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Nutritional Factors of Microbial Growth quiz

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  • What are the three main nutritional factors used to classify microorganisms?
    The three main nutritional factors are energy source, electron source, and carbon source.
  • How are organisms classified based on their energy source?
    Organisms are classified as phototrophs if they use sunlight for energy, and chemotrophs if they use chemical compounds.
  • What is a phototroph?
    A phototroph is an organism that obtains its energy directly from sunlight.
  • What is a chemotroph?
    A chemotroph is an organism that obtains its energy from chemical compounds in its environment.
  • How are organisms classified based on their electron source?
    Organisms are classified as lithotrophs if they use inorganic molecules for electrons, and organotrophs if they use organic molecules.
  • What is a lithotroph?
    A lithotroph is an organism that obtains electrons from reduced inorganic molecules, such as water or iron.
  • What is an organotroph?
    An organotroph is an organism that obtains electrons from organic molecules containing carbon and hydrogen, such as glucose.
  • How are organisms classified based on their carbon source?
    Organisms are classified as autotrophs if they fix inorganic carbon (like CO2) to make their own food, and heterotrophs if they consume organic molecules for carbon.
  • What is an autotroph?
    An autotroph is an organism that uses carbon fixation to capture inorganic carbon, usually CO2, to make its own food.
  • What is a heterotroph?
    A heterotroph is an organism that consumes organic molecules to obtain carbon for building cell components.
  • What is a chemolithoautotroph?
    A chemolithoautotroph is an organism that uses chemical energy, inorganic molecules as an electron source, and fixes inorganic carbon (CO2) for its carbon source.
  • What is a photoorganoheterotroph?
    A photoorganoheterotroph is an organism that uses light for energy, organic molecules for electrons, and organic molecules for its carbon source.
  • Can all combinations of energy, electron, and carbon sources exist in nature?
    All combinations are theoretically possible, but some have no known existing organisms.
  • Why are plants considered lithotrophs?
    Plants are lithotrophs because they harvest electrons from splitting water, an inorganic molecule, during carbon fixation.
  • How does understanding nutritional classifications help in microbiology?
    Understanding these classifications helps explain microbial diversity and their ecological roles.