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CHAPTER 3 Microbiology With Diseases by Taxonomy PowerPoint® Lecture Slides Second Edition PART A 3 Cell Structure and Function Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Microbiology Cell structures and functions Growth Reproduction Responsiveness Metabolism Table 3-1 Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Processes of Life Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.1 - Overview 1 Prokaryotes Do not have membrane surrounding their DNA; no nucleus Lack various internal structures bound with phospholipid membranes Small; ~1.0 µm in diameter Simple structure Comprised of bacteria and archaea Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Table 3.5 Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Eukaryotes Have membrane surrounding DNA; have nucleus Have internal membrane-bound organelles Are larger; 10-100 µm in diameter Have more complex structure Comprised of algae, protozoa, fungi, animals, and plants Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.2 - Overview 2 Cocci Neisseria gonorrhea Gram negative S. pneumoniae Gram positive S. pyogenes S. aureus Gram positive Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.3 Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Spiral bacilli (rods) Escherichia coli Gram negative Vibrio cholerae Gram negative Bacillus cereus Gram positive B. anthracis Treponema pallidum G – syphilis Borrelia burgdorferii GLyme Disease Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 3 Axial filament External Structures of Prokaryotic Cells Glycocalyces Flagella Fimbriae and pili Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Glycocalyces Gelatinous, sticky substance surrounding the outside of the cell Composed of polysaccharides, polypeptides, or both Two types Capsule Slime layer Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Capsule Composed of organized repeating units of organic chemicals Firmly attached to cell surface Protects cells from drying out May prevent bacteria from being recognized and destroyed by host Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 4 Slime Layer Flagella Loosely attached to cell surface Water soluble Protects cells from drying out Sticky layer that allows prokaryotes to attach to surfaces Are responsible for movement Have long structures that extend beyond cell surface Not all prokaryotes have flagella Serotypes: E. coli O157:H7 Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Flagellar Arrangements Axial filament Treponema pallidum Peritrichous Borrelia burgdorferi Single polar Tufted polar Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.6 - Overview Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.7 - Overview 5 Motility http://www.cellsalive.com Bacterial Movement Chemotaxis/phototaxis PLAY Animation: Bacterial Motility Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.8 Fimbriae and Pili Nonmotile extensions Fimbriae Sticky, proteinaceous, bristlelike projections Used by bacteria to adhere to one another, to hosts, and to substances in environment May be hundreds per cell and are shorter than flagella Important function in biofilms Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Pili Long hollow tubules composed of pilin Longer than fimbriae but shorter than flagella Bacteria typically only have one or two per cell Join two bacterial cells and mediate the transfer of DNA from one cell to another (conjugation) Also known as conjugation pili or sex pili Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 6 Prokaryotic Cell Wall Prokaryote cell wall Provides structure and shape and protects cell from osmotic forces Assists some cells in attaching to other cells or in eluding antimicrobial drugs Animal cells do not have; can target cell wall of bacteria with antibiotics Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Bacterial Cell Wall Most have cell wall composed of peptidoglycan; a few lack a cell wall entirely Peptidoglycan composed of sugars, NAG, and NAM tetrapeptide bridges Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Cell walls Scientists describe two basic types of bacterial cell walls: gram-positive and gram-negative G- G+ G-Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings G+ http://www.ppws.vt.edu/~sforza/prokarote/cell_walls.html Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 7 G+ cell wall Gram-Positive Cell Wall Relatively thick layer of peptidoglycan teichoic acids Retains crystal violet dye in Gram staining procedure; appear purple Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Gram-Negative Cell Walls E. coli O157:H7 Have only a thin layer of peptidoglycan Bilayer membrane outside the peptidoglycan contains phospholipids, proteins, and lipopolysaccharide (LPS) May be impediment to the treatment of disease Following Gram staining procedure, cells appear pink Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 8 LPS and periplasm Bacterial Cell Walls LPS; lipopolysaccharide (union of lipid with sugar) Also known as endotoxin Lipid portion known as lipid A Dead cells release lipid A when cell wall disintegrates May trigger fever, vasodilation, inflammation, shock, and blood clotting Can be released when antimicrobial drugs kill bacteria Periplasm located between outer membrane and cell membrane Contains peptidoglycan and periplasm Contains water, nutrients, and substances secreted by the cell, such as digestive enzymes and proteins involved in transport Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Cell walls Figure 3.13b Archael Cell Walls Scientists describe two basic types of bacterial cell walls: gram-positive and gram-negative G- G+ G-- Do not have peptidoglycan Cell walls contain variety of specialized polysaccharides and proteins Gram-positive archaea stain purple Gram-negative archaea stain pink G+ http://www.ppws.vt.edu/~sforza/prokarote/cell_walls.html Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 9 Phospholipid Bilayer of Cytoplasmic Membrane Prokaryotic Cytoplasmic Membrane Referred to as phospholipid bilayer; composed of lipids and associated proteins Approximately half the membrane is composed of proteins that act as recognition proteins, enzymes, receptors, carriers, or channels Integral proteins Peripheral proteins Glycoproteins Fluid mosaic model describes current understanding of membrane structure Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.14 Control of Substances Across Cytoplasmic Membrane Naturally impermeable to most substances Proteins allow substances to cross membrane Occurs by passive or active processes Maintains a concentration gradient and electrical gradient Chemicals concentrated on one side of the membrane or the other Voltage exists across the membrane Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Passive Processes of Transport Diffusion Facilitated diffusion Osmosis Isotonic solution Hypertonic solution Hypotonic solution Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 10 Effects of Solutions on Organisms Cell wall disruption G+; lysozyme (or penicillin): protoplast G-; lysozyme; spheroplast http://www.cellsalive.com Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Penicillin discovered Figure 3.18 Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Penicillin Effects http://www.cellsalive.com http://www.cellsalive.com Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 11 Active Processes of Transport Active Transport Utilizes permease proteins and expends ATP Group Translocation Substance chemically modified during transport PLAY Nuclear region One circular chromosome: nucleod Plasmid: small circular DNA outside of chromosome Animation: Membrane Transport Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Ribosome Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Inclusions Reserve deposits Volutin (Polyphosphates): Corynebacterium diphtheria Sulfur granules: Thiobacillus Carboxysomes (enzyme for photosynthesis): Cyanobacteria Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 12 Cytoplasm of Prokaryotes Endospores Cytosol – liquid portion of cytoplasm Inclusions – may include reserve deposits of chemicals Ribosomes – sites of protein synthesis Cytoskeleton – plays a role in forming the cell’s basic shape Some bacterial cells produce dormant form called endospore Germination Dormant form; NOT reproductive Resists heating, freezing, desiccation, chemicals and radiation Genera Bacillus and Clostridium G+ rods Spore stain Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Endospore stain Endospore Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.22 - Overview Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 13 Eukaryotic cell External Structure of Eukaryotic Cells Glycocalyces Never as organized as prokaryotic capsules Helps anchor animal cells to each other Strengthens cell surface Provides protection against dehydration Function in cell-to-cell recognition and communication Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Eukaryotic Cell Walls Fungi, algae, plants, and some protozoa have cell walls but no glycocalyx Composed of various polysaccharides Cellulose found in plant cell walls Fungal cell walls composed of cellulose, chitin, and/or glucomannan Algal cell walls composed of cellulose, proteins, agar, carrageenan, silicates, algin, calcium carbonate, or a combination of these Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Eukaryotic Cytoplasmic Membrane All eukaryotic cells have cytoplasmic membrane Is a fluid mosaic of phospholipids and proteins Contains steroid lipids to help maintain fluidity Controls movement into and out of cell Uses diffusion, facilitated diffusion, osmosis, and active transport Performs endocytosis; phagocytosis if solid substance and pinocytosis if liquid substance Exocytosis enables substances to be exported from cell Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings 14 Endocytosis Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.26 - Overview Eukaryotes – outer structures and Nonmembranous Organelles Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.35 Eukaryotic Flagella Flagella: “9 + 2” arrangement of microtubules in all flagellated eukaryotes Cilia Ribosomes: Composed of 60S and 40S subunits Cytoskeleton Centrioles and centrosome Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.27a 15 Cytoplasm of Eukaryotes – Membranous Organelles Endosymbiotic Theory Eukaryotes formed from union of small aerobic prokaryotes with larger anaerobic prokaryotes; smaller prokaryotes became internal parasites Nucleus Endoplasmic reticulum Golgi body Lysosomes, peroxisomes, vacuoles, and vesicles Mitochondria Chloroplasts Parasites lost ability to exist independently; retained portion of DNA, ribosomes, and cytoplasmic membranes Larger cell became dependent on parasites for aerobic ATP production Aerobic prokaryotes evolved into mitochondria Similar scenario for origin of chloroplasts Not universally accepted Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Table 3.4 Copyright © 2007 Pearson Education, Inc. publishing as Benjamin Cummings Table 3.5 16
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