Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 4 Functional Anatomy of Prokaryotic and Eukaryotic Cells Copyright © 2010 Pearson Education, Inc. Lectures prepared by Christine L. Case Prokaryotic and Eukaryotic Cells Prokaryote comes from the Greek words for prenucleus. Bacteria and Archaea are the Prokaryotes Eukaryote comes from the Greek words for true nucleus. All other cellular organisms are Eukaryotes. Fungi (molds, yeast) Protista (unicellular algae and protozoans) Plants Animals Copyright © 2010 Pearson Education, Inc. Prokaryote One circular chromosome, not enclosed in a membrane-found in the Nucleoid region of the cell Only non-histone proteins with the DNA No membrane-enclosed organelles Peptidoglycan cell walls if Bacteria Pseudomurein cell walls if Archaea Binary fission form of cell division Copyright © 2010 Pearson Education, Inc. Eukaryote Multiple chromosomes, in nuclear membraneThe Nucleus. -Histones and nonhistones with DNA Membrane-enclosed organelles Simple, polysaccharide cell walls Mitotic form of cell division with a ‘spindle’ Comparing Sizes: Animation comparing viruses, bacteria, eukaryotic cells http://www.cellsalive.com/howbig.htm Eukaryotic cells are highly compartmentalized. A large surface-to-volume ratio, as seen in smaller prokaryotic cells, means that nutrients can easily and rapidly reach any part of the cells interior. However, in the larger eukaryotic cell, the limited surface area when compared to its volume means nutrients cannot rapidly diffuse to all interior parts of the cell. That is why eukaryotic cells require a variety of specialized internal organelles to transport chemicals throughout the cell and carry out life functions (most of the things needed for a particular function are kept together in membranous structures rather than free-floating). Copyright © 2010 Pearson Education, Inc. Basic Shapes Bacillus (rod-shaped) Coccus (spherical) Spiral Spirillum Vibrio Spirochete Copyright © 2010 Pearson Education, Inc. Figures 4.1a, 4.2a, 4.2d, 4.4a, 4.4b, 4.4c Unusually Shaped Bacteria Copyright © 2010 Pearson Education, Inc. Figure 4.5a Unusually Shaped Bacteria Fig. 4.5b p. 79 Archaea,not Bacterium Copyright © 2010 Pearson Education, Inc. Figure 4.5b Arrangements Pairs: Diplococci, diplobacilli Clusters: Staphylococci Chains: Streptococci, streptobacilli Copyright © 2010 Pearson Education, Inc. Figures 4.1a, 4.1d, 4.2b, 4.2c The Structure of a Prokaryotic Cell Copyright © 2010 Pearson Education, Inc. Figure 4.6 Glycocalyx Outside cell wall Usually sticky (biofilms) Capsule: neatly organized Copyright © 2010 Pearson Education, Inc. Slime layer: unorganized and loose Extracellular polysaccharide allows cell to attach Capsules prevent phagocytosis Capsules were instrumental in determining that DNA was the genetic material (Fig. 8.24 p. 235) Figure 24.12 Transformation: Copyright © 2010 Pearson Education, Inc. Griffith discovers Transformation (1928) While working with encapsulated S strains and unencapsulated R strains of Streptococcus pneumonia (pneumococcus), Griffith observed that when heat-killed S forms and living R forms were injected into mice, the mice died. When he isolated living bacteria from the dead mice, they had a capsule. The R strain had been transformed into an S strain! Transformation is a common procedure in today's genetic engineering labs. Copyright © 2010 Pearson Education, Inc. Oswald Avery, Colin MacLeod, and Maclyn (1944) determined that the ‘transforming’ (genetic/hereditary) molecule was . Copyright © 2010 Pearson Education, Inc. Arrangements of Bacterial Flagella Copyright © 2010 Pearson Education, Inc. Figure 4.7 Axial Filaments Also called endoflagella or periplasmic flagella In spirochetes only The spirochetes are a … unique group of bacteria. This phylum contains not only many medically important species such as Treponema pallidum and Borrelia burgdorferi but others live inside arthropods such as termites and some that are free-living and reside in soil and water. http://jb.asm.org/cgi/content/full/182/23/6698 Individual AF can be anchored at one end or the other of a cell. Rotation causes the cell to move. Copyright © 2010 Pearson Education, Inc. Figure 4.10a Fimbriae and Pili: Made of a different protein (pilin) than flagella and are shorter, thinner, straighter. Fimbriae allow attachment: Important for some diseases (gonorrhea and E.coli 0157:H7) and biofilms. Copyright © 2010 Pearson Education, Inc. Figure 4.11 The Cell Wall (Fig. 4.13 p. 86) Prevents osmotic lysis In bacteria: Made of peptidoglycan Gram Positive vs. Gram Negative Cell Walls Copyright © 2010 Pearson Education, Inc. Figure 4.6 Peptidoglycan in Gram Positive Bacteria Linked by polypeptides Copyright © 2010 Pearson Education, Inc. Figure 4.13a Gram Positive Cell Wall Many layers of peptidoglycan Copyright © 2010 Pearson Education, Inc. Gram positive Cell Wall Gram negative Cell Wall Thick peptidoglycan Teichoic acids Copyright © 2010 Pearson Education, Inc. Thin peptidoglycan Outer membrane Periplasmic space No Teichoic acids Figure 4.13b–c Gram-Negative Cell Wall Copyright © 2010 Pearson Education, Inc. Figure 4.13c Gram Negative Periplasm The space between the plasma membrane and the outer membrane Gel-like fluid containing digestive enzymes and transport proteins The periplasm also contains the one/few layer(s) of peptidoglycan (bonded to lipoproteins in the outer membrane) In Spirochetes, the axial filaments are found in the periplasm Copyright © 2010 Pearson Education, Inc. Gram-Negative Outer Membrane Protection from lysozyme, some detergents, phagocytes, complement (in blood-lyses cells and promotes phagocytosis), and certain antibiotics Contains Lipopolysaccharide: Important parts of LPS O polysaccharide antigen can be used to distinguish between serovars (strains) e.g., E. coli O157:H7 Lipid A is an endotoxin (Released when the bacterium dies- causes septic shock) Also contains Porins- Proteins that form channels through the outer membrane for nutrient transport Copyright © 2010 Pearson Education, Inc. The Gram Stain (a) Gram-Positive Copyright © 2010 Pearson Education, Inc. (b) Gram-Negative Table 4.1 Gram-Positive Cell Wall Gram-Negative Cell Wall 2-ring basal body (flagella) Disrupted by lysozyme (destroys bonds connecting NAG-NAM) Penicillin sensitive 4-ring basal body (flagella) Endotoxin Tetracycline sensitive (Penetrates the OM better-interferes with protein synthesis) Copyright © 2010 Pearson Education, Inc. Figure 4.13b–c Atypical Cell Walls Acid-fast cell walls Difficult to stain, but carbolfuchsin and heat will stain it red Waxy lipid (mycolic acid) bound to peptidoglycan (if mycolic acid removed, will be Gram +) Mycobacterium (branching filaments) Tuberculosis Leprosy Copyright © 2010 Pearson Education, Inc. Figure 24.8 Atypical Cell Walls Mycoplasmas: smallest living organism that can grow/reproduce outside another living cell Lack cell walls Sterols in plasma membrane believed to aid in preventing lysis Archaea Wall-less or Walls containing pseudomurein (lack NAM and D-amino acids) Copyright © 2010 Pearson Education, Inc. The Plasma Membrane Copyright © 2010 Pearson Education, Inc. Figure 4.14a The Plasma Membrane Fig. 4.14 p. 90 Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane Proteins Copyright © 2010 Pearson Education, Inc. Figure 4.14b Fluid Mosaic Model Membrane is as viscous as olive oil Proteins move to function Phospholipids rotate and move laterally Copyright © 2010 Pearson Education, Inc. Figure 4.14b The Plasma Membrane Selective permeability allows passage of some molecules Enzymes for ATP production Photosynthetic pigments on foldings called chromatophores or thylakoids Copyright © 2010 Pearson Education, Inc. Chromatophores Copyright © 2010 Pearson Education, Inc. Figure 4.15 The Plasma Membrane Damage to the membrane by alcohols, quaternary ammonium (detergents), and polymyxin antibiotics causes leakage of cell contents ANIMATION Membrane Structure ANIMATION Membrane Permeability Copyright © 2010 Pearson Education, Inc. Movement of Materials across Membranes Simple diffusion: Movement of a solute from an area of high concentration to an area of low concentration Copyright © 2010 Pearson Education, Inc. Figure 4.17a Movement of Materials across Membranes Facilitated diffusion: Solute combines with a transporter protein in the membrane Copyright © 2010 Pearson Education, Inc. Figure 4.17b-c Movement of Materials across Membranes Osmosis: The movement of water across a selectively permeable membrane from an area of high water to an area of lower water concentration Copyright © 2010 Pearson Education, Inc. Figure 4.18a Movement of Materials across Membranes Through lipid layer Aquaporins (water channels) Copyright © 2010 Pearson Education, Inc. Figure 4.17d The Principle of Osmosis Fig. 4.18 p. 93 Copyright © 2010 Pearson Education, Inc. Figure 4.18c–e Movement of Materials across Membranes Active transport: Requires a transporter protein and ATP Group translocation: Requires a transporter protein and PEP ANIMATION Active Transport: Types ANIMATION Active Transport: Overview Copyright © 2010 Pearson Education, Inc. Archaeal vs. Bacterial/Eukaryal Plasma Membranes Archaeal cell membranes are chemically different from the membranes of all other living things. Copyright © 2010 Pearson Education, Inc. Cytoplasm The substance inside the plasma membrane Copyright © 2010 Pearson Education, Inc. Figure 4.6 The Nucleoid Bacterial chromosome Plasmids Copyright © 2010 Pearson Education, Inc. Figure 4.6 Ribosomes Copyright © 2010 Pearson Education, Inc. Figure 4.6 The Prokaryotic Ribosome Protein synthesis 70S 50S + 30S subunits Copyright © 2010 Pearson Education, Inc. Figure 4.19 Inclusions: Reserves deposits; help maintain osmotic balance Metachromatic granules Polysaccharide granules Lipid inclusions Sulfur granules Carboxysomes Gas vacuoles Magnetosomes Copyright © 2010 Pearson Education, Inc. Phosphate reserves Energy reserves Energy reserves Energy reserves Ribulose 1,5-diphosphate carboxylase for CO2 fixation Protein-covered cylinders; allows aquatic cells to have the correct level of buoyancy needed to receive the appropriate amount of light/oxygen/nutrients Iron oxide (destroys H2O2) Magnetosomes Copyright © 2010 Pearson Education, Inc. Figure 4.20 Endospores Dormant Resistant to desiccation, hostile environments (cold, heat, chemicals), lack of nutrients Mostly specific Gram + bacteria Bacillus (anthrax), Clostridium (tetanus, botulism, gangrene) Sporulation: Endospore formation Germination: Return to vegetative state Copyright © 2010 Pearson Education, Inc. Endospores Figure 4.21b Copyright © 2010 Pearson Education, Inc. Sporulation and Germination Figure 4.21a Copyright © 2010 Pearson Education, Inc. The Eukaryotic Cell Figure 4.22a Copyright © 2010 Pearson Education, Inc. Flagella and Cilia Figure 4.23a-b Copyright © 2010 Pearson Education, Inc. The Cell Wall and Glycocalyx Cell wall Plants, algae, fungi Carbohydrates Cellulose, chitin, glucan, mannan Glycocalyx Carbohydrates extending from animal plasma membrane Bonded to proteins and lipids in membrane Copyright © 2010 Pearson Education, Inc. Q&A Penicillin was called a “miracle drug” because it doesn’t harm human cells. Why doesn’t it? Copyright © 2010 Pearson Education, Inc. The Plasma Membrane Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane proteins Sterols Glycocalyx carbohydrates Copyright © 2010 Pearson Education, Inc. The Plasma Membrane Selective permeability allows passage of some molecules Simple diffusion Facilitative diffusion Osmosis Active transport Endocytosis Phagocytosis: Pseudopods extend and engulf particles Pinocytosis: Membrane folds inward, bringing in fluid and dissolved substances Exocytosis: reverse of endocytosis Copyright © 2010 Pearson Education, Inc. Cytoplasm Copyright © 2010 Pearson Education, Inc. Table 4.2 Cytoplasm Cytoplasm membrane: Substance inside plasma and outside nucleus Cytosol: Fluid portion of cytoplasm Cytoskeleton: Microfilaments, intermediate filaments, microtubules Copyright © 2010 Pearson Education, Inc. Ribosomes in Eukaryotes Protein synthesis 80S Membrane-bound: Attached to ER Free: In cytoplasm 70S In chloroplasts and mitochondria Copyright © 2010 Pearson Education, Inc. Organelles Nucleus: Contains chromosomes ER: Transport network Golgi complex: Membrane formation and secretion Lysosome: Digestive enzymes Vesicles: Vacuole: Brings food into cells and provides support Copyright © 2010 Pearson Education, Inc. Organelles Mitochondrion: Cellular respiration Chloroplast: Photosynthesis Peroxisome: Oxidation of fatty acids; destroys H2O2 Centrosome: Consists of protein fibers and centrioles (Utilized for cell division) Copyright © 2010 Pearson Education, Inc. The Eukaryotic Nucleus Figure 4.24a–b Copyright © 2010 Pearson Education, Inc. Rough Endoplasmic Reticulum Figure 4.25 Copyright © 2010 Pearson Education, Inc. Micrograph of Endoplasmic Reticulum Figure 4.25b Copyright © 2010 Pearson Education, Inc. Vesicles and Golgi Complex Figure 4.26 Copyright © 2010 Pearson Education, Inc. Lysosomes: Made in the Golgi body. Contain digestive enzymes that degrade waste, invaders (bacteria), damaged cells and particles, larger molecules into needed smaller molecules, etc. Vacuoles: Storage (food, toxins, waste, water) Figure 4.22b Copyright © 2010 Pearson Education, Inc. Mitochondria Figure 4.27 Copyright © 2010 Pearson Education, Inc. Chloroplasts Figure 4.28 Copyright © 2010 Pearson Education, Inc. Peroxisome: Enzymes which function in normal metabolism and degrade toxins. Contain catalase to decompose H2O2 (Produced as a by-product during the metabolic reactions in the peroxisome). Centrosome: Produce microtubules needed for cell division and the cytoskeleton Figure 4.22b Copyright © 2010 Pearson Education, Inc. Endosymbiotic Theory Figure 10.2 Copyright © 2010 Pearson Education, Inc. Endosymbiotic Theory What are the fine extensions on this protozoan? Copyright © 2010 Pearson Education, Inc. Endosymbiotic Theory Copyright © 2010 Pearson Education, Inc.