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1 Dr. Alvin Fox. 2 Key Words ProkaryoticOuter membrane Eubacteria (Bacteria)Periplasmic space Archaebacteria(Archaea)Oxidative phosphorylation EukaryoticSpheroplast/protoplast.

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Presentation on theme: "1 Dr. Alvin Fox. 2 Key Words ProkaryoticOuter membrane Eubacteria (Bacteria)Periplasmic space Archaebacteria(Archaea)Oxidative phosphorylation EukaryoticSpheroplast/protoplast."— Presentation transcript:

1 1 Dr. Alvin Fox

2 2 Key Words ProkaryoticOuter membrane Eubacteria (Bacteria)Periplasmic space Archaebacteria(Archaea)Oxidative phosphorylation EukaryoticSpheroplast/protoplast PlasmidFlagella ChromosomeChemotaxis RibosomeAxial filament Peptidoglycan (murein, mucopeptide)Periplasmic binding protein Gram stainPermeases Gram negativeStorage Granules Gram positivePili (fimbriae) Cell envelopeCapsule (slime layer, glycocalyx) Cell membraneEndospore (spore) Cell wall

3 3 PROKARYOTES BACTERIAARCHAEA EUKARYOTES EUKARYOTES

4 4 Prokaryotes (Bacteria) Eubacter "True" bacteriaEubacter "True" bacteria – human pathogens – clinical or environmental – one kingdom Archaea Archaea – Environmental organisms – second kingdom

5 5 Eukaryotes Other cell-based life e.g.Other cell-based life e.g. –plants –animals –fungi

6 6 Prokaryotic Cell (versus Eukaryotic Cell) Not compartmentalizedNot compartmentalized Cell membranes lack sterols (e.g. cholesterol)Cell membranes lack sterols (e.g. cholesterol) Single circular chromosomeSingle circular chromosome RibosomesRibosomes - 70S - subunits 30S (16S rRNA)30S (16S rRNA) 50S (5S & 23S rRNA)50S (5S & 23S rRNA)

7 7 Bacteria versus Archaebacteria EubacteriaEubacteria –peptidoglycan (murein) –muramic acid ArchaebacteriaArchaebacteria –pseudomurein –no muramic acid

8 8 Bacteria versus Archaebacteria 16S rRNA16S rRNA –sequence different

9 9 Eukaryotic cellProkaryotic cell Gram + Gram - Cell wall Rough endoplasmic reticulum Mitochondria (e.g. animal) Nucleoid Nucleus Cell membrane Cytoplasm Flagellum Cell (inner) membraneOuter membrane Ribosomes Granule Cell wall Capsule Pili

10 10 Bacteria PlasmidsPlasmids Extra-chromosomal DNA multiple copy number coding - pathogenesis factors - antibiotic resistance factors bacterial replication

11 11 The Cell Envelope Gram Positive Gram Negative

12 12 Cytoplasm Oxidative phosphorylation occurs at cell membrane (since there are no mitochondria). Cell membrane The cell wall is outside of cell membrane – rigid, protecting cell from osmotic lysis. Cell Wall

13 13 GRAM POSITIVE GRAM NEGATIVE Cytoplasm Cytoplasm Lipoteichoic acid Peptidoglycan-teichoic acid Cytoplasmic membrane Inner (cytoplasmic) membrane Outer Membrane Lipopolysaccharide Porin Braun lipoprotein Periplasmic space

14 14 Outer Membrane Gram negative bacteria Gram negative bacteria major permeability barriermajor permeability barrier space between inner and outer membranespace between inner and outer membrane –periplasmic space  store degradative enzymes Gram positive bacteriaGram positive bacteria no periplasmic spaceno periplasmic space

15 15 GRAM NEGATIVE CELL ENVELOPE Cytoplasm Inner (cytoplasmic) membrane Outer Membrane (Major permeability barrier) Lipopolysaccharide Porin Braun lipoprotein Periplasmic space Degradative enzyme Periplasmic binding protein Permease

16 16 Cytoplasm Lipoteichoic acid Peptidoglycan-teichoic acid Cytoplasmic membrane GRAM POSITIVE CELL ENVELOPE Degradative enzyme

17 17 FLAGELLA Some bacteria are motileSome bacteria are motile Locomotory organelles- flagellaLocomotory organelles- flagella Taste environmentTaste environment Respond to food/poisonRespond to food/poison –chemotaxis

18 18 Flagella –embedded in cell membrane –project as strand –Flagellin (protein) subunits –move cell by propeller like action

19 19 Axial filaments –spirochetes –similar function to flagella –run lengthwise along cell –snake-like movement

20 20 Making Wall-less Forms Result from action of:Result from action of: –enzymes lytic for cell wall –antibiotics inhibiting peptidoglycan biosynthesis Usually non-viableUsually non-viable Wall-less bacteria that don’t replicate:Wall-less bacteria that don’t replicate: –spheroplasts (with outer membrane) –protoplasts (no outer membrane). Wall-less bacteria that replicateWall-less bacteria that replicate –L forms

21 21 Naturally Wall-less Genus MycoplasmaMycoplasma

22 22 Pili (fimbriae) hair-like projections of the cell hair-like projections of the cell sexual conjugation sexual conjugation adhesion to host epithelium adhesion to host epithelium

23 23 Capsules and slime layers outside cell envelopeoutside cell envelope well defined: capsulewell defined: capsule not defined: slime layer or glycocalyxnot defined: slime layer or glycocalyx usually polysaccharideusually polysaccharide often lost during in vitro cultureoften lost during in vitro culture protective in vivoprotective in vivo

24 24 Endospores (spores) Dormant cellDormant cell Produced when starvedProduced when starved Resistant to adverse conditionsResistant to adverse conditions - high temperatures - organic solvents contain calcium dipicolinatecontain calcium dipicolinate Bacillus and ClostridiumBacillus and Clostridium


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