Presentation on theme: "Chapter 4 Prokaryotic Cell"— Presentation transcript:
1Chapter 4 Prokaryotic Cell Functional Anatomy of Prokaryotic and Eukaryotic CellsBio 205
2Prokaryotic Cells Comparing Prokaryotic and Eukaryotic Cells Prokaryote comes from the Greek words for prenucleus.Eukaryote comes from the Greek words for true nucleus.
3Prokaryote Eukaryote Paired chromosomes, in nuclear membrane One circular chromosome, not in a membraneNo histonesNo organellesPeptidoglycan cell wallsBinary fissionPaired chromosomes, in nuclear membraneHistonesOrganellesPolysaccharide cell wallsMitotic spindle
7Glycocalyx Outside cell wall Usually sticky A capsule is neatly organizedA slime layer is unorganized & looseExtracellular polysaccharide allows cell to attachCapsules prevent phagocytosisFigure 4.6a, b
8Flagella Outside cell wall Made of chains of flagellin Attached to a protein hookAnchored to the wall and membrane by the basal bodyFigure 4.8
18Gram-Positive cell walls Teichoic acids:Lipoteichoic acid links to plasma membraneWall teichoic acid links to peptidoglycanMay regulate movement of cationsPolysaccharides provide antigenic variationFigure 4.13b
19Gram-Negative Outer Membrane Lipopolysaccharides, lipoproteins, phospholipids.Forms the periplasm between the outer membrane and the plasma membrane.Protection from phagocytes, complement, antibiotics.O polysaccharide antigen, e.g., E. coli O157:H7.Lipid A is an endotoxin.Porins form channels through membrane
20Gram Stain Mechanism Crystal violet-iodine crystals form in cell Gram-positiveAlcohol dehydrates peptidoglycanCV-I crystals do not leaveGram-negativeAlcohol dissolves outer membrane and leaves holes in peptidoglycanCV-I washes out
21Atypical Cell Walls Mycoplasmas Lack cell walls Sterols in plasma membraneArchaeaWall-less, orWalls of pseudomurein (lack NAM and D amino acids)
22Damage to Cell Walls Lysozyme digests disaccharide in peptidoglycan. Penicillin inhibits peptide bridges in peptidoglycan.Protoplast is a wall-less cell Gram-positive cell.Spheroplast is a wall-less Gram-negative cell.L forms are wall-less cells that swell into irregular shapes.Protoplasts and spheroplasts are susceptible to osmotic lysis.