Bacterial Anatomy 2.0

• What is the gelatinous layer covering bacteria called?

  Capsule/Glycocalyx/Slime layer
• What is the primary composition of the capsule in Bacillus anthracis?

  Polymerized D-glutamic acid
• How do capsules help bacteria form biofilms?

  They assist in adherence to surfaces
• What is one function of capsules in bacteria?

  Inhibits ingestion by phagocytes
• How do capsules protect bacteria from lysozyme?

  By providing a protective barrier
• What role do capsules play in biofilm growth?

  Prevent access of host cells or antibiotics
• How do capsules help prevent dehydration in bacteria?

  By retaining moisture around the cell
• What is the main component of the bacterial cell wall?

  Peptidoglycan (murein)
• How does the thickness of peptidoglycan distinguish bacteria?

  It differentiates gram positive from gram negative
• What two components overlap in peptidoglycan?

  1. acetyl glucosamine (NAG) & N-acetyl muramic acid (NAM)
• Which bacteria lack a peptidoglycan cell wall?

  Mycoplasma and ureaplasma
• What characterizes the cell wall of gram positive bacteria?

  Thick peptidoglycan layer (50-90%)
• What are teichoic acids responsible for in gram positive bacteria?

  Control of cell division and morphology
• What is the function of lipoteichoic acid in gram positive bacteria?

  Anchors cell wall to cell membrane
• How do polysaccharides and proteins protect the peptidoglycan layer?

  By shielding it from enzymatic action
• What is a key feature of the cell wall in gram negative bacteria?

  Thin peptidoglycan layer (5-10%)
• What additional structure do gram negative bacteria have?

  An outer membrane
• What is contained in the periplasmic space of gram negative bacteria?

  Digestive enzymes and transport proteins
• What is the role of porin proteins in gram negative bacteria?

  Transport solutes in and out of the cell
• What anchors the outer membrane to peptidoglycan in gram negative bacteria?

  Lipoprotein
• What is the function of lipopolysaccharide (LPS) in gram negative bacteria?

  Protects from proteolytic enzymes
• What is the major component of lipopolysaccharide (LPS)?

  Lipid A - endotoxin
• What is the significance of Lipid A in gram negative bacteria?

  Responsible for endotoxic activities
• What is unique about the cell envelopes of Mycobacteria?

  They contain Mycolic acid
• What is one function of the bacterial cell wall?

  Maintains cell shape
• How does the cell wall protect bacteria from osmotic lysis?

  By providing structural integrity
• What determines a bacterium's reactivity to Gram stain?

  The structure of its cell wall
• What is a site of action for certain antimicrobial agents?

  The bacterial cell wall
• How does the cell wall enhance pathogenicity?

  By providing protection and structure
• What separates the cell wall from the cytoplasm?

  Plasma/Cytoplasmic/Cell membrane
• What is the function of the plasma membrane?

  Acts as a semi-permeable membrane
• What is the composition of the plasma membrane?

  Lipoproteins with small carbohydrates
• What is a unique feature of the plasma membrane in Mycoplasma?

  It contains sterols
• What is one function of the plasma membrane?

  Active transport of molecules into the cell
• What does the plasma membrane synthesize?

  Precursor of the cell wall
• What does the plasma membrane secrete?

  Enzymes and toxins
• What are pili?

  Hair-like projections on the cell surface
• How do pili differ from flagella?

  Pili are shorter and straighter
• What is the function of sex pili?

  Involved in conjugation
• What are common pili used for?

  Attachment to surfaces