Introduction to Microbiology and Beneficial Microorganisms

These vocabulary flashcards cover the history of microbiology, the different types of microorganisms, their habitats, and their beneficial roles in industry, food, and the environment.

Microbiology

The study of microorganisms, which are microscopic organisms visible only with a microscope.

Microbial cell size

Microbial cells are typically very small, measuring approximately $1\text{ μm}$ in size.

Robert Hooke

An English natural philosopher (1635–1703) who published Micrographia in 1665, the first book devoted to microscopic observations, and made the first drawing of microorganisms (mould on leather).

Antonie van Leeuwenhoek

Known as the "father of microbiology" (1632–1723), he improved optical lenses and was the first to publish drawings of bacteria in 1684, which he called "animalcules."

Louis Pasteur

A French scientist (1822–1895) who disproved spontaneous generation using swan-necked flasks and contributed to discoveries in vaccination, fermentation, and pasteurisation.

Spontaneous generation

The disproved theory that living organisms emerge spontaneously from non-living matter.

Robert Koch

A German scientist (1843–1910) who developed four criteria (postulates) for proving cause and effect in infectious diseases, founding the principles of Medical Microbiology.

Angelina Fanny Hesse

Suggested the use of agar instead of gelatin for culturing microorganisms because it maintains gel properties at warm temperatures.

The three domains of life

Bacteria, Archaea, and Eukarya; Archaea were classified as a separate domain by Carl Woese in 1977.

Prokaryotes

Single-celled organisms, including Bacteria and Archaea, which lack a nucleus and membrane-enclosed organelles.

Eukaryotes

Organisms whose cells contain DNA in a nucleus and have membrane-enclosed organelles such as mitochondria and chloroplasts.

Viruses

Acellular entities consisting of nucleic acids and proteins that are not living organisms because they cannot grow independently and require a host for replication.

Binomial nomenclature

The scientific naming system where the Genus and species are always in italics (e.g., Escherichia coli), with the Genus capitalized and the species in lowercase.

Bacteria

Prokaryotic organisms with peptidoglycan cell walls that multiply by binary fission and are phylogenetically and metabolically diverse.

Archaea

Prokaryotic organisms that lack peptidoglycan in their cell walls and often inhabit extreme environments, such as high salt (halophiles) or high temperature (thermophiles).

Fungi

Eukaryotic organisms with chitin cell walls; they include unicellular yeasts and multicellular moulds or mushrooms.

Cyanobacteria

Prokaryotic blue-green algae that are oxygenic phototrophs and were responsible for oxygenating the Earth's atmosphere.

Protozoa (Protists)

Single-celled eukaryotes that cannot photosynthesise, instead absorbing or ingesting organic matter; they may be motile via pseudopods, cilia, or flagella.

Microbial ecology

The study of complex microbial communities and their interactions with one another and their environment.

Extremophiles

Microorganisms that survive under extreme conditions, such as very high or low temperatures, altitudes, depths, or acidic/alkaline environments.

Normal microflora

The population of microorganisms, mostly benign, that inhabit the human body, numbering approximately 40 trillion cells.

Anoxic atmosphere

The state of Earth's atmosphere for its first 2 billion years, where $O_2$ was absent and only anaerobic microorganisms could grow.

Rhizobium

A genus of symbiotic nitrogen-fixing bacteria found in the root nodules of legumes that convert atmospheric $N_2$ to $NH_3$.

Mycorrhiza

A symbiotic association between plant roots and fungi where the fungi provide phosphorus and the plants provide carbohydrates.

Rumen

A digestive organ in animals like cattle and sheep containing large microbial populations that convert cellulose from grass into fatty acids.

Saccharomyces cerevisiae

A single-cell yeast used in baking and alcoholic beverage production through fermentation, which generates alcohol and $CO_2$.

Lactic acid fermentation

A process carried out by bacteria such as Lactobacillus and Streptococcus to produce yogurt, cheese, sauerkraut, and kimchi.

Probiotics

Live bacteria and yeasts, such as Lactobacillus casei, promoted as "good" bacteria for various health benefits.

Botulinum toxin

A neurotoxin produced by Clostridium botulinum that causes flaccid paralysis; used in tiny amounts for BOTOX treatments.

Bioremediation

The process by which microorganisms are used to clean up environmental pollutants, such as oil spills or toxic solvents.

Taq polymerase

A thermostable DNA polymerase first isolated from the thermophilic bacterium Thermus aquaticus, used in PCR techniques.

CRISPR-CAS

A bacterial immune system discovered in 2010–2012 that has been adapted as a tool for targeted genome editing.

Model organisms

Species such as Escherichia coli and Saccharomyces cerevisiae that are well-characterized, easy to manipulate, and used to study fundamental biological processes.