells are encased by cell wallsThese provide support for the plant cellsWalls of two adjacentplant cellsVacuolePlasmodesmata(channels between cells)
14 Animal cells lack cell walls They secrete a sticky covering called the extracellular matrixThis layer helps hold cells togetherAnimal cells connect by various types of junctionsTight junctionsAdhering junctionsCommunicating junctions