Prokaryote Classification Quiz
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Questions and Answers

Which characteristic is true about all archaea?

  • They are obligate anaerobes. (correct)
  • They are pathogenic.
  • They are aerobic organisms.
  • They evolved in an oxygen-rich atmosphere.

    • Which of the following is true about gram-positive bacteria?

  • They are all obligate anaerobes.
  • They do not contain any pathogenic species.
  • They are the earliest evolving bacteria.
  • They include the phyla firmicutes and actinobacteria. (correct)

    • What distinguishes proteobacteria from non-proteobacteria?

  • Proteobacteria are exclusively anaerobic.
  • Proteobacteria are primarily pathogenic.
  • Proteobacteria encompass oxygenic photosynthesizers. (correct)
  • Proteobacteria are typically gram-positive.

    • What is a significant feature of bacteroides bacteria?

    <p>They are gram-negative and obligate anaerobes.</p> Signup and view all the answers

    Which of the following statements about cyanobacteria is correct?

    <p>They can perform oxygenic photosynthesis.</p> Signup and view all the answers

    Which bacterial group is known for having a high number of pathogenic species?

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

    What is a common trait of extremophiles?

    <p>They can live in extreme conditions.</p> Signup and view all the answers

    Which of the following best describes the classification of spirochetes?

    <p>They are classified as gram-negative and may be pathogenic.</p> Signup and view all the answers

    Which of the following bacteria is responsible for syphilis?

    <p>Treponema pallidum</p> Signup and view all the answers

    Which type of bacteria are Bacteroides classified as?

    <p>Obligate anaerobes</p> Signup and view all the answers

    What unique feature allows spirochetes to move through tissues?

    <p>Axial filaments (endoflagella)</p> Signup and view all the answers

    Which electron donor do purple sulfur bacteria use for photosynthesis?

    <p>H2S</p> Signup and view all the answers

    What is a characteristic of purple non-sulfur bacteria?

    <p>They use an organic hydrogen source instead of H2S or H2O.</p> Signup and view all the answers

    Which of the following diseases is NOT caused by spirochetes?

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

    What role do Bacteroides play in the human colon?

    <p>Fermenting indigestible sugars</p> Signup and view all the answers

    What common characteristic do all obligate anaerobes share?

    <p>They are inhibited or killed by oxygen.</p> Signup and view all the answers

    What type of bacteria are Staphylococcus and Streptococcus classified as?

    <p>Low GC content gram-positive bacteria</p> Signup and view all the answers

    Which of the following is an example of a pathogenic streptococcus?

    <p>S. pyogenes</p> Signup and view all the answers

    Which hemolytic activity is displayed by Staphylococcus aureus?

    <p>Beta hemolysis</p> Signup and view all the answers

    What type of toxin does S. aureus produce?

    <p>Four types of toxins</p> Signup and view all the answers

    What method is used to categorize species of Enterococcus, Streptococcus, and Staphylococcus?

    <p>Level of hemolysis on blood agar plates</p> Signup and view all the answers

    Which of the following describes Actinobacteria?

    <p>High GC content gram-positive bacteria</p> Signup and view all the answers

    What is a distinguishing feature of the cell wall in Actinobacteria?

    <p>Presence of mycolic acid</p> Signup and view all the answers

    Which enzyme produced by pathogenic streptococci can lyse red blood cells?

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

    What is the infective form of Chlamydia known as an elementary body primarily characterized by?

    <p>Its endospore-like nature.</p> Signup and view all the answers

    Which of the following correctly describes the prokaryotic domain composed of organisms that can tolerate extreme environments?

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

    What method do spirochetes primarily use for motility?

    <p>Axial filament</p> Signup and view all the answers

    What distinguishes Chlamydophila psittaci in its pathogenicity?

    <p>It is responsible for pneumonia.</p> Signup and view all the answers

    Which group of bacteria is recognized for their ability to fix nitrogen in the ecosystem?

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

    Which of the following lists groups of bacteria based on their photosynthetic capabilities?

    <p>Cyanobacteria, purple sulfur, green non-sulfur</p> Signup and view all the answers

    What is a key characteristic of the family Enterobacteriaceae?

    <p>They are facultative anaerobes.</p> Signup and view all the answers

    What is the primary electron donor used by green sulfur bacteria during their photosynthesis?

    <p>H2S</p> Signup and view all the answers

    Which of the following accurately describes cyanobacteria?

    <p>They produce oxygen during photosynthesis.</p> Signup and view all the answers

    In terms of bacterial classification, what defines proteobacteria?

    <p>They are the largest group of bacteria.</p> Signup and view all the answers

    What type of disease does Corynebacterium diphtheriae cause?

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

    Which organism is known for producing most antibiotics?

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

    Which characteristic is associated with Mycobacterium tuberculosis?

    <p>Intracellular pathogen with mycolic acid cell wall</p> Signup and view all the answers

    What kind of environment do extreme halophiles require?

    <p>Salt concentration &gt; 25%</p> Signup and view all the answers

    Which of the following statements about Mycobacterium leprae is correct?

    <p>It infects peripheral nerves</p> Signup and view all the answers

    Which type of bacteria are classified as anaerobic extremophiles?

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

    What type of cell wall do archaea have?

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

    What distinguishes Streptomyces from other actinobacteria?

    <p>It produces most antibiotics</p> Signup and view all the answers

    Study Notes

    Prokaryote Classification

    • Bacteria and Archaea are the two domains of prokaryotes.
    • Bacteria were the first living organisms.
    • Archaea evolved in a pre-oxygen atmosphere.
    • Gram-negative bacteria evolved first, then gram-positive bacteria.
    • All archaea are extremophiles and obligate anaerobes.
    • Bacteria can be aerobic or anaerobic.
    • Bacteria have a wider range of environmental niches.
    • Archaea, unlike bacteria, are non-pathogenic.

    Bacterial Shapes and Arrangements

    • Major Bacterial Groups:
      • Bacteroides: Gram-negative rods, obligate anaerobes.
      • Photosynthetic Bacteria:
        • Anoxygenic: Sulfur/non-sulfur (purple/green), use an electron donor that is not water.
        • Cyanobacteria: Oxygenic, use water as an electron donor and produce oxygen.
      • Spirochetes: Coiled, move via axial filaments (endoflagella), many are pathogenic.
      • Chlamydias: Intracellular parasitic bacteria.
      • Gram-Positive Bacteria: Latest evolving bacteria, divided into the Firmicutes and Actinobacteria phyla.

    Non-Proteobacteria

    • Bacteroides:

      • Bacteroides fragilis: Gram-negative rod, obligate anaerobe, normal colon microbiota.
      • First bacteria to evolve.
      • Major inhabitants of the human colon.
      • Ferment indigestible sugar derivatives.
      • Break down toxins.
      • Produce communication molecules (polysaccharide A) that direct the innate immune response.

    • Photosynthetic Bacteria:

      • Anoxygenic: Carry out photosynthesis using a non-water electron donor.
      • Purple Sulfur Bacteria:
        • Use H2S as the electron donor.
        • Produce sulfides instead of oxygen.
        • Absorb higher energy wavelengths than green sulfur bacteria.
      • Purple Non-Sulfur Bacteria:
        • Use organic hydrogen sources as the electron donor.
        • Absorb higher energy wavelengths than green non-sulfur bacteria.
      • Green Sulfur Bacteria:
        • Use H2S as the electron donor for photosynthesis.
        • Produce sulfides instead of oxygen.
        • Aerotolerant anaerobes.
        • Absorb light at lower wavelengths than purple sulfur bacteria.
      • Green Non-Sulfur Bacteria:
        • Use organic hydrogen sources as the electron donor.
        • Aerotolerant anaerobes.
        • Absorb lower wavelengths than purple non-sulfur bacteria.

    • Spirochetes:

      • Spiral-shaped bacteria.
      • Coiled and move via axial filaments.
      • Many are pathogenic:
        • Treponema pallidum: Causes syphilis.
        • Treponema pertenue: Causes yaws.
        • Treponema pallidum subspecies endemicum: Causes bejel.
      • Can literally "drill" through skin and tissues.

    • Chlamydia:

      • Obligate intracellular parasites.
      • Diminished or no cell wall.
      • Grow intracellularly.
      • Elementary Bodies: The "endospore-like" infective form.
      • Reticulate Bodies: The intracellular replicative, cellular form.
      • Chlamydia trachomatis: Causes pelvic inflammatory disease and urethritis.
      • Chlamydophila psittaci: Causes respiratory psittacosis (pneumonia).

    Proteobacteria

    • All gram-negative bacteria.
    • Oxygen-tolerant.
    • Most are obligate aerobes or facultative anaerobes.
    • Great diversity (over 30% of known bacteria).
    • The largest bacterial phyla.
    • Diverse metabolisms, including heterotrophs, lithotrophs, and photosynthesizers.
    • Five classes: alpha, beta, gamma, delta, epsilon.
    • Include oxygenic and anoxygenic photosynthetic bacteria:
      • Cyanobacteria: Oxygenic, use water as the electron donor and produce oxygen.
      • Green Sulfur/Non-Sulfur Bacteria: Anoxygenic, use a non-water electron donor.
    • Many pathogenic species (Shigella, Salmonella).
    • Contain nitrogen-fixing species.

    Cyanobacteria

    • Also known as "blue-green algae."
    • Oxygenic photosynthetic bacteria.
    • Use water as the electron donor and produce oxygen.
    • Fix the majority of carbon dioxide in the ecosystem.
    • Many contain heterocysts that fix nitrogen.
    • Many contain gas vesicles that provide buoyancy.
    • Can be unicellular or filamentous, and colonial.

    Enterobacteriaceae

    • A family of enteric (gut) gram-negative rods.
    • All are facultative anaerobes and motile.
    • E. coli, an example, uses actin-like filaments to propel itself through host cytoplasm and invade neighboring cells.

    Gram-Positive Bacteria: Firmicutes

    • Low "GC content" gram-positive bacteria.

    • Streptococcus:

      • Coccus in chains.
      • Produce enzymes that destroy tissues.
      • Pathogenic streptococci include:
        • Streptococcus pneumoniae: Causes pneumonia.
        • Streptococcus mutans: Causes dental caries.
      • Beta-hemolytic streptococci hemolyze blood.
        • Streptococcus pyogenes: Causes strep throat and scarlet fever.

    • Staphylococcus:

      • Grape-like clusters.
      • Often antibiotic-resistant.
      • Staphylococcus aureus: Causes wound and skin infections, produces four types of toxins:
        • Hemolysin: Lyses red blood cells.
        • Leukotoxin: Lyses white blood cells.
        • Enterotoxin: Intestinal toxin.
        • Toxic-shock syndrome toxin-1: Can cause sepsis.
      • Species of Enterococcus, Streptococcus, and Staphylococcus are distinguished by their level of hemolysis on blood agar plates.

    Gram-Positive Bacteria: Actinobacteria

    • High "GC content" gram-positive bacteria.

    • A broad group, including antibiotic producers, decomposers, and pathogens.

    • Cell wall includes unusual cell wall lipids, such as mycolic acid.

    • Most stain with acid-fast stain.

    • Corynebacterium:

      • Corynebacterium diphtheriae: Causes diphtheria, characterized by difficulty breathing, heart failure, and paralysis.

    • Propionibacterium:

      • Produces propionic acid.
      • Propionibacterium acnes: Causes acne.

    • Gardnerella:

      • Gardnerella vaginalis: Causes vaginitis.

    • Streptomyces:

      • The largest genus of Actinobacteria.
      • Most produce endospores.
      • Isolated from soil.
      • Produce the majority of antibiotics.

    • Mycobacterium:

      • Acid-fast bacteria.
      • Mycobacterium tuberculosis:
        • Mycolic acid cell wall: Makes it an intracellular pathogen.
        • Highly infective obligate aerobe: Infects the lungs.
        • Highly contagious: Spread through aerosol transmission.
        • Many infections are antibiotic resistant.
      • Mycobacterium leprae:
        • Mycolic acid cell wall: Makes it an intracellular pathogen.
        • Causes leprosy: Infects peripheral nerves.
        • Targets skin, eyes, nose, and mouth.
        • Not highly contagious: Spread through direct contact.

    Archaea

    • Often referred to as "extreme bacteria," all are anaerobic extremophiles.
    • Unique cell wall: Pseudomurein, which lacks peptidoglycan.
    • Heterotrophic: Require organic and inorganic carbon for metabolism.
    • Non-pathogenic: No species has been shown to cause human disease.
    • Environmental niche: Extreme environments, including the human gut.
    • Extremophiles:
      • Extreme Halophiles: Require a salt concentration of over 25%.
      • Thermophiles: Require a growth temperature over 80°C.
      • Psychrophiles: Require low temperatures.

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    Ch.11 Prokaryotes PDF

    Description

    Test your knowledge about the two domains of prokaryotes: Bacteria and Archaea. Explore the evolution, characteristics, and classification of various bacterial groups and their distinctive features. This quiz covers topics such as bacterial shapes, arrangements, and metabolic types.

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