Bacterial Cell-Surface Structures
22 Questions
4 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

What is the primary function of a bacterial flagellum?

  • Transfer of genetic material
  • Attachment to surfaces
  • Locomotion of the cell (correct)
  • Protection from the immune system
  • What structure is involved in the attachment of bacterial cells to surfaces or other individuals in a colony?

  • Capsule
  • Pili
  • Fimbriae (correct)
  • Flagella
  • What characteristic best describes extreme thermophiles?

  • They thrive in highly saline environments.
  • They are strict anaerobes and are poisoned by O2.
  • They thrive in very hot environments. (correct)
  • They generate oxygen through photosynthesis.
  • Which category of prokaryotes obtains energy from light?

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

    Which type of bacteria includes helical heterotrophs?

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

    What type of nutritional mode combines energy from chemicals and carbon from CO2?

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

    Which structure is responsible for the transfer of genetic material between bacterial cells?

    <p>Sex pili</p> Signup and view all the answers

    Which type of bacteria decompose soil?

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

    What is the major difference between exotoxins and endotoxins in pathogenic bacteria?

    <p>Exotoxins can cause disease even if bacteria are not present.</p> Signup and view all the answers

    What do heterotrophs require as a carbon source?

    <p>Organic nutrient</p> Signup and view all the answers

    What adaptation allows some pathogenic bacteria to cause disease even if the bacteria are no longer present?

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

    Which bacteria is known to break down food undigested by human intestines?

    <p>Mutualistic bacteria</p> Signup and view all the answers

    Which type of prokaryote generates oxygen?

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

    What is a distinguishing feature of bacteriophages?

    <p>They have a complex capsid structure</p> Signup and view all the answers

    What determines whether a virus is categorized as a DNA virus or an RNA virus?

    <p>The kind of nucleic acid in its genome</p> Signup and view all the answers

    Which of the following structures is responsible for enclosing the viral genome?

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

    What are capsomeres?

    <p>Protein subunits of capsids</p> Signup and view all the answers

    What is a distinctive feature of methanogens?

    <p>They are strict anaerobes producing methane as waste.</p> Signup and view all the answers

    From where do viral envelopes originate?

    <p>Host cell membranes</p> Signup and view all the answers

    How do bacteriophages typically insert their DNA into a host?

    <p>By attaching and injecting via a protein tail piece</p> Signup and view all the answers

    What is the function of a viral envelope?

    <p>To help the virus infect hosts</p> Signup and view all the answers

    Which of the following molecules can be found in viral envelopes?

    <p>A combination of viral and host cell molecules</p> Signup and view all the answers

    Study Notes

    Cell-Surface Structures

    • Bacterial cell walls have various structures involved in locomotion, attachment, and genetic material transfer.
    • Flagella are responsible for locomotion of the cell.
    • Fimbriae are involved in attachment to suitable surfaces or other individuals in a colony.
    • Sex pili are responsible for transferring genetic material.

    Prokaryote Nutritional and Metabolic Adaptations

    • Prokaryotes can be categorized by how they obtain energy and carbon.
    • Phototrophs obtain energy from light.
    • Chemotrophs obtain energy from chemicals.
    • Autotrophs require CO2 as a carbon source.
    • Heterotrophs require an organic nutrient as a carbon source.
    • Four major modes of nutrition are:
      • Photoautotrophy
      • Chemoautotrophy
      • Photoheterotrophy
      • Chemoheterotrophy

    Archaea

    • Archaea share certain traits with bacteria and other traits with eukaryotes.
    • Some archaea are extremophiles, living in extreme environments.
    • Examples of extremophiles include:
      • Extreme halophiles (living in highly saline environments)
      • Extreme thermophiles (thriving in very hot environments)
      • Methanogens (strict anaerobes that produce methane as a waste product)

    Bacteria

    • Bacteria include the vast majority of prokaryotes.
    • Proteobacteria are gram-negative bacteria that include photoautotrophs, chemoautotrophs, and heterotrophs.
    • Some proteobacteria are anaerobic, while others are aerobic.
    • Cyanobacteria are photoautotrophs that generate O2.
    • Chlamydias are parasitic bacteria that live within animal cells.
    • Spirochetes are helical heterotrophs.
    • Gram-positive bacteria include:
      • Actinomycetes (decomposing soil)
      • Some Staphylococcus and Streptococcus (pathogenic)
      • Mycoplasms (the smallest known cells)

    Prokaryote Impact on Humans

    • Prokaryotes have both beneficial and harmful impacts on humans.
    • Some prokaryotes are human pathogens, while others have positive interactions with humans.
    • Mutualistic bacteria:
      • Live in human intestines (about 500-1,000 species)
      • Break down undigested food
    • Pathogenic bacteria:
      • Cause about half of all human diseases
      • Examples include Lyme disease
    • Pathogenic prokaryotes typically cause disease by releasing exotoxins or endotoxins.
    • Exotoxins are secreted and cause disease even if the prokaryotes are not present.
    • Endotoxins are released when bacteria die and their cell walls break down.

    Structure of Viruses

    • Viral genomes are classified as DNA or RNA viruses based on the type of nucleic acid.
    • Viral genomes may consist of:
      • Double- or single-stranded DNA
      • Double- or single-stranded RNA
    • Capsids are protein shells that enclose the viral genome.
    • Capsids can have various structures depending on the type of virus.
    • Capsids are built from protein subunits called capsomeres.
    • Many complex capsids are found among bacteriophages.
    • Phages are viruses that infect bacteria and have elongated capsid heads that enclose their DNA.
    • A protein tail piece attaches the phage to the host and injects the phage DNA inside.
    • Some viruses have membranous envelopes that help them infect hosts.
    • Viral envelopes contain a combination of viral and host cell molecules.
    • Examples of viruses with membranous envelopes include influenza viruses.

    Studying That Suits You

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

    Quiz Team

    Description

    This quiz covers the various structures found on the outer surface of the bacterial cell wall, including their functions and characteristics.

    More Like This

    Bacterial Cell Structure Quiz
    16 questions
    Prokaryotic Cell Surfaces and Structures
    37 questions
    Use Quizgecko on...
    Browser
    Browser