CHAPTER 2 The Organization of CellBasic features of all cells:Plasma membraneSemifluid substance called cytosolChromosomes (carry genes): DNA and RNARibosomes (make proteins)Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin CummingsThe Cell: The Basic Unit of LifeFig. 6-2 10 m1 m0.1 m1 cm1 mm100 m10 m1 m100 nm10 nm1 nm0.1 nmAtomsSmall moleculesLipidsProteinsRibosomesVirusesSmallest bacteriaMitochondrionNucleusMost bacteriaMost plant and animal cellsFrog eggChicken eggLength of some nerve and muscle cellsHuman heightUnaided eyeLight microscopeElectron microscopeMicroscopyRobert HookeA.V. LeeuwenhookeThe Cell: The Basic Unit of Life Microscopes are needed to visualize most cells Eggs notable exception Light or electron microscopes allow observation of greater detail than light microscopes do. Light microscopes 200nm 1,000 foldMagnification ResolutionTwo 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-DTransmission electron microscopes (TEMs) focus a beam of electrons through a specimenTEMs are used mainly to study the internal structure of cellsCopyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin CummingsFig. 6-4(a) Scanning electron microscopy (SEM)TECHNIQUERESULTS(b) Transmission electron microscopy (TEM)CiliaLongitudinal section of ciliumCross section of cilium 1 m1 mCategories of CellsThe basic structural and functional unit of every organism is one of two types of cells: prokaryotic or eukaryoticOnly organisms of the domains Bacteria and Archaea consist of prokaryotic cellsProtists, fungi, animals, and plants all consist of eukaryotic cellsCategories of CellsEukaryoticmembranous organelles nucleus, ER, Golgi, vesicles, mitochondria, plastidscytoskeleton actin, myosin, tubulinProkaryoticcircular chromosomeno membranous organellesProkaryotic Cell Features Prokaryotic cell organization is characteristic of the kingdoms Eubacteria and Archaebacteria. Prokaryotic cells lack internal compartments.Prokaryotic cellsare characterized by havingNo nucleusDNA in an unbound region called the nucleoidNo membrane-bound organellesCytoplasm bound by the plasma membraneFig. 6-6FimbriaeNucleoidRibosomesPlasma membraneCell wallCapsuleFlagellaBacterial chromosome(a) A typical rod-shaped bacterium(b) A thin section through the bacterium Bacillus coagulans (TEM)0.5 mProkaryotic OrganellesRibosomeLarge free and bound ribosomes; smooth and rough ER2. Describe the structure and function of the components of the endomembrane system3. Briefly explain the role of mitochondria, chloroplasts, and peroxisomes4. Describe the functions of the cytoskeleton5. Describe the structure of a plant cell wall6. Describe the structure and roles of the extracellular matrix in animal cells7. Describe the intercellular junctions