Bacteria revision notes quiz
40 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which structure allows some bacteria to withstand mechanical stress?

  • Biofilms (correct)
  • Pili
  • Endospores
  • Flagella

    • What is the correct genus name for the bacterium S. salivarius?

  • Salivarius
  • Firmicutes
  • Streptococcaceae
  • Streptococcus (correct)

    • Which of the following is associated with localized aggressive periodontitis?

  • Porphyromonas gingivalis
  • Bacteroides fragilis
  • Streptococcus salivarius
  • Aggregatibacter actinomycemcomitans (correct)

    • Which kingdom do bacteria belong to?

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

    What is the family name of Streptococcus salivarius?

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

    Which statement about species naming is correct?

    <p>Species names are typically in italics and lowercase.</p> Signup and view all the answers

    What type of bacterium is Porphyromonas gingivalis?

    <p>Gram-negative anaerobic</p> Signup and view all the answers

    What is the major characteristic of the division Firmicutes?

    <p>Low DNA content</p> Signup and view all the answers

    Which of the following is a type of mechanical stress that bacteria can resist?

    <p>Pressure/agitation</p> Signup and view all the answers

    Which of the following terms describes the systematic classification of organisms?

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

    What characteristic allows Gram negative bacteria to appear pink under a microscope?

    <p>Thin peptidoglycan layer</p> Signup and view all the answers

    Which factor is required for the metabolic processes of most Gram negative bacteria?

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

    Which of the following correctly describes anaerobes?

    <p>Do not need oxygen and may be harmed by it</p> Signup and view all the answers

    What significant component is characteristic of the outer layer of Gram negative bacteria?

    <p>Lipopolysaccharide layer</p> Signup and view all the answers

    In which environment are aerobes most commonly found?

    <p>Near the surface where oxygen is highest</p> Signup and view all the answers

    What type of disease is associated with Porphyromonas gingivalis?

    <p>Periodontal disease</p> Signup and view all the answers

    What type of organism requires a low oxygen environment to grow optimally?

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

    Which characteristic allows some bacteria to survive in dry conditions?

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

    What happens to Gram negative bacteria when exposed to crystal violet stain?

    <p>They do not retain the crystal violet stain</p> Signup and view all the answers

    Which group of microorganisms prefers moderate temperatures around 30-40 degrees Celsius?

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

    Which of the following does NOT describe the environmental requirements for Gram negative bacteria?

    <p>Optimum growth in aerobic conditions</p> Signup and view all the answers

    What do capnophiles specifically require for optimal growth?

    <p>Increased carbon dioxide levels</p> Signup and view all the answers

    What structural characteristic distinguishes Gram-positive bacteria from Gram-negative bacteria?

    <p>Thick peptidoglycan cell wall</p> Signup and view all the answers

    What is a common misconception about the structure of Gram negative bacteria?

    <p>They have a thick peptidoglycan layer.</p> Signup and view all the answers

    Which microorganisms are known to thrive in high salt concentrations?

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

    Which of the following statements is true about bacteria?

    <p>They are prokaryotic microorganisms</p> Signup and view all the answers

    What is the optimal temperature for thermophiles?

    <p>60-70 degrees Celsius</p> Signup and view all the answers

    What group of microorganisms prefers acidic environments?

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

    What is the primary function of bacteria?

    <p>Metabolizing and reproducing</p> Signup and view all the answers

    Which of the following bacteria is an example of a Gram-positive organism?

    <p>Staphylococcus aureus</p> Signup and view all the answers

    Which type of light can promote bacterial growth but high-intensity visible light can kill bacteria?

    <p>Low power visible light</p> Signup and view all the answers

    How is the DNA of bacteria structured?

    <p>As circular DNA chromosomes</p> Signup and view all the answers

    Which organisms are optimal at extremely high temperatures, typically around 90-100 degrees Celsius?

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

    What kind of microorganisms can tolerate and live in neutral pH environments?

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

    Which staining method is primarily used for Gram-positive bacteria?

    <p>Crystal violet staining</p> Signup and view all the answers

    Which of the following is NOT a feature of bacteria?

    <p>Eukaryotic organization</p> Signup and view all the answers

    Which of the following classifications includes organisms that prefer high temperature environments?

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

    What typically differentiates a Gram-negative bacterium from a Gram-positive bacterium when stained?

    <p>It has thinner peptidoglycan layers.</p> Signup and view all the answers

    What is the main reason that Gram-positive bacteria retain the crystal violet stain during the Gram staining process?

    <p>Thick peptidoglycan wall</p> Signup and view all the answers

    Which of these functions are commonly associated with bacteria?

    <p>Reproduce and metabolize nutrients</p> Signup and view all the answers

    Study Notes

    Bacteria

    • Small, single-celled microorganisms.
    • Prokaryotic: lack membrane-bound organelles, have a single circular DNA chromosome.
    • Gram-positive bacteria: have a thick peptidoglycan layer in their cell wall, retain crystal violet stain (e.g., Streptococcus mutans).
    • Gram-negative bacteria: have a thin peptidoglycan layer with a thick lipopolysaccharide layer, don't retain crystal violet stain, appearing pink (e.g., Porphyromonas gingivalis).
    • Gram-negative bacteria often possess endotoxins, which can contribute to inflammation.

    Environmental Requirements for Bacteria

    • Moisture: Required for metabolic processes. Most thrive in moist environments, but some can survive in dry conditions by forming spores.
    • Oxygen:
      • Anaerobes: do not need oxygen, may even be harmed by it (e.g., Porphyromonas gingivalis).
      • Aerobes: require oxygen for survival.
      • Microaerophiles: grow optimally in lower oxygen environments but still require some.
      • Facultative anaerobes: can adapt and live within a range of different oxygen levels. (e.g., Streptococcus mutans).
    • Carbon Dioxide: Capnophiles need increased CO2 to grow, but most can grow with normal atmospheric CO2 levels.
    • Temperature:
      • Psychrophiles: cold, optimal temperature 5-15 °C.
      • Mesophiles: moderate, optimal temperature 30-40 °C.
      • Thermophiles: high, optimal temperature 60-70 °C.
      • Hyperthermophiles: extremely high, optimal temperature 90-100 °C.
    • pH:
      • Acidophiles: thrive in acidic environments.
      • Neutrophiles: thrive in neutral environments.
      • Alkaliphiles: thrive in alkaline environments.
    • Light: High intensity visible light can kill bacteria, while low power visible and near-infrared light can promote bacterial growth.
    • Osmotic effect: Halophiles grow and develop in high salt concentration areas.
    • Mechanical stress: Some bacteria can withstand pressure/agitation by forming biofilms or protective structures (spores/capsules).

    Classification of Bacteria

    • Taxonomy: Systematic classification of organisms into groups.
    • The scientific name comes from the last two ranks: Genus and species.
    • Genus name is capitalized, species name is not.
    • Scientific name is usually in italics.
    • Example: Streptococcus salivarius (Genus: Streptococcus, Species: salivarius).

    Bacteria in Dentistry

    • Periodontal disease:
      • Porphyromonas gingivalis: Gram-negative, anaerobic bacteria that contributes to inflammation and tissue destruction.
      • Aggregatibacter actinomycetemcomitans: Gram-negative, facultative anaerobe that can cause localized aggressive periodontitis.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Bacteria Revision PDF

    Description

    This quiz explores the fundamental features of bacteria, focusing on their classification as prokaryotic microorganisms. It covers differences between gram-positive and gram-negative bacteria, as well as their environmental requirements for growth. Test your knowledge on the characteristics and conditions necessary for bacterial survival!

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser