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Prokaryotic Anatomy I: Capsule, Flagella, Fimbriae, and Fili Nestor T. Hilvano, M.D., M.P.H. Learning Objectives You should be able to: 1. Describe the four major processes of living cells. 2. Classify prokaryotes as to shape and arrangement. 3. Compare and contrast prokaryotic and eukaryotic cells. 4. Describe the composition, function, and relevance to human health of glycocalyces. 5. Distinguish between capsules and slime layers. 6. Discuss the structure and function of prokaryotic flagella. 7. List and describe four prokaryotic flagellar arrangements. 8. Compare and contrast the structures and functions of fimbriae and pili. Prokaryotes • 3 basic bacterial morphology: a.) cocci, b.) bacilli, and c.) spirals • Spirals can be stiff (spirillum) or flexible (spirochetes) • Exercises: Give the shape/morphology of organisms: __ helical; __rod-like; __oval or round a. bacillus b. coccus c. spiral • Archaea = similar to bacteria, except it lack peptidogylcan cell walls and survive in extreme environment; no known disease in human; importance in industrial application ( thermophiles and their enzymes are used as additives in laundry detergents), and methanogens (methane traps heat, can lead to global warming; useful in sewage treatment) Major Processes of Living Cells • • • • Growth Reproduction Responsiveness Metabolism - * Viruses –inert agent; have no cellular structure (nonliving protein, nucleic acid) Compare Eukaryotes & Prokaryotes • ___ What cells lack nucleus and membrane – bound organelles, and are small (1 um or less in diameter) External Structures: Glycocalyces • Gelatinous, sticky substance • Importance= ability to survive/protection and to cause disease • Types of glycocalyx: a. Capsule- thick, firmly attached to cell surface for protection; ex: streptococcus pneumoniae b. slime layer- thin (loose), water soluble for protection from drying; ex: oral bacteria/biofilm cause tooth decay External Structures: Flagella • Long, whiplike structure protruding from a cell • Cell’s motility • Parts: - Filament, Hook, and Basal Body(rod and protein rings) • Rotate 360° • Serovars- species strains * Gram + =single pair of rings * Gram - = 2 pairs of rings Flagellar Arrangement Exercises: • • • • • ___ - no fagella ___ - Flagella all over ___ - 2 flagella one each end ___ - Tuft of polar flagella ___ - Single polar flagellum a. Monotrichous c. Amphitrichous e. Atrichous b. lophotrichous d. peritrichous * Endoflagella form axial filaments, corkscrew thru it’s medium (ex: spirochetes agent of syphilis) Flagellar Function • Rotate either clockwise or counterclockwise - Runs (straight; counterclockwise rotation) - Tumbles (random change in direction; clockwise rotation) • Taxis – movement towards a stimulus (phototaxis or chemotaxis) • Increase runs closer to concentration; increase tumbles farther away from concentration External Structures: Fimbriae • Short, sticky, proteinaceous, non-motile extensions • To adhere to one another, host, environment (Neisseria gonorrhoeae attached to mucous membrane of reproductive by fimbriae) • Important function in biofilms External Structures: Pili • For attachment; longer than fimbriae, shorter than flagella • Hollow, non-motile tubules of protein • Conjugation pili (F pili or sex pili) – mediate transfer of DNA/other substrate • Attachment pili (adheres to surfaces)- join bacterial cells Homework 1. 2. 3. 4. 5. 6. Definition of terms: spirillus, spirochetes, taxis, capsule, flagellum, prokaryote, fimbriae, slime layer, glycocalyx, pili, and biofilms. Differentiate prokaryotic from eukaryotic cells as to relative size, nucleus, and membranous organelles. Classify the shape of microbes: a) helical; b) rod-like; c) oval Give the importance of archaea. How do flagella of gram negative bacteria differ from gram positive bacteria? Describe flagellar arrangement.