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Ch 4 Functional anatomy of Bacteria and other Microbes
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Or The differences between Eukaryotic and Prokaryotic cells
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Q&A Penicillin was called a “miracle drug” because it doesn’t harm human cells. Why doesn’t it?
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Proks and euks are similar in chemical composition and reaction Proks lack membrane bound organelles Only Proks have peptidoglycan Euks have membrane bound organelles Euks have paired chromosomes Euks have histones
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Nick sees the difference mainly in information and structural capacity Proks lack membrane-enclosed organelles Euks are like a 2mhz 100gb home computer Proks are like a calculator Human genome 4x10 9 E. coli 4x10 6
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The prokaryote Unicellular Multiply by binary fission Differentiated by –Morphology –Chemical composition –Nutritional requirements –Biochemical activates –Sources of energy –Other tests
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Size 0.2 to 2um in diameter 2-8um in length In biological systems there are always exceptions these are general sizes.
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Shape
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Coccus –Diplococci –Streptococci –Staphylococci Bacillus Spiral Other pleomorphic shapes
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Basic components of a bacterial cell fig 4.6
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Parts not seen Glycocalyx –Capsule –Slime layer –Extracellular polysaccharide Function Toxicity Protect from phagocytosis Allow adherence Reduce water loss Collect nutrients
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Flagella: long filamentous appendages with filament, hook and basal body Used in movement Can present taxis –Negative –Positive Monotrichous Peritrichous Flagellar H protein acts as an antigen E.c O157:H7 Flagellin
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Flagella Arrangement Figure 4.7
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Fimbriae/pili Shorter and less complex than flagella Helps adhere to surfaces Used for sex and communication
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Cell wall Major difference between eukaryotic and prok orgs. Surrounds plasma membrane provides protection Peptidoglycan –Polymer of NAG NAM Short amino acid chain Production inhibited by antibiotics Prevents osmotic damage Damage to cw is almost always lethal except
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Gram Positives have large cell wall and Teichoic acids
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Gram neg have lipopolysaccharide
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Figure 4.12 Peptidoglycan Polymer of disaccharide: –N- acetylglucosamine (NAG) –N-acetylmuramic acid (NAM)
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Figure 4.13a Peptidoglycan in Gram-Positive Bacteria
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Figure 4.6 The Cell Wall Prevents osmotic lysis 4-7Differentiate protoplast, spheroplast, and L form. Made of peptidoglycan (in bacteria) Linked by polypeptides
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Gram-Positive Bacterial Cell Wall Figure 4.13b
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Gram-Negative Bacterial Cell Wall Figure 4.13c
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Thick peptidoglycan Teichoic acids Gram-positive Cell Wall Figure 4.13b–c Thin peptidoglycan Outer membrane Periplasmic space Gram-positive Cell Wall
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Gram neg Lipoprotein phospholipid outer membrane surrounding a thin peptidoglycan Makes gram neg resistant to –Phagocytosis –Antibiotics –Chemical reactions –Enzymes (lysozyme) –Has lipid A endotoxin –O polysaccaride antigen O157:H7 E.c.
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Gram-Negative Outer Membrane Figure 4.13c
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How the gram stain works to differentiate between G+ and G-
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The Gram Stain Table 4.1 (a) Gram-Positive(b) Gram-Negative
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The Gram Stain Mechanism Crystal violet-iodine crystals form in cell Gram-positive –Alcohol dehydrates peptidoglycan –CV-I crystals do not leave Gram-negative –Alcohol dissolves outer membrane and leaves holes in peptidoglycan –CV-I washes out
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2-ring basal body Disrupted by lysozyme Penicillin sensitive Gram-Positive Cell Wall Figure 4.13b–c 4-ring basal body Endotoxin Tetracycline sensitive Gram-Negative Cell Wall
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Nontypical cell walls Mycoplasma (acid fast) do not have ppt containing cell wall. Archaea contain another chemical called pseudomurein
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Figure 24.8 Atypical Cell Walls Acid-fast cell walls –Like gram-positive –Waxy lipid (mycolic acid) bound to peptidoglycan –Mycobacterium –Nocardia
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Atypical Cell Walls Mycoplasmas –Lack cell walls –Sterols in plasma membrane Archaea –Wall-less or –Walls of pseudomurein (lack NAM and D -amino acids)
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Damage to the Cell Wall Lysozyme digests disaccharide in peptidoglycan Penicillin inhibits peptide bridges in peptidoglycan Protoplast is a wall-less cell Spheroplast is a wall-less gram-positive cell –Protoplasts and spheroplasts are susceptible to osmotic lysis L forms are wall-less cells that swell into irregular shapes
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Plasma membrane Defines the living and nonliving parts of the cell –Everything on the inside is living –Everything on the outside is not living Is selectively permeable Workspace for enzymes of metabolic reactions
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Plasma Membrane Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane proteins Figure 4.14b
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PM Workspace –Nutrient breakdown –Energy production –Photosynthesis –Afforded by mesosomes which are regular infoldings of the plasma membrane Weaknesses: destroyed by actions of alcohols, detergents and polymyxins
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Membrane is as viscous as olive oil. Proteins move to function Phospholipids rotate and move laterally Fluid Mosaic Model Figure 4.14b
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Damage to the membrane by alcohols, quaternary ammonium (detergents) and polymyxin antibiotics causes leakage of cell contents. Plasma Membrane
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Figure 4.17a Movement of Materials across Membranes Simple diffusion: Movement of a solute from an area of high concentration to an area of low concentration
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Figure 4.17b-c Movement of Materials across Membranes Facilitated diffusion: Solute combines with a transporter protein in the membrane
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ANIMATION Passive Transport: Principles of Diffusion ANIMATION Passive Transport: Special Types of Diffusion Movement of Materials across Membranes
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Figure 4.18a 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 Osmotic pressure: The pressure needed to stop the movement of water across the membrane
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Figure 4.17d Movement of Materials across Membranes Through lipid layer Aquaporins (water channels)
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Figure 4.18a–b The Principle of Osmosis
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Figure 4.18c–e The Principle of Osmosis
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ANIMATION Active Transport: Overview ANIMATION Active Transport: Types Movement of Materials across Membranes Active transport: Requires a transporter protein and ATP Group translocation: Requires a transporter protein and PEP
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Cytoplasm's The liquid component of the cell within the PM Mostly water, dissolved ions, DNA ribosomes and inclusions Concept of homeostasis
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Nuclear area Contains the bacterial chromosome Bacteria may also have plasmids with up to 25% of the genetic materials
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Ribosomes Figure 4.6a
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Ribosomes Figure 4.19
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Inclusions Typically reserve deposits of excess materials like inorganic phosphate Polysaccharide granules Lipids Sulfur Gas iron
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Figure 4.19 The Prokaryotic Ribosome Protein synthesis 70S –50S + 30S subunits
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Figure 4.20 Magnetosomes
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Inclusions Metachromatic granules (volutin) Polysaccharide granules Lipid inclusions Sulfur granules Carboxysomes Gas vacuoles Magnetosomes Phosphate reserves Energy reserves Ribulose 1,5-diphosphate carboxylase for CO 2 fixation Protein-covered cylinders Iron oxide (destroys H 2 O 2 )
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Endospores Resting and waiting stage Resistant to drying and other harsh conditions
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The Eukaryotic cell
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Comparison Flagella and cilia tubulin (9/2) arrangement Cell wall of different materials Glycocalyx Plasma membrane
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organelles Nucleus ER 80s ribosomes Golgi complex Lysozymes Vacuoles Mitochondria Chloroplasts Peroxisomes
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Organelles 4-18Define organelle. 4-19 Describe the functions of the nucleus, endoplasmic reticulum, Golgi complex, lysosomes, vacuoles, mitochondria, chloroplasts, peroxisomes, and centrosomes.
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Organelles Nucleus: Contains chromosomes ER: Transport network Golgi complex: Membrane formation and secretion Lysosome: Digestive enzymes Vacuole: Brings food into cells and provides support
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Organelles Mitochondrion: Cellular respiration Chloroplast: Photosynthesis Peroxisome: Oxidation of fatty acids; destroys H 2 O 2 Centrosome: Consists of protein fibers and centrioles
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Figure 4.24 The Eukaryotic Nucleus
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Figure 4.24a–b The Eukaryotic Nucleus
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Figure 4.25 Rough Endoplasmic Reticulum
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Figure 4.25a Detailed Drawing of Endoplasmic Reticulum
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Figure 4.25b Micrograph of Endoplasmic Reticulum
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Figure 4.26 Golgi Complex
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Figure 4.22b Lysosomes and Vacuoles
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Figure 4.27 Mitochondria
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Figure 4.28 Chloroplasts
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Figure 4.28a Chloroplasts
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Figure 4.28b Chloroplasts
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Figure 4.22b Peroxisome and Centrosome
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Not membrane-bound: –RibosomeProtein synthesis –CentrosomeConsists of protein fibers and centrioles –CentrioleMitotic spindle formation Eukaryotic Cell
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Evolution of eukaryotes Endosymbiotic theory
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Membrane activity Diffusion Osmosis Passive diffusion Facilitated diffusion Active transport Know the relationships
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Active transport of substances requires a transporter protein and ATP. Group translocation of substances requires a transporter protein and PEP. Movement Across Membranes
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