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Understanding Prokaryotic Cell Structure and Function: A Comprehensive Guide

This guide explores the intricate details of prokaryotic cell structure and function, delving into topics like cell wall appendages, reproduction, and antimicrobial actions. Learn about the different types of prokaryotes, such as bacteria and archaea, their unique characteristics, and how they reproduce asexually. Discover the significance of glycocalyx, flagella, and other cell components in their survival and pathogenicity. By covering essential concepts and providing visual examples, this guide serves as a valuable resource for understanding the world of prokaryotes.

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Understanding Prokaryotic Cell Structure and Function: A Comprehensive Guide

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  1. Prokaryotes Cell Structure and Function

  2. Taxonomy • Domains • Archaea • Bacteria • Eukarya • Kingdoms • P-C-O-F • Genus • Species

  3. Cells • Define • Processes • Metabolism • Nutrient source • Chemical processes • Growth • Responsiveness • Reproduction • Asexual • Sexual

  4. Size Comparison

  5. Eukaryotes Prokaryotes DNA Nucleus Other Organelles Cell wall Plasma Membrane Other characteristics Size Shape Location Comparison

  6. Eukaryotic Cell Structure

  7. Eukaryotic Plasma Membrane

  8. Bacterial Groups • Gram Positive • G + C • High • Corynebacterium • Mycobacterium • Actinomyces • Low • Clostridium • Bacillus • Listeria • Streptococcus • Staphylococcus • Mycoplasmas Coryne

  9. Bacterial Groups • Gram (-) • Proteobacteria • Alpha (O2) • Beta (N) • Gamma • Delta (S) • Epsilon (GI tract) • Chlamydia • Spirochetes • Treponema • Borrelia • Bacteroides H. pylori

  10. Prokaryotic Cell • Size • Shape • Monomorphic • Coccus • Bacillus • Spiral • Pleomorphic • Arrangement • Single • Diplo • Chains • Multiple planes

  11. Prokaryotic Reproduction • Asexual • Binary Fission • Daughter cells • Separate • Hinged (snap) • Spores • Filament end • Clone • Budding • outgrowth

  12. Binary Fission

  13. Cocci Arrangements • Appearance • Pairs • Chains • Four (Square-tetrad) • Cube (8): Sarcina • Cluster • Planes • 1 • 2 • 3 • Multiple Micrococcus

  14. Bacillus Arrangements • Appearance • Single • Diplobacillus • Streptobacillus • Coccobacillus • Palisade (“V” link) • Division • One plane

  15. Spiral Arrangement • Vibrio • Slight curved • Vibrio cholera • Spirillum • Stiff • Campylobacter • Helicobacter • Spirochete • Flexible • Treponema (Syphilis) • Borrelia (Lyme Ds)

  16. Prokaryotic Structure & Function Topics • Cell Wall Appendages • Cell Wall • Plasma Membrane • Cytoplasm • DNA region • Organelles • Reproduction • Antimicrobial actions

  17. Cell Wall Appendages • Glycocalyx (+/-) • Capsule • Slime Layer • S-layer • Surface proteins • Flagella • Fimbria • Pili

  18. Glycocalyx • Secreted by some bacteria • Produced inside • Extruded to outside • Aid in survivability • Aid in pathogenicity • Negatively charged • Composition • Polysaccharides (EPS) • Polypeptides • or Both

  19. Glycocalyx: Capsule • Organized repeating units • Thick • Firmly Attached • Function • Protect from desiccation and other environmental hazards • Evade host defenses via phagocytosis • Antigen: K

  20. Glycocalyx: Slime Layer • Unorganized • Thin • Loosely attached • Viscous • Water soluble • Function • Adherence • Protection • Trap nutrients • Form Biofilms

  21. S – Layer (Surface Layer) • Glycoprotein • Viscous • Thin • Organized in crystal lattice • Anchored to plasma membrane • Pores • Some G + and G – • Eubacteria • Archeae • Function • Strengthen and reinforce phospholipid bilayer • Adherence • Colonize • Resist flushing • Protection • Environment • Immune

  22. Biofims • Microbial community attached to surface • Resistance to • AB • Immune • Types • Environmental • Infectious • Dental Plaque • Endocarditis • Kidney Stones • CF

  23. Flagella • Appearance • 10 -20 micrometers • thin • Arrangement • Parts • Function

  24. Flagellar Arrangement • Monotrichous • Amphitrichous • Lophotrichous • Tuft • One or both poles • Peritrichous • Variations • Axial Filaments • Atrichous

  25. Flagella Examples • Monotrichous: • Pseudomonas aeruginosa • Amphitrichous: • Spirullum volutans • Lophotrichous: • E. coli • Peritrichous: • Proteus vulgaris

  26. Flagella Bacterial Swarm

  27. Endoflagellar Arrangement • Amphitrichous • Spiral around outer membrane sheath • Axial Filament rotation • Corkscrew motility • Spirochetes • Treponema (Syphilis) • Borrelia (Lyme’s disease)

  28. Flagella Anatomy: Exoflagella

  29. Gram Negative Flagellar Parts

  30. Flagellar Parts: Exoflagella • Filament • Flagellinchains in helix • Hollow core for repair • H protein antigen • E.coli O157:H7 • Hook • Protein coupling • L or curved shape • Function: rotation • Basal Body • Function: anchor • Central Protein Rod • Ringed protein structures • 4 rings for Gram Negative • 2 rings for Gram positive

  31. Flagellar Structure Mot proteins Fli proteins http://www.youtube.com/watch?v=Ey7Emmddf7Y

  32. Flagellar Stain • Special Stain • Determine • Presence • Number • Location • Stains used • Carbolfuscin • Pararosanaline • With mordants

  33. Flagellar Motility • Rotation • ATP pump • H+ • Na+ • Flagellar Motor • Stator: MotA, Mot B • Rotar: Fli proteins • Driven by proton Gradient [outside to inside cell] • -Taxis Movements • Stimulus: Photo- , Chemo- ; Negative vs. Positive • Clockwise = random movement [tumble] • Counterclockwise = forward movement [run]

  34. Motility Tests

  35. Flagella Summary • Function: Motility • Run vs Tumble • Phototaxis • Chemotaxis • Positive taxis • Negative taxis • Proteins allow for classification into groups called serovars: H antigen • Types • Endoflagella [spirochetes] • Exoflagella Arrangement • Monotrichous • Amphitrichous • Lophotrichous • Peritrichous • Anatomy • Filament • Hook • Basal body

  36. Pili • Pilin protein • Thin hollow tubes • Number • Average 1-2 per cell • Some have up to 10-100 • Glycoprotein or glycolipid tip • Length varies • Shorter: adherence • Longer: conjugation

  37. Pili Structure

  38. Conjugation (Sex or F) Pili Transfer DNA

  39. Fimbria • Gram Negative bacteria • Shorter than flagella aka “Short pili” • AA Protein: Fimbrilin • Sticky • Function • Adherence • Resist flushing • Biofilms

  40. Biofilms http://vimeo.com/30571458 • Attachment to surface of host tissue or other microbes • Cell to cell attachment • Production of extracellular polysaccharides [eps] • “Planktonic” colonization

  41. Bacterial Envelope • External Structures • Glycocalyx or S-layer • Fimbria/Pili/Flagella • Cell Wall • Shape • Osmotic Pressure • Protection • Periplasmic space • Enzymes • Nutrient processing

  42. Cell Walls

  43. Cell Wall Comparison G- G +

  44. Peptidoglycan Structural Unit Alternating D-L forms of AA alanine lysine glutamic acid DAPA

  45. Bacterial Cell Wall Structure Monomer • Peptidoglycan • Complex polysaccharide • Alternating Amino*Sugars • Covalent Linkage • Transglycolation • Beta 1-4 Linkage • Structure • NAM (muramic acid) • NAG (glucosamine) • Crossbridge • Linkage: Transpeptidases • Structure • Tetrapeptide (4) • Between NAMs • Bonded together @ Glycine • Short chains • Penta (5) connecting AA chain to link tetrapeptides * *

  46. Peptidoglycan Linkage Amine Disaccharides Polypeptides murein http://www.youtube.com/watch?v=SicrDfLgqB0

  47. Peptidoglycan Synthesis

  48. Gram Positive Bacteria

  49. Lysine to D-Alanine

  50. Teichoic Acids G (+) bacteria Polyalcohols Sugar – Phosphate AA “R” side chain Types Peptidoglycan- (Wall) Lipo- Function Anchor or Adhere Negative charge  Metal cations attracted Antigenic Controls autolysins

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