3CytoplasmCytoplasmic OrganellesMitochondriaSlide 5RibosomesEndoplasmic Reticulum (ER)Slide 8Rough ERSmooth ERGolgi ApparatusSlide 12LysosomesEndomembrane SystemSlide 15Slide 16PeroxisomesCytoskeletonMicrofilamentsCellular ExtensionsSlide 21Slide 22Slide 23NucleusSlide 25Nuclear EnvelopeSlide 27NucleoliChromatinSlide 30Cells: The Living Units: Part CLocated between plasma membrane and nucleusCytosol◦Water with solutes (protein, salts, sugars, etc.)Cytoplasmic organelles◦Metabolic machinery of cellInclusions◦Granules of glycogen or pigments, lipid droplets, vacuoles, and crystalsMembranous◦Mitochondria◦Peroxisomes◦Lysosomes◦Endoplasmic reticulum◦Golgi apparatusNonmembranous◦Cytoskeleton ◦Centrioles ◦RibosomesDouble-membrane structure with shelflike cristaeProvide most of cell’s ATP via aerobic cellular respirationContain their own DNA and RNACopyright © 2010 Pearson Education, Inc.Figure 3.17EnzymesMatrixCristaeMitochondrial DNARibosomeOuter mitochondrial membraneInner mitochondrial membrane(b)(a)(c)Granules containing protein and rRNASite of protein synthesisFree ribosomes synthesize soluble proteins Membrane-bound ribosomes (on rough ER) synthesize proteins to be incorporated into membranes or exported from the cellInterconnected tubes and parallel membranes enclosing cisternaeContinuous with nuclear membraneTwo varieties:◦Rough ER◦Smooth ERCopyright © 2010 Pearson Education, Inc.Figure 3.18aNuclearenvelopeRibosomesRough ERSmooth ER(a) Diagrammatic view of smooth and rough ERExternal surface studded with ribosomesManufactures all secreted proteinsSynthesizes membrane integral proteins and phospholipidsTubules arranged in a looping networkEnzyme (integral protein) functions:◦In the liver — lipid and cholesterol metabolism, breakdown of glycogen, and, along with kidneys, detoxification of drugs, pesticides, and carcinogens ◦Synthesis of steroid-based hormones ◦In intestinal cells—absorption, synthesis, and transport of fats◦In skeletal and cardiac muscle — storage and release of calciumStacked and flattened membranous sacsModifies, concentrates, and packages proteins and lipidsTransport vessels from ER fuse with convex cis face of Golgi apparatusProteins then pass through Golgi apparatus to trans faceSecretory vesicles leave trans face of Golgi stack and move to designated parts of cellCopyright © 2010 Pearson Education, Inc.Figure 3.20 Protein-containing vesicles pinch off rough ERand migrate to fuse with membranes ofGolgi apparatus. Proteins aremodified withinthe Golgi compartments. Proteins arethen packagedwithin differentvesicle types, depending ontheir ultimatedestination.Plasmamem-braneSecretion byexocytosisVesicle becomeslysosomeGolgiapparatus Rough ERERmembranePhagosomeProteins incisternaPathway B:Vesicle membraneto be incorporatedinto plasmamembranePathway A:Vesicle contentsdestined for exocytosisExtracellular fluidSecretoryvesiclePathway C:Lysosome containing acid hydrolaseenzymes132Spherical membranous bags containing digestive enzymes (acid hydrolases)Digest ingested bacteria, viruses, and toxinsDegrade nonfunctional organellesBreak down and release glycogenBreak down bone to release Ca2+Destroy cells in injured or nonuseful tissue (autolysis)Overall function◦Produce, store, and export biological molecules◦Degrade potentially harmful substancesCopyright © 2010 Pearson Education, Inc.Figure 3.22GolgiapparatusTransportvesiclePlasmamembraneVesicleSmooth ERRough ERNuclear envelopeLysosomeNucleusPLAYPLAYAnimation: Endomembrane SystemMembranous sacs containing powerful oxidases and catalasesDetoxify harmful or toxic substancesNeutralize dangerous free radicals (highly reactive chemicals with unpaired electrons)Elaborate series of rods throughout cytosol◦Microtubules ◦Microfilaments ◦Intermediate filamentsDynamic actin strands attached to cytoplasmic side of plasma membraneInvolved in cell motility, change in shape, endocytosis and exocytosisCilia and flagella◦Whiplike, motile extensions on surfaces of certain cells◦Contain microtubules and motor molecules◦Cilia move substances across cell surfaces◦ Longer flagella propel whole cells (tail of sperm)PLAYPLAYAnimation: Cilia and FlagellaCopyright © 2010 Pearson Education, Inc.Figure 3.27(a) Phases of ciliary motion.(b) Traveling wave created by the activity ofmany cilia acting together propels mucusacross cell surfaces.Power, orpropulsive,strokeLayer of mucusCell surfaceRecovery stroke, whencilium is returning to itsinitial position1 2 3 4 5 6 7Microvilli◦Fingerlike extensions of plasma membrane◦Increase surface area for absorption◦Core of actin filaments for stiffeningCopyright © 2010 Pearson Education, Inc.Figure 3.28MicrovillusActinfilamentsTerminalwebGenetic library with blueprints for nearly all cellular proteinsResponds to signals and dictates kinds and amounts of proteins to be synthesizedMost cells are uninucleateRed blood cells are anucleateSkeletal muscle cells, bone destruction cells, and some liver cells are multinucleateCopyright © 2010 Pearson Education, Inc.Figure 3.29aChromatin (condensed)Nuclear envelopeNucleusNuclear poresNucleolusCisternae of rough ER(a)Double-membrane barrier containing poresOuter layer is continuous with rough ER and bears ribosomesInner lining (nuclear lamina) maintains shape of nucleusPore complex regulates transport of large molecules into and out of nucleusCopyright © 2010 Pearson Education, Inc.Figure 3.29bNucleusNuclearporesFractureline of outermembraneNuclear pore complexes.Each pore is ringed byprotein particles.Surface of nuclear envelope.Nuclear lamina. The netlikelamina composed of inter-mediate filaments formed bylamins lines the inner surfaceof the nuclear envelope.(b)Dark-staining spherical bodies within nucleusInvolved in rRNA synthesis and ribosome subunit assemblyThreadlike strands of DNA (30%), histone proteins (60%), and RNA (10%)Arranged in fundamental units called nucleosomesCondense into barlike bodies called chromosomes when the cell starts to divideCopyright © 2010 Pearson Education, Inc.Figure 3.30Metaphasechromosome(at midpointof cell division)Nucleosome (10-nm diameter; eight histone proteins wrapped by two winds of the DNA double helix)Linker DNAHistones(a)(b)1 DNA doublehelix (2-nm diameter)2 Chromatin(“beads on a