Structure External To The Cell Wall Flashcards
Q: What are some structures external to the prokaryotic cell wall?
A: Glycocalyx, flagella, axial filaments, fimbriae, and pili.
Q: What is the glycocalyx?
A: A sticky, gelatinous layer (often called “sugar coat”) surrounding the cell, composed of polysaccharides, polypeptides, or both.
Q: What is the general function of the glycocalyx?
A: To protect and sometimes aid in attachment to surfaces; it surrounds the cell wall
Q: How is the glycocalyx produced?
A: It is made inside the cell and then secreted to the cell surface.
Q: What does the composition of glycocalyx depend on?
A: The chemical composition varies widely with the species.
Q: What structures are typically found in prokaryotic cells?
A: Cytoplasm, ribosomes, a plasma membrane, a nucleoid, and almost always a cell wall.
Q: Do prokaryotic cells have membrane-enclosed organelles?
A: No, prokaryotic cells usually lack membrane-enclosed organelles.
Q: What role does the capsule play in bacteria?
A: It contributes to bacterial virulence (ability to cause disease).
Q: Which structures help in bacterial identification?
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A: The cell wall and flagella
Q: What bacterial structure is often a target of antimicrobial agents?
A: The cell wall.
Q: What are plasmids?
A: Small DNA molecules that carry genes, such as those for antibiotic resistance or toxin production.
Q: Can plasmids be exchanged between bacteria?
A: Yes, plasmids may be exchanged between bacteria.
Q: What is a glycocalyx called when it is well-organized and firmly attached to the cell wall?
A: A capsule.
Q: How can the presence of a capsule be determined?
A: By using negative staining.
Q: What is the glycocalyx called if it is unorganized and loosely attached to the cell wall?
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A: A slime layer
Q: How do capsules contribute to bacterial virulence?
A: Capsules protect pathogenic bacteria from being destroyed by phagocytosis, increasing their ability to cause disease.
Q: What is an example of a bacterium that produces a capsule for protection?
A: Bacillus anthracis, which produces a capsule of D-glutamic acid.
Q: What is an example of a bacterium that produces a capsule for protection?
A: Bacillus anthracis, which produces a capsule of D-glutamic acid.
Q: Why is Bacillus anthracis’s capsule significant for its ability to cause anthrax?
A: The capsule may prevent it from being destroyed by phagocytosis, allowing it to survive and cause disease.
Q: Why is Bacillus anthracis’s capsule significant for its ability to cause anthrax?
A: The capsule may prevent it from being destroyed by phagocytosis, allowing it to survive and cause disease.
Q: Under what condition can Streptococcus pneumoniae cause pneumonia?
A: Only when the cells are protected by a polysaccharide capsule.
Q: What happens to Streptococcus pneumoniae cells that lack a capsule?
A: They cannot cause pneumonia and are readily phagocytized by immune cells.
Q: What role does the polysaccharide capsule play in Klebsiella bacteria?
A: It prevents phagocytosis, allowing the bacterium to adhere to and colonize the respiratory tract.
