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Questions and Answers
What type of ribosomes do prokaryotic cells possess?
What type of ribosomes do prokaryotic cells possess?
Which of the following is a characteristic of prokaryotic cells?
Which of the following is a characteristic of prokaryotic cells?
How does the Gram stain help in bacterial classification?
How does the Gram stain help in bacterial classification?
What color do Gram-positive bacteria appear after a Gram stain?
What color do Gram-positive bacteria appear after a Gram stain?
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Which of the following statements about bacterial shape is correct?
Which of the following statements about bacterial shape is correct?
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What is the main function of the bacterial cell wall?
What is the main function of the bacterial cell wall?
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What factor can affect the classification of bacteria besides their shape?
What factor can affect the classification of bacteria besides their shape?
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What do prokaryotic cell membranes lack compared to eukaryotic membranes?
What do prokaryotic cell membranes lack compared to eukaryotic membranes?
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What describes the structure of a glycocalyx?
What describes the structure of a glycocalyx?
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Which of the following is a function of a bacterial capsule?
Which of the following is a function of a bacterial capsule?
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What process is crucial for the development of biofilms?
What process is crucial for the development of biofilms?
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Which bacteria are known to produce capsules?
Which bacteria are known to produce capsules?
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What type of immunity can degrade bacterial DNases and RNases?
What type of immunity can degrade bacterial DNases and RNases?
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Which statement about biofilms is false?
Which statement about biofilms is false?
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Which of the following enzyme types is involved in tissue injury from infections?
Which of the following enzyme types is involved in tissue injury from infections?
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What is a prominent feature of a capsule compared to a glycocalyx?
What is a prominent feature of a capsule compared to a glycocalyx?
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What is a primary characteristic of bacterial cells?
What is a primary characteristic of bacterial cells?
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Which of the following components of bacteria is important for immune regulation?
Which of the following components of bacteria is important for immune regulation?
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What is a characteristic of the viral life-cycle?
What is a characteristic of the viral life-cycle?
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How does the immune system primarily sense viruses?
How does the immune system primarily sense viruses?
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Which of the following characteristics is NOT associated with fungi?
Which of the following characteristics is NOT associated with fungi?
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What is one method by which anti-infective agents target pathogens?
What is one method by which anti-infective agents target pathogens?
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What is a key factor influencing the pathogenesis of infectious disease?
What is a key factor influencing the pathogenesis of infectious disease?
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Which of the following is NOT a target of vaccination strategies?
Which of the following is NOT a target of vaccination strategies?
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What provides protection for helminths against digestion and environmental stress?
What provides protection for helminths against digestion and environmental stress?
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Which class of helminths does not include flukes?
Which class of helminths does not include flukes?
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Which mode of transmission is not a common method for helminths?
Which mode of transmission is not a common method for helminths?
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What is a characteristic of the immune response to helminth infections?
What is a characteristic of the immune response to helminth infections?
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How long can helminth infections typically last?
How long can helminth infections typically last?
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What environmental factor is least likely to favor the transmission of helminths?
What environmental factor is least likely to favor the transmission of helminths?
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What is a common response of parasites to evade the host immune system?
What is a common response of parasites to evade the host immune system?
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What is a common characteristic of helminth infections in hosts?
What is a common characteristic of helminth infections in hosts?
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What type of RNA do all viruses utilize for protein translation?
What type of RNA do all viruses utilize for protein translation?
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Which of the following structures is a primary component of a virus?
Which of the following structures is a primary component of a virus?
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What is the function of the tegument or matrix proteins in a virus?
What is the function of the tegument or matrix proteins in a virus?
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What do viruses rely on host cells for?
What do viruses rely on host cells for?
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Which part of the virus is responsible for binding to host cells?
Which part of the virus is responsible for binding to host cells?
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Which type of nucleic acid can a virus contain?
Which type of nucleic acid can a virus contain?
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What is the primary function of viral glycoproteins found in the envelope?
What is the primary function of viral glycoproteins found in the envelope?
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What is a characteristic of viruses in terms of visibility?
What is a characteristic of viruses in terms of visibility?
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Study Notes
Bacterial Characteristics
- Bacteria are classified based on their shape (cocci, bacilli, spiral), cell wall type (Gram-positive, -negative, or neither), growth properties (aerobic/anaerobic), and antibiotic sensitivity.
- Bacterial cell walls are crucial for structure, protection from osmotic pressure, and are targeted by antibiotics.
- The Gram stain differentiates bacteria based on their cell wall composition. Gram-positive bacteria retain the primary stain (purple), while Gram-negative bacteria are destained and stained with a counter-stain (pink).
- Some bacteria have structures beyond their cell wall like glycocalyx (loosely adherent, non-uniform), capsules (well-defined, condensed layer), which can influence pathogenesis and immunity.
- Biofilms are communities of bacteria living together within a matrix of glycocalyx. They are resistant to antibiotics, disinfectants, and host immune responses.
- Capsules are visualized with negative stains and contribute to protection against phagocytosis.
- Bacteria can release enzymes like DNases, RNases, collagenases, proteases and hyaluronidases that damage host tissues.
Viral Characteristics
- Viruses are obligate intracellular parasites. They require host cells for their metabolism, protein synthesis, and replication.
- Viral structure includes a core (DNA/RNA), a capsid (protein shell), tegument or matrix proteins, and an envelope (lipid bilayer derived from infected cells containing viral glycoproteins).
- Viruses replicate through a cycle of binding, entry, replication, assembly, and release.
Fungal Characteristics
- Fungi are eukaryotic organisms that can cause infections.
- Common characteristics of fungi include: presence of a cell wall, filamentous growth (hyphae), and the ability to produce spores.
- Fungi can cause a variety of infections, from superficial skin infections to systemic diseases.
Parasitic Characteristics
- Parasites are organisms that live in or on another organism (the host) and benefit at the host's expense.
- Helminths are multicellular parasites like roundworms, tapeworms, and flukes, that can vary in size from 1 cm to 10 m.
- Helminth transmission occurs through ingestion of eggs or larvae, skin penetration by larvae, or inoculation from insect bites.
- Helminth infections are often chronic and present with eosinophilia (increased eosinophils in blood) due to a Th2 immune response.
- Parasites like helminths can evade the immune system through antigenic variation of surface proteins, camouflage, antibody/complement cleavage, and immune suppression.
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Description
Test your knowledge on the diverse characteristics of bacteria. This quiz covers classification based on shape, cell wall type, and growth properties. Additionally, you'll learn about Gram staining, biofilms, and the role of capsules in bacterial immunity.
