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How does the glycocalyx contribute to a bacterium's virulence?
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The glycocalyx, which can form either a capsule or a slime layer, helps bacteria evade the host immune system and increases virulence by enhancing attachment and survival.
What is the structural organization of DNA within prokaryotic cells?
Prokaryotic cells contain DNA within a nucleoid, which is not membrane-bound, and typically have a single circular chromosome.
What are mycoplasma bacteria, and how are they unique in terms of cell wall structure?
Mycoplasma bacteria lack a cell wall and have a high lipid content in their membranes, making them unique among bacteria.
What are the distinctive features of Gram-positive and Gram-negative bacteria?
Gram-positive bacteria have a thick peptidoglycan layer and stain purple, whereas Gram-negative bacteria have a thinner peptidoglycan layer and an outer lipopolysaccharide membrane, staining pink.
Why is it significant that antibiotics can target 70s ribosomes in bacteria but not 80s ribosomes in human cells?
This selective targeting allows antibiotics to disrupt bacterial protein synthesis without affecting human cells, which mitigates side effects and enhances treatment efficacy.
What is the role of mycolic acid in mycobacteria, and how does it affect staining methods?
Mycolic acid provides a waxy coat to mycobacteria, making them resistant to conventional staining techniques. This requires the use of acid-fast staining to visualize them effectively.
Describe the process of binary fission in prokaryotic cells.
Binary fission is an asexual reproduction method where a single prokaryotic cell divides into two identical daughter cells.
How do active and passive transport differ across bacterial plasma membranes?
Active transport requires ATP to move substances against their concentration gradient, while passive transport does not require energy and involves movement along the concentration gradient via diffusion, facilitated diffusion, or osmosis.
Describe the different bacterial shapes and provide an example of each.
Bacterial shapes include coccus (round), bacillus (rod-shaped), spirillum (spiral-shaped), and vibrio (comma-shaped). Examples: Cocci - Staphylococcus, Bacilli - Bacillus subtilis, Spirillum - Helicobacter pylori, Vibrio - Vibrio cholerae.
What is the role and composition of the bacterial cell wall, and how does it differ from plant and fungi cell walls?
The bacterial cell wall, composed of peptidoglycan, provides structural integrity and protection. Plant cell walls are primarily composed of cellulose, whereas fungi have cell walls made of chitin.
Explain the importance of flagella to bacterial motility and how they can be classified.
Flagella are crucial for bacterial motility, allowing movement towards favorable environments. They can be classified as peritrichous, monotrichous, lophotrichous, or amphitrichous based on their arrangement.
How are the ribosomes in prokaryotic and eukaryotic cells different?
Prokaryotic ribosomes are 70s in structure, while eukaryotic ribosomes are larger, with an 80s structure.
Explain the concept of tonicity and its impact on prokaryotic cells.
Tonicity refers to the relative concentration of solutes outside the cell compared to inside. Hypertonic solutions cause cells to shrink, hypotonic solutions cause cells to swell, potentially bursting, and isotonic solutions cause no net water movement.
What is the significance of endospores in bacterial survival?
Endospores allow bacteria to survive extreme environmental conditions by entering a dormant state, providing resistance to heat, desiccation, and chemical damage.
What differentiates fimbriae from a sex pilus in bacteria?
Fimbriae are short, numerous structures that aid in adhesion to surfaces, while a sex pilus is longer and fewer in number, facilitating the transfer of genetic material between bacterial cells.
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