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Questions and Answers
What is the primary component of the bacterial cell wall?
What is the primary component of the bacterial cell wall?
Which of the following bacteria has a microcapsule?
Which of the following bacteria has a microcapsule?
Which substance is NOT a component of the capsule?
Which substance is NOT a component of the capsule?
What is the function of the capsular antigen?
What is the function of the capsular antigen?
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What is the role of the bacterial cell wall in cell division?
What is the role of the bacterial cell wall in cell division?
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What environmental condition is NOT favorable for capsule development?
What environmental condition is NOT favorable for capsule development?
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Which of these is a function of the capsule?
Which of these is a function of the capsule?
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Which sugar derivatives make up peptidoglycan?
Which sugar derivatives make up peptidoglycan?
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How do capsulated bacteria contribute to their pathogenicity?
How do capsulated bacteria contribute to their pathogenicity?
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Which group of bacteria has a simpler cell wall structure?
Which group of bacteria has a simpler cell wall structure?
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Study Notes
Capsule
- Gelatinous secretion of bacteria, forming a thick coat around the cell wall
- Dependent on favorable environmental conditions, such as high sugar concentration, blood serum, or growth in a living host
- Can be composed of complex polysaccharide, polypeptide, or hyaluronic acid
- Examples: pneumococci, Klebsiella, Bacillus anthracis, and Streptococcus pyogenes
- Thinner capsules are called microcapsules, e.g. Meningococci, Streptococcus pyogenes, and Haemophilus influenzae
Functions of Capsule
- Protects against deleterious agents, such as lytic enzymes
- Contributes to virulence of pathogenic bacteria by inhibiting phagocytosis
- Capsular antigen is a hapten in nature, specific for bacteria
Cell Wall
- A rigid, chemically complex structure between the cell membrane and capsule/slime layer
- Main component is peptidoglycan, responsible for shape and strength
- Composed of a disaccharide with two sugar derivatives: N-acetylglucosamine and N-acetylmuramic acid
- Joined together by short peptide chains
Functions of Cell Wall
- Protects internal structure (supporting layer)
- Gives shape to the cell and provides rigidity
- Plays a role in bacterial division and offers resistance to environmental stress
- Protects bacteria from changes in osmotic pressure
Classification of Bacterial Cells
- Based on structural differences between Gram-positive and Gram-negative cell walls
- Gram-positive bacteria have simpler chemical structures compared to Gram-negative bacteria
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Description
Learn about the characteristics and composition of bacterial capsules, including their formation, environmental dependencies, and examples of bacteria with capsules.
