vsv1
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The document summarizes key aspects of bacterial cell structure and function. It describes prokaryotic cells as lacking internal compartments and having circular chromosomes and 70S ribosomes. It distinguishes between gram-positive and gram-negative bacteria based on differences in their cell envelopes, which provide protection and regulate permeability. Structures such as flagella, pili, capsules, and endospores are described along with their functions in motility, adhesion, protection and dormancy.
vsv1
- 1. Dr. Alvin Fox The Bacterial Cell
- 2. Key Words Prokaryotic Outer membrane Eubacteria (Bacteria) Periplasmic space Oxidative phosphorylation Eukaryotic Spheroplast/protoplast Plasmid Flagella Chromosome Chemotaxis Ribosome Axial filament Peptidoglycan (murein, mucopeptide) Periplasmic binding protein Gram stain Permeases Gram negative Storage Granules Gram positive Pili (fimbriae) Cell envelope Capsule (slime layer, glycocalyx) Cell membrane Endospore (spore) Cell wall Archaebacteria ( Archaea )
- 3. PROKARYOTES BACTERIA ARCHAEA EUKARYOTES
- 4. Prokaryotes (Bacteria) Eubacter "True" bacteria human pathogens clinical or environmental one kingdom Archaea Environmental organisms second kingdom
- 5. Eukaryotes Other cell-based life e.g. plants animals fungi
- 6. Prokaryotic Cell (versus Eukaryotic Cell) Not compartmentalized Cell membranes lack sterols (e.g. cholesterol) Single circular chromosome Ribosomal are 70S - subunits 30S (16S rRNA) 50S (5S & 23S rRNA)
- 7. Bacteria versus Archaebacteria Eubacteria peptidoglycan (murein) muramic acid Archaebacteria pseudomurein no muramic acid
- 8. Bacteria versus Archaebacteria 16S rRNA sequence very different
- 9. Eukaryotic cell Prokaryotic cell Gram + Gram - Cell wall Cell (inner) membrane Outer membrane Ribosomes Rough endoplasmic reticulum Mitochondria Granule (e.g . animal) Cell wall Nucleoid Nucleus Cell membrane Capsule Cytoplasm Flagellum Pili
- 10. Bacteria Plasmids Extra-chromosomal DNA multiple copy number coding pathogenesis and antibiotic resistance factors bacterial replication
- 11. The Cell Envelope Gram Stain Gram Positive Gram Negative
- 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. 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. Outer Membrane Gram negative bacteria major permeability barrier space between inner and outer membrane periplasmic space store degradative enzymes Gram positive bacteria no periplasmic space
- 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. GRAM POSITIVE CELL ENVELOPE Cytoplasm Lipoteichoic acid Peptidoglycan-teichoic acid Cytoplasmic membrane Degradative enzyme
- 17. FLAGELLA Some bacteria are motile Locomotory organelles- flagella Taste environment Respond to food/poison chemotaxis
- 18. Flagella embedded in cell membrane project as strand Flagellin (protein) subunits move cell by propeller like action
- 19. Axial filaments spirochetes similar function to flagella run lengthwise along cell snake-like movement
- 20. Making Wall-less forms Result from action of: enzymes lytic for cell wall antibiotics inhibiting peptidoglycan biosynthesis Usually non-viable Wall-less bacteria that don’t replicate: spheroplasts (with outer membrane) protoplasts (no outer membrane). Wall-less bacteria that replicate L forms
- 21. Naturally Wall-less Genus Mycloplasma
- 22. Pili (fimbriae) hair-like projections of the cell sexual conjugation adhesion to host epithelium
- 23. Capsules and slime layers outside cell envelope well defined: capsule not defined: slime layer or glycocalyx usually polysaccharide often lost during in vitro culture protective in vivo
- 24. Endospores (spores) Dormant cell Produced when starved Resistant to adverse conditions - high temperatures - organic solvents contain calcium dipicolinate Bacillus and Clostridium