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Nitrogen Fixation exam Flashcards

Nitrogen Fixation exam
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  • Nitrogen Fixation
    The process by which bacteria convert atmospheric nitrogen (N2) into ammonia (NH3), making it usable for plants.
  • Why is nitrogen essential for living organisms?
    Nitrogen is a required element in both nucleic acids and proteins.
  • Ammonium (NH4+)
    A form of nitrogen absorbed by plants, derived from ammonia.
  • What percentage of the atmosphere is nitrogen gas (N2)?
    Approximately 78%.
  • Nitrates (NO3-)
    Another form of nitrogen absorbed by plants, produced through various chemical reactions.
  • Rhizobia
    Gram-negative soil bacteria that perform nitrogen fixation in the roots of legumes.
  • What is the role of mycorrhizae in nitrogen absorption?
    Mycorrhizae are symbiotic fungi that enhance nutrient absorption, including nitrogen, for plants.
  • Leghemoglobin
    A molecule produced by legumes to bind oxygen and protect nitrogenase from oxygen poisoning.
  • What is the energy requirement for converting one molecule of N2 into ammonia?
    16 ATP and 8 high-energy electrons.
  • Nitrogenase
    The enzyme complex that facilitates the conversion of gaseous nitrogen (N2) into ammonia (NH3).
  • What are nodules in legume roots?
    Swollen nodes where rhizobia bacteria infect the plant roots to perform nitrogen fixation.
  • Carnivorous Plants
    Plants that supplement their nitrogen intake by consuming animals.
  • What is the nitrogen cycle?
    A chemical cycle in which nitrogen is converted through various forms, making it available to living organisms.
  • Ectomycorrhizae
    A type of mycorrhizae where fungal hyphae wrap around plant cells but do not penetrate them.
  • What is the role of decomposers in the nitrogen cycle?
    Decomposers break down organic matter, releasing ammonium and other forms of nitrogen into the soil.
  • Arbuscular Mycorrhizae
    A type of mycorrhizae where fungal hyphae penetrate the cortical cells of plant roots.
  • What are flavonoids?
    Chemicals released by plant roots to attract rhizobia bacteria.
  • Endophytes
    Organisms, usually fungi or bacteria, that live inside other plants.
  • How do plants benefit from rhizobia bacteria?
    Rhizobia provide usable nitrogen to plants in exchange for carbohydrates and protection.
  • Nitrogen Cycle
    The process by which nitrogen is converted between its various chemical forms, involving processes like nitrogen fixation and decomposition.
  • What is the main form of nitrogen in the atmosphere?
    Nitrogen gas (N2).
  • Detritivores
    Organisms that break down dead organic matter, contributing to the nitrogen content in the soil.
  • What is the role of nitrogen in nucleic acids?
    Nitrogen is a key component of nucleotides, the building blocks of DNA and RNA.
  • Symbiotic Relationship
    A mutually beneficial relationship between two different organisms, such as plants and rhizobia.
  • How do epiphytes obtain nitrogen?
    Epiphytes absorb water and nutrients, including nitrogen, from the air, rain, and debris around them.
  • Nitrogenase Complex
    A multi-enzyme complex that reduces gaseous nitrogen (N2) to ammonia (NH3) during nitrogen fixation.
  • What is the function of nod factors?
    Signals released by rhizobia bacteria to stimulate root hair changes, allowing bacterial entry into the plant.
  • Mutualistic Relationship
    A type of symbiotic relationship where both organisms benefit, such as plants and nitrogen-fixing bacteria.