Overview: The Fundamental Units of LifeSlide 2Slide 3Slide 4Eukaryotic cells have internal membranes that compartmentalize their functionsSlide 6Slide 7A Panoramic View of the Eukaryotic CellSlide 9Slide 10The Nucleus: Information CentralSlide 12Ribosomes: Protein FactoriesSlide 14The endomembrane system regulates protein traffic and performs metabolic functions in the cell1- Nuclear envelope- encloses nucleus2- The Endoplasmic Reticulum: Biosynthetic FactoryFunctions of Smooth and Rough ERSlide 193- Golgi Apparatus: Shipping and Receiving CenterSlide 214- Lysosomes: Digestive CompartmentsSlide 23Slide 245- Vacuoles: Diverse Maintenance CompartmentsSlide 265- Plasma membrane - selective barrierThe Endomembrane SystemMitochondria and chloroplasts change energy from one form to anotherMitochondria: Chemical Energy ConversionSlide 31Chloroplasts: Capture of Light EnergySlide 33The cytoskeleton is a network of fibers that organizes structures and activities in the cellSlide 35Cilia and FlagellaOverview: The Fundamental Units of Life•All organisms are made of cells•The cell is the simplest collection of matter that can live•Cell structure is correlated to cellular function•All cells are related by their descent from earlier cells•Scientists use microscopes to visualize cells too small to see with the naked eye•In a light microscope (LM), visible light passes through a specimen and then through glass lenses, which magnify the imageFig. 6-210 m1 m0.1 m1 cm1 mm100 µm10 µm1 µm100 nm10 nm1 nm0.1 nmAtomsSmall moleculesLipidsProteinsRibosomesVirusesSmallest bacteriaMitochondrionNucleusMost bacteriaMost plant and animal cellsFrog eggChicken eggLength of some nerve and muscle cellsHuman heightUnaided eyeLight microscopeElectron microscope•Most subcellular structures, including organelles (membrane-enclosed compartments), are too small to be resolved by an LM •Two basic types of electron microscopes (EMs) are used to study subcellular structures •Scanning electron microscopes (SEMs) focus a beam of electrons onto the surface of a specimen, providing images that look 3-D•Transmission electron microscopes (TEMs) focus a beam of electrons through a specimen •TEMs are used mainly to study the internal structure of cellsFig. 6-4(a) Scanning electron microscopy (SEM)TECHNIQUE RESULTS(b) Transmission electron microscopy (TEM)CiliaLongitudinalsection ofciliumCross sectionof cilium1 µm1 µmEukaryotic cells have internal membranes that compartmentalize their functions•The basic structural and functional unit of every organism is one of two types of cells: prokaryotic or eukaryotic•Only organisms of the domains Bacteria and Archaea consist of prokaryotic cells•Protists, fungi, animals, and plants all consist of eukaryotic cells•Basic features of all cells: 1. Plasma membrane 2. Chromosomes (carry genes)3. Semifluid substance called cytosol4. Ribosomes (make proteins)•Prokaryotic cells are characterized by having1. No nucleus2. DNA in an unbound region called the nucleoid3. No membrane-bound organelles4. Cytoplasm bound by the plasma membrane•Eukaryotic cells are characterized by having1. DNA in a nucleus that is bounded by a membranous nuclear envelope2. Membrane-bound organelles3. Cytoplasm in the region between the plasma membrane and nucleusFig. 6-6FimbriaeNucleoidRibosomesPlasma membraneCell wallCapsuleFlagellaBacterialchromosome(a) A typical rod-shaped bacterium(b) A thin section through the bacterium Bacillus coagulans (TEM)0.5 µmA Panoramic View of the Eukaryotic Cell•Eukaryotic cells are generally much larger than prokaryotic cells•A eukaryotic cell has internal membranes that partition the cell into organelles•Plant and animal cells have most of the same organelles•The nucleus contains most of the DNA in a eukaryotic cellFig. 6-9aENDOPLASMIC RETICULUM (ER)Smooth ERRough ERFlagellumCentrosomeCYTOSKELETON:MicrofilamentsIntermediatefilamentsMicrotubulesMicrovilliPeroxisomeMitochondrionLysosomeGolgiapparatusRibosomesPlasma membraneNuclearenvelopeNucleolusChromatinNUCLEUSFig. 6-9bNUCLEUSNuclear envelopeNucleolusChromatinRough endoplasmic reticulumSmooth endoplasmic reticulumRibosomesCentral vacuoleMicrofilamentsIntermediate filamentsMicrotubulesCYTO-SKELETONChloroplastPlasmodesmataWall of adjacent cellCell wallPlasma membranePeroxisomeMitochondrionGolgiapparatusThe Nucleus: Information Central•The nucleus contains most of the cell’s genes and is usually the most conspicuous organelle•The nuclear envelope encloses the nucleus, separating it from the cytoplasm•The nuclear membrane is a double membrane; each membrane consists of a lipid bilayer•In the nucleus, DNA and proteins form genetic material called chromatin •Chromatin condenses to form discrete chromosomes•The nucleolus is located within the nucleus and is the site of ribosomal RNA (rRNA) synthesisFig. 6-10NucleolusNucleusRough ERNuclear lamina (TEM)Close-up of nuclear envelope1 µm1 µm0.25 µmRibosomePore complexNuclear poreOuter membraneInner membraneNuclear envelope:ChromatinSurface ofnuclear envelopePore complexes (TEM)Ribosomes: Protein Factories•Ribosomes are particles made of ribosomal RNA and protein•Ribosomes carry out protein synthesis in two locations:–In the cytosol (free ribosomes)–On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes)Fig. 6-11CytosolEndoplasmic reticulum (ER)Free ribosomesBound ribosomesLarge subunitSmall subunitDiagram of a ribosomeTEM showing ER and ribosomes0.5 µmThe endomembrane system regulates protein traffic and performs metabolic functions in the cell•Components of the endomembrane system:–Nuclear envelope–Endoplasmic reticulum–Golgi apparatus–Lysosomes–Vacuoles–Plasma membrane•These components are either continuous or connected via transfer by vesicles1- Nuclear envelope- encloses nucleus•The nuclear envelope encloses the nucleus, separating it from the cytoplasm•The nuclear membrane is a double membrane; each membrane consists of a lipid bilayer2- The Endoplasmic Reticulum: Biosynthetic Factory•The endoplasmic reticulum (ER) accounts for more than half of the total membrane in many eukaryotic cells•The ER membrane is continuous with the nuclear envelope•There are two distinct regions of ER:–Smooth ER, which lacks ribosomes–Rough ER, with ribosomes studding its surfaceFunctions of Smooth and Rough ER•The smooth ER1. Synthesizes lipids 3.