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Microbiology Key Concepts and Definitions

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Termini in questo insieme (29)

  • Bacteria

    Unicellular prokaryotes with cell walls generally containing peptidoglycan.

  • Archaea

    Unicellular prokaryotes whose cell walls do not contain peptidoglycan.

  • Fungi

    Eukaryotic organisms; molds are multicellular filaments, yeasts are unicellular.

  • Protozoa

    Single-celled eukaryotes that often move by pseudopods, cilia, or flagella.

  • Viruses

    Non-cellular entities that infect cellular hosts and are important in microbiology.

  • Pasteur's Swan-Neck Flask Experiment

    Allowed air in but trapped dust, preventing microbial contamination and disproving spontaneous generation.

  • Koch's Postulates
    1. Agent found in diseased but not healthy hosts.
    2. Agent isolated and grown in pure culture.
    3. Agent causes disease in healthy host.
    4. Agent re-isolated from experimentally infected host.
  • Anabolism

    Metabolic process of synthesis where smaller molecules form larger ones, requiring energy.

  • Catabolism

    Metabolic process of decomposition where large molecules break down, releasing energy.

  • Water in Microbiology

    Most abundant substance in organisms; excellent solvent; liquid over wide temperatures; absorbs heat; participates in reactions.

  • Lipids

    Hydrophobic macromolecules including fats, phospholipids, waxes, and steroids; phospholipids form membranes.

  • Proteins

    Polymers of amino acids joined by peptide bonds; functions include structure, catalysis, regulation, transport, defense, and offense.

  • Nucleotides

    Building blocks of nucleic acids; composed of phosphate, pentose sugar, and nitrogenous base.

  • DNA Base Pairing

    C–G pairs form 3 hydrogen bonds; A–T pairs form 2 hydrogen bonds; DNA strands are complementary and antiparallel.

  • Prokaryotic vs. Eukaryotic Cells

    Prokaryotes lack nucleus and membrane-bound organelles; eukaryotes have both and are larger in size.

  • Bacterial Capsule

    Organized glycocalyx firmly attached; helps bacteria avoid host immune recognition.

  • Flagellum Function

    Provides bacterial movement via rotation of filament, hook, and basal body.

  • Gram-Positive vs. Gram-Negative Cell Walls

    Gram-positive have thick peptidoglycan and teichoic acids; Gram-negative have thin peptidoglycan and outer membrane with LPS.

  • Lipid A

    Component of LPS in Gram-negative bacteria; can cause fever, inflammation, shock, and clotting.

  • Endospores

    Survival structures formed by some bacteria; resistant to heat, radiation, and chemicals; not reproductive.

  • Microscope Resolution

    Ability to distinguish two close points as separate; improved by oil immersion in light microscopy.

  • Gram Stain Result

    Gram-positive cells stain purple; Gram-negative cells stain pink after counterstaining.

  • Taxonomy

    Includes classification, nomenclature, and identification of organisms; Linnaeus introduced binomial nomenclature.

  • Biochemical Tests

    Identify microbes based on ability to use or produce specific chemicals.

  • Serological Tests

    Use antigen–antibody reactions to identify microbes.

  • Endosymbiotic Theory

    Mitochondria and chloroplasts descended from free-living prokaryotes; supported by their DNA, 70S ribosomes, and double membranes.

  • Phospholipid Bilayer

    Structure of bacterial cytoplasmic membrane; selectively permeable and fluid mosaic model applies.

  • Active Transport

    Transport across membrane requiring cellular energy to move substances against gradients.

  • Dichotomous Key

    Identification tool using paired either/or statements leading stepwise to organism identification.