Bacterial Pathogenesis Quiz
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Questions and Answers

What is the definition of pathogenicity?

  • The actual damage or injury that impairs host function
  • The enhanced ability of microbes to attach to host tissues
  • The ability of a parasite to inflict damage on the host (correct)
  • The ability of a microorganism to establish in a host

    • How do pathogens typically adhere to epithelial cells?

  • By gaining access to host tissues through a portal of entry
  • Via receptors on the pathogen's surface that enable it to bind to host cells
  • Through interactions between molecules on the pathogen and host tissues (correct)
  • By forming biofilm and adhering to the host via the biofilm

    • What are adhesins on a pathogen's surface primarily composed of?

  • Carbohydrates
  • Nucleic acids
  • Peptidoglycan
  • Glycoprotein or lipoprotein (correct)

    • What is the critical factor in establishing an infection for pathogens?

    <p>Portal of entry</p> Signup and view all the answers

    What are host receptors that pathogens bind to primarily composed of?

    <p>Extracellular matrix, cell surface glycoproteins, membrane lipids</p> Signup and view all the answers

    Which of the following is a function of the complement system?

    <p>Boosting the efficiency of both innate and adaptive immune responses</p> Signup and view all the answers

    What is the role of toll-like receptors in phagocytes?

    <p>Recognizing and interacting with specific pathogen-associated molecular patterns</p> Signup and view all the answers

    What is a key transcription factor activated in many different pathways in phagocytes?

    <p>NFκB (nuclear factor kappa-light-chain-enhancer)</p> Signup and view all the answers

    What is the main role of leukocytes at the site of infection during inflammation?

    <p>Releasing proinflammatory cytokines to increase vascular permeability</p> Signup and view all the answers

    What can lead to septic shock in the body?

    <p>Systemic inflammation and increased vascular permeability</p> Signup and view all the answers

    What is the main function of Granzyme?

    <p>Induces apoptosis (programmed cell death)</p> Signup and view all the answers

    What is the role of Interferons in the immune response?

    <p>Serve as a warning system and prevent viral replication</p> Signup and view all the answers

    What is the function of T lymphocytes (T cells) in the immune response?

    <p>Defend against intracellular pathogens</p> Signup and view all the answers

    What is the characteristic of B lymphocytes in terms of specificity?

    <p>Display membrane-bound immunoglobulins on their surface with specificity to one antigen</p> Signup and view all the answers

    What is the main characteristic of adaptive immunity?

    <p>Directed toward specific molecular components of the microbes</p> Signup and view all the answers

    What is the function of bacterial capsules in pathogenicity?

    <p>They serve for adherence and protection</p> Signup and view all the answers

    What is the role of adherence structures such as fimbriae, pili, and flagella in bacterial infections?

    <p>Implicated in specific bacterial infections</p> Signup and view all the answers

    What is the process of colonization in the context of host-pathogen interactions?

    <p>The growth of microorganisms in host tissues, usually beginning in mucous membranes</p> Signup and view all the answers

    What is the significance of virulence attenuation in pathogen strains?

    <p>It is important for vaccine development</p> Signup and view all the answers

    When do opportunistic infections occur?

    <p>In compromised hosts, such as individuals with weakened immune systems or noninfectious diseases</p> Signup and view all the answers

    Which cells primarily drive innate immunity?

    <p>Phagocytes</p> Signup and view all the answers

    What is the process of differentiation of blood stem cells into different blood cells influenced by cytokines and chemokines called?

    <p>Hematopoiesis</p> Signup and view all the answers

    Which type of stem cells produce T cells, B cells, and natural killer cells?

    <p>Lymphoid stem cells</p> Signup and view all the answers

    What is the main function of lymph nodes?

    <p>Contain high concentrations of immune system cells</p> Signup and view all the answers

    What is the primary driving force behind competitive exclusion by harmless microbes?

    <p>Limiting available nutrients and sites for infection</p> Signup and view all the answers

    Which of the following is true about coagulase and streptokinase?

    <p>Coagulase and streptokinase are virulence factors that manipulate blood clotting, affecting the immune system's ability to combat infections.</p> Signup and view all the answers

    What is the mechanism of action of Diphtheria exotoxin?

    <p>Blocks protein synthesis by ADP-ribosylation of the elongation factor EF-2.</p> Signup and view all the answers

    What is the function of Botulinum toxin?

    <p>Inhibits muscle contraction by cleaving proteins involved in releasing acetylcholine.</p> Signup and view all the answers

    What is the role of endotoxins in bacterial pathogenesis?

    <p>Endotoxins are released when bacterial cells lyse and are generally less toxic than exotoxins.</p> Signup and view all the answers

    What is the difference between innate immunity and adaptive immunity?

    <p>Innate immunity is the nonspecific immunity of multicellular organisms that targets pathogens seeking to colonize the host, while adaptive immunity is the acquired ability to recognize and destroy specific pathogens or their products.</p> Signup and view all the answers

    What is the function of a virion in the context of viruses?

    <p>To facilitate transmission of the virus</p> Signup and view all the answers

    What is the primary role of capsid in a virus?

    <p>To surround the genome of the virus</p> Signup and view all the answers

    What is the characteristic of enveloped viruses?

    <p>They have an outer layer made of phospholipid bilayer and viral proteins</p> Signup and view all the answers

    What is the outcome of a lysogenic infection?

    <p>Host cell genetically altered because viral genome becomes part of host genome</p> Signup and view all the answers

    How can viruses be classified based on their genetic material?

    <p>DNA or RNA genomes, single or double-stranded</p> Signup and view all the answers

    What is the main function of virion surface proteins in a virus?

    <p>Host cell attachment and may include enzymes involved in infection/replication</p> Signup and view all the answers

    What is the primary driving force behind the maintenance of small microbial genomes?

    <p>Gene deletions</p> Signup and view all the answers

    What evolutionary mechanism plays a significant role in microbial evolution by allowing DNA transfer between distant evolutionary branches?

    <p>Conjugation</p> Signup and view all the answers

    Which genetic event is more frequent in microbial genome dynamics, contributing to the maintenance of small microbial genomes?

    <p>Gene deletions</p> Signup and view all the answers

    What is the result of a gain-of-function mutation in E. coli after 31,500 generations?

    <p>Ability to utilize citrate</p> Signup and view all the answers

    What role do gene families, including homologs, orthologs, and paralogs, play in genome evolution and diversification?

    <p>Crucial role</p> Signup and view all the answers

    What allows one gene copy to evolve new functions while the other maintains the original function?

    <p>Gene duplication</p> Signup and view all the answers

    What is the primary driving force behind competitive exclusion by harmless microbes?

    <p>Competition for nutrients and space</p> Signup and view all the answers

    What is the characteristic of B lymphocytes in terms of specificity?

    <p>They undergo clonal selection and expansion</p> Signup and view all the answers

    What is the role of endotoxins in bacterial pathogenesis?

    <p>Inducing fever and inflammation</p> Signup and view all the answers

    What is the main function of Granzyme?

    <p>Inducing apoptosis in infected cells</p> Signup and view all the answers

    What is the main role of leukocytes at the site of infection during inflammation?

    <p>Engulfing and destroying pathogens</p> Signup and view all the answers

    What are host receptors that pathogens bind to primarily composed of?

    <p>Protein and carbohydrate complexes</p> Signup and view all the answers

    What is a characteristic of the influenza A virus genome?

    <p>It is segmented</p> Signup and view all the answers

    What is the causative agent of COVID-19?

    <p>SARS-CoV-2</p> Signup and view all the answers

    What is a characteristic of lysogeny maintenance in phages?

    <p>It is maintained by phage-encoded repressor protein</p> Signup and view all the answers

    What is a feature of retrovirus integration into the host genome?

    <p>It involves dsDNA integration into the genome by integrase</p> Signup and view all the answers

    What is the primary source of genetic diversity in viruses?

    <p>Mutation</p> Signup and view all the answers

    What is the role of viroplasms in some eukaryotic cells during viral infection?

    <p>Formation of viroplasms</p> Signup and view all the answers

    What can be inferred from >97% SSU rRNA sequence identity?

    <p>The same species</p> Signup and view all the answers

    What is the primary purpose of stable isotope probing in microbial communities?

    <p>Identify microorganisms utilizing specific compounds</p> Signup and view all the answers

    What does metaproteomics measure in a microbial community?

    <p>Protein diversity and abundance</p> Signup and view all the answers

    What is the advantage of using multilocus sequence analysis over SSU ribosomal RNA genes for distinguishing species?

    <p>Can distinguish species that cannot be resolved by rRNA sequences</p> Signup and view all the answers

    What is the main role of stable isotopes and isotopic fractionation in microbial ecosystems?

    <p>Trace the biological or geological origin of ancient environments</p> Signup and view all the answers

    What is the significance of microbial diversity in ecosystems?

    <p>Expressed through species richness and abundance</p> Signup and view all the answers

    Study Notes

    Exotoxins and Innate Immunity in Bacterial Pathogenesis

    • About 2 million people in the United States are affected by various medical procedures such as surgery, biopsy, catheterization, and hypodermic injection, with a mortality rate of approximately 5%.
    • Pathogenic bacteria release enzymes that break down the host's tissues, such as hyaluronidase from Streptococcus pyogenes and collagenase from Clostridia causing gangrene.
    • Coagulase and streptokinase are virulence factors that manipulate blood clotting, affecting the immune system's ability to combat infections.
    • Exotoxins, including AB toxins, cytolytic toxins, and enterotoxins, cause disease by inhibiting host cell function or killing host cells.
    • Diphtheria exotoxin, produced by Corynebacterium diphtheriae, blocks protein synthesis by ADP-ribosylation of the elongation factor EF-2.
    • Botulinum toxin, produced by Clostridium botulinum, inhibits muscle contraction by cleaving proteins involved in releasing acetylcholine.
    • Tetanus toxin, produced by Clostridium tetanus, floods neuromuscular junctions with acetylcholine, causing muscle contraction.
    • Cholera enterotoxin, produced by Vibrio cholera, causes massive fluid secretion into the intestinal lumen by affecting cellular processes and ionic balance.
    • Cytolytic exotoxins degrade the cytoplasmic membrane, causing cell lysis and death, often through phospholipase activity or pore formation.
    • Endotoxins, part of the lipopolysaccharide component of Gram-negative bacterial outer membranes, are released when bacterial cells lyse and are generally less toxic than exotoxins.
    • Innate immunity is the nonspecific immunity of multicellular organisms that targets pathogens seeking to colonize the host and involves rapid responses by phagocytes.
    • Adaptive immunity is the acquired ability to recognize and destroy specific pathogens or their products, involving a response by lymphocytes and post-exposure immunity.

    Microbial Ecosystems and Diversity: Key Concepts and Analytical Approaches

    • Nucleotide sequence differences between homologous genes reflect accumulated mutations since a common ancestor, and can be used to infer relationships
    • SSU ribosomal RNA genes are highly conserved and easily sequenced for inferring relationships; >97% SSU rRNA sequence identity indicates the same species
    • Multilocus sequence analysis using protein-encoding genes can distinguish species that cannot be resolved by rRNA sequences
    • Whole genome analysis is increasingly common, allowing reconstruction of metabolic/physiological characteristics and estimation of relatedness using average nucleotide identity
    • Metaproteomics measures protein diversity and abundance in a microbial community, while metabolomics analyzes cellular and extracellular metabolites
    • Direct chemical measurements and microsensors are used to measure specific metabolites and activities in microbial habitats
    • Stable isotopes and isotopic fractionation can trace the biological or geological origin of ancient environments
    • Stable isotope probing involves feeding microorganisms with labeled substrates to identify those utilizing specific compounds in a microbial community
    • Microbes account for ~50% of all biomasses on Earth, residing in various habitats within ecosystems
    • Microbial diversity is expressed through species richness (total number of species) and abundance (proportion of each species) in an ecosystem
    • Guilds, consisting of metabolically related microbial populations, form communities that interact with macroorganisms and abiotic factors
    • Microbes play essential roles in biogeochemical cycles, including the transformations of key elements such as C, N, S, and Fe, through oxidation-reduction reactions

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    Related Documents

    Microbiological Infection & Pathogenesis Notes PDF
    BIOL 371 Class Notes - Microbiology (Concordia University) PDF

    Description

    Test your knowledge of exotoxins and innate immunity in bacterial pathogenesis with this quiz. Explore the effects of pathogenic bacteria's enzymes and virulence factors, as well as the mechanisms of action of various exotoxins such as diphtheria, botulinum, tetanus, and cholera toxins. Gain insights into the interplay between innate and adaptive immunity in combating bacterial infections.

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