The Evolution of Microorganisms and Microbiology

Vocabulary flashcards covering the definitions, types, history, and key figures in the evolution of microbiology.

Microorganisms

Organisms generally smaller than $1\,mm$ that are too small to be clearly seen by the unaided eye, are simple in construction, and lack differentiated tissues.

Cellular Microbes

Organisms and biological entities studied by microbiologists that include Fungi, Protists, Bacteria, and Archaea.

Acellular Microbes

Biological entities that are not composed of cells, including Viruses, Viroids, Satellites, and Prions.

Three-domain system

A classification scheme for microorganisms based on a comparison of ribosomal $RNA$ genes, consisting of Bacteria, Archaea, and Eukarya.

Prokaryotic cells

Cells characterized by an "open floor plan" that lack a membrane-enclosed nucleus.

Eukaryotic cells

Cells that contain a membrane-enclosed nucleus and are generally larger and more morphologically complex than prokaryotic cells.

Bacteria

Usually single-celled organisms, most of which have cell walls containing peptidoglycan and lack a membrane-bound nucleus.

Archaea

A domain of microorganisms distinguished from Bacteria by unique $rRNA$ sequences and unique membrane lipids that do not directly cause disease in humans.

Protists

Unicellular Eukarya that are generally larger than Bacteria and Archaea, encompassing photosynthetic Algae and animal-like Protozoa.

Fungi

Eukaryotic organisms that can be unicellular (Yeasts) or multicellular (Molds and Mushrooms).

Viruses

Acellular agents composed of protein and nucleic acid.

Viroids

Acellular agents composed only of $RNA$.

Satellites

Acellular agents composed of nucleic acid enclosed in a protein shell.

Prions

Acellular agents composed entirely of protein.

Spontaneous generation

The discredited idea that living organisms can develop from nonliving or decomposing matter.

Francesco Stelluti

The individual who performed the earliest microscopic observations on bees and weevils between 1625 and 1630.

Robert Hooke

Author of the 1665 book Micrographia, which featured drawings of the fungus Mucor.

Antony van Leeuwenhoek

The first person to accurately observe microorganisms, which he called "animalcules," between 1674 and 1676.

Swan-neck flask experiments

Experiments conducted by Louis Pasteur in 1861 that helped disprove spontaneous generation by showing that heat-sterilized broth remained sterile when air was allowed in through a curved neck that trapped dust.

John Tyndall

A scientist who demonstrated that dust carries microorganisms and provided evidence for the existence of exceptionally heat-resistant bacteria.

Ferdinand Cohn

A scientist who demonstrated that heat-resistant bacteria could produce endospores.

Humors

The four bodily fluids (blood, phlegm, yellow bile, and black bile) whose imbalance was formerly believed to cause disease.

Agostino Bassi

The scientist who showed in the early 19th century that a disease of silkworms was caused by a fungus.

Joseph Lister

A surgeon who developed an antiseptic surgery system to prevent microorganisms from entering wounds, providing indirect evidence for the germ theory of disease.

Koch’s postulates

The experimental criteria published in 1884 to establish the causal relationship between a specific microorganism and a specific disease.

Attenuated cultures

Pathogenic cultures that have lost their ability to cause disease through long incubation intervals, used by Pasteur and Roux to develop vaccines.

Pure culture

An isolated strain of a microorganism grown in a laboratory.

Medical microbiology

The branch of microbiology concerned with diseases of humans and animals.

Immunology

The study of how the immune system protects a host from pathogens.

Industrial microbiology

The field that uses microbes to manufacture products such as antibiotics, vaccines, steroids, and biofuels.