External Structure of Bacteria

External Structure of Bacteria

1. Glycocalyx

2. Substances that surround cells.

   • Composition
     • Polysaccharide
     • Polypeptide
       • Both
   • Organized
     • Capsule
       • Contribute to bacterial virulence
       • Protect from phagocytosis
   • Unorganized
     • Slime layer
   • Extracellular polymeric substance
     • Biofilms
       • Attach to target environment
     • Cell survival

3. Flagella

   • Long filamentous appendages that propel bacteria.
     • Lack of flagella
       • Astrichous
     • Peritrichous
     • Polar
       • Monotrichous
       • Lophotrichous
       • Amphitrichous
     • Parts
       • Out: Filament
         • Flagellin
       • Medium: Hook
         • Protein
       • In: basal body
         • Rod inserted into rings.
           • Gram-negative: 4 rings
             • 2 in & 2 out
             • 2 out
           • Gram-positive: 2 rings
             • 2 in
     • Motility
       • Taxis
         • Away environment
           • Repellent
         • Toward environment
           • Attractant
     • Protein H antigen

4. Axial Filaments

   • Spirochetes
     • Treponema palladium
       • Syphilis agent
     • Borrelia burgdorferi
       • Lyme disease agent
     • Movement
       • Axial filaments
       • Endoflagella
       • Corkscrew motion
         • Enable movement
           • Through body fluids.

5. Fimbriae and Pili

   • Uses
     • Attachment
     • DNA transfer
     • Composition
       • Pilin protein
       • 2 types
         • Frimbiae
           • Occurs at
             • Poles
             • Entire surface
           • Adhere surfaces
             • Create Biofilms
             • Other adherations
             • Epithelial surfaces
           • 100 per cell
         • Pili
           • 1-2 per cell
           • Uses
             • Motility
               • Twitching
                 • 1. Pilus extention
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                 • 2. Surface contact
                 • 3. Retraction
                   • Grappling hook model
                     • Intermittent movements
               • Gliding
                 • Myxobacteria
                 • Pilus retraction
                 • Low water travel
                   • Biofilms
                   • Soil
             • DNA transfer
               • Conjugation

6. Cell Wall

   • Semirigid
   • Uses
     • Stucture
     • Protection
       • Change of environment
     • Prevention
       • Bacteria rupturing
     • Anchorage for flagella
     • Antibiotics site of action
   • Contributes
     • Cause disease
   • Chemical Composition
     • Differentiate bacteria
     • Peptidoglycan
       • Repeating disaccharide
         • Monosaccharides
           • N-acetylglucosamine
             • Carbohydrate
           • N-acetylmuramic acid
       • Polypeptides
         • Lattice & protection
         • Tetrapeptide side chains
           • Linked by..
             • Bonds
             • Peptide cross-bridge
               • Short-chain amino acids
           • Constist of..
             • 4 amino acids
             • Backbone NAMs
   • Penicilin
     • Interferes linking
       • Lysis
         • Plasma rupture
         • Cytoplasm loss

7. Gram-Positive Cell Wall

   • Thick & rigid structure
   • Contain
     • Layers of peptidoglycan
     • Teichoic acids
       • Consist of..
         • Alcohol
         • Phosphate
       • 2 classes
         • Lipoteichoic acid
           • Spans peptidoglycan
           • Linked to plasma membrane
         • Wall teichoic acid
           • Linked to peptidoglycan layer
       • Bind & regulate
         • Cations movement
           • In
           • Out
         • Cell growth
       • Used for..
         • Prevention
           • Wall breakdown
           • Lysis
         • Provide
           • Antigenic specificity
             • To identify
               • Gram-positive bacteria

8. Gram-Negative Cell Walls

   • Consist of..
     • 1 Thin layer
       • Peptidoglycan
         • Bonded to..
           • Lipoproteins
             • Periplasm
               • Between
                 • Outer membrane
                 • Plasma membrane
               • Contains
                 • Degradative enzymes
                 • Transport proteins
     • Outer membrane
       • Consists of..
         • Lipopolysaccharides
           • Contains...
             • Lipids
             • Carbohydrates
           • Consists of..
             • Lipid A
               • LPS lipid portion
               • Embedded on top layer
               • Used as endotoxin
                 • When..
                   • Gram-negative bacteria die
               • Responsible for
                 • Gram-negative bacteria Infection symptoms
                   • Fever
                   • Dilation of blood vessels
                   • Shock
                   • Blood clotting
             • Core polysaccharide
               • Attached to..
                 • Lipid A
               • Contains
                 • Unusual sugars
               • Role
                 • Structural
                 • Provide stability
             • O polysaccharide
               • Composed of..
                 • Sugar molecules
               • Functions
                 • Antigen
                 • Distinguish gram-negative bacteria species
         • Lipoproteins
         • Phospholipids
       • Functions
         • Strong negative charge
           • Evading phagocytosis
           • Actions of complement
             • Defense of the host
         • Barrier
           • Some antibiotics
         • Digestive enzymes
           • Lysozyme
           • Detergents
           • Heavy metals
           • Bile salts
           • Certain dyes
         • Permeability
           • Due to..
             • Porins Proteins
               • Allow passage of..
                 • Molecules
                   • Nucleotides
                   • Disaccharides
                   • Peptides
                   • Amino acids
                   • Vitamin B12
                   • Iron

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