Chapter 1: Introduction to Microbiology

Comprehensive vocabulary flashcards covering introductory concepts in microbiology, including microbial taxonomy, human microbiome relationships, cellular domains, and historical experiments in spontaneous generation and germ theory.

Microorganisms

Organisms that are too small to be seen with the unaided eye.

Microbiome

A group of microbes that live stably on or inside the human body, helping to maintain health, prevent growth of pathogenic microbes, and train the immune system.

Commensalism

A host-microbe relationship in which the microbe is innocuous to the host.

Mutualism

A host-microbe relationship that provides beneficial outcomes for both the host and the microorganism.

Pathogen

An infectious or parasitic microorganism that causes disease in a host.

Opportunistic Pathogen

A commensal microorganism that becomes pathogenic under specific conditions, such as in an immunocompromised host, genetic susceptibility, displacement from its normal niche, or following an antibiotic course.

Microbial Flora

The collection of acquired microorganisms established on or in a healthy human being.

Bioremediation

The environmental use of organisms, such as prokaryotic decomposers, to remove pollutants from water, air, and soil.

Scientific Nomenclature

The system established by Linnaeus that assigns each organism two Latinized names worldwide: a capitalized Genus name and a lowercase species epithet.

Bacilli

Rod-shaped bacterial cells.

Cocci

Spherical-shaped bacterial cells.

Spirochetes

Spiral-shaped bacterial cells.

Peptidoglycan

The chemical substance forming the cell wall exterior to the plasma membrane in bacteria.

Biofilm

A highly organized colony consisting of one or several species of prokaryotes attached to a surface such as rocks, metal, plastic, or teeth.

Archaea

Domain of single-celled prokaryotic organisms that lack peptidoglycan in their cell walls and frequently inhabit extreme environments.

Methanogens

A group of Archaea that produce methane gas as a metabolic byproduct.

Extreme Halophiles

Archaea that thrive in environments containing extremely high concentrations of salt.

Extreme Thermophiles

Archaea that survive and thrive in environments with extremely high temperatures.

Fungi

Eukaryotic organisms with chitin cell walls that obtain energy from organic chemicals; includes multicellular molds and mushrooms, and unicellular yeasts.

Hyphae

Filaments that collectively form the mycelia in multicellular fungi such as molds.

Algae

Photosynthetic eukaryotic organisms with cellulose cell walls that produce molecular oxygen and organic compounds.

Protozoa

Unicellular eukaryotic organisms that absorb or ingest organic chemicals and may move via pseudopods, cilia, or flagella.

Helminths

Multicellular animal parasites, including parasitic flatworms such as Taenia solium and roundworms such as pinworms.

Viruses

Acellular, obligate parasites composed of a DNA or RNA nucleic acid core surrounded by a protein coat (capsid), reproducing only within living host cells.

Capsid

The outer protein coat that surrounds the genetic nucleic acid core of a virus.

Cell Theory

The biological principle stating that all living things are composed of cells and arise from preexisting cells.

Spontaneous Generation

The hypothesis that living organisms can originate spontaneously from nonliving matter via a vital force.

Biogenesis

The hypothesis that living organisms arise exclusively from preexisting living cells.

Francesco Redi

Italian scientist who performed experiments in $1668$ using covered and open jars of decaying meat to demonstrate that maggots do not spontaneously generate.

John Needham

Scientist who argued in favor of spontaneous generation in $1745$ after observing microbial growth in heated nutrient broth that was cooled before being covered.

Lazzaro Spallanzani

Scientist who challenged spontaneous generation in $1765$ by sealing nutrient broth in flasks prior to heating, resulting in no microbial growth.

Louis Pasteur

French scientist who disproved spontaneous generation in $1861$ using S-shaped flasks, demonstrated microbes in air, and introduced fermentation, pasteurization, and vaccination principles.

Fermentation

The microbial conversion of sugars into alcohol to produce beer and wine, or into acids that cause food spoilage.

Pasteurization

The process of applying heat for a short time to kill spoilage and disease-causing bacteria in beverages and food products.

Germ Theory of Disease

The principle that infectious diseases are caused by specific microorganisms.

Ignaz Semmelweis

Physician who advocated handwashing in the $1840\text{s}$ to prevent the transmission of puerperal fever.

Koch's Postulates

A series of experimental steps provided by Robert Koch in $1876$ to demonstrate that a specific microbe causes a specific disease.