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Microbiology Final Review Flashcards

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  • Goal of aseptic technique
    To prevent contamination of cultures, media, and the environment by unwanted microorganisms.
  • Define ubiquity in microbiology
    The concept that microorganisms are found everywhere in the environment.
  • Pure culture versus mixed culture
    Pure culture contains only one type of microorganism; mixed culture contains two or more different microorganisms.
  • Quadrant streak plate method
    A technique to isolate individual bacterial colonies by sequentially streaking four quadrants on an agar plate.
  • Purpose of heat fixation in smear preparation
    To kill the bacteria, fix them to the slide, and preserve cellular structures for staining.
  • Gram stain cell wall differences
    Gram-positive bacteria have thick peptidoglycan layers; Gram-negative bacteria have thin peptidoglycan and an outer membrane.
  • Function of a bacterial capsule
    Protects bacteria from desiccation, phagocytosis, and helps in adherence to surfaces.
  • Characteristics of bacterial endospores
    Highly resistant, dormant structures formed to survive harsh conditions.
  • Effect of pH on microbial growth
    Microbes have optimal pH ranges; deviations can inhibit metabolism and growth.
  • Terminology for temperature classifications of microbes
    Psychrophiles: cold-loving; mesophiles: moderate temperature; thermophiles: heat-loving.
  • Anaerobic jar purpose
    To create an oxygen-free environment for growing anaerobic bacteria.
  • Difference between disinfection and sterilization
    Disinfection reduces microbial load; sterilization completely removes or kills all microorganisms.
  • Ionizing vs non-ionizing radiation in microbial control
    Ionizing radiation penetrates cells causing DNA damage; non-ionizing (UV) causes surface DNA damage.
  • Disk diffusion method
    A test to evaluate antimicrobial effectiveness by measuring inhibition zones around antibiotic disks.
  • Difference between antimicrobials and antibiotics
    Antimicrobials include all agents that kill or inhibit microbes; antibiotics are natural or synthetic drugs targeting bacteria.
  • Broad spectrum vs narrow spectrum antibiotics
    Broad spectrum target many bacteria types; narrow spectrum target specific groups.
  • Herd immunity
    When a high percentage of a population is immune, reducing disease spread.
  • R0 (reproductive number)
    The average number of secondary infections produced by one infected individual.
  • Difference between incidence and prevalence
    Incidence is the number of new cases; prevalence is the total number of cases at a given time.
  • Purpose of selective and differential media
    Selective media inhibit unwanted microbes; differential media distinguish microbes based on biochemical traits.
  • Catalase test purpose
    Detects the enzyme catalase by breaking down hydrogen peroxide into water and oxygen.
  • MacConkey agar use
    Selective for Gram-negative bacteria and differential for lactose fermentation.
  • ELISA in serology
    A test that uses antibodies and color change to detect antigens or antibodies in samples.
  • Steps to identify unknown microbes
    Observe morphology, perform staining, biochemical tests, and compare results to identification charts.