Chapter 1 — The Microbial World

The study of microorganisms and other microscopic biological agents.

The study of bacteria.

The study of viruses.

The study of fungi.

The study of parasites.

The study of protozoa.

The study of algae.

The study of the immune system and the body's defenses.

The study of how microorganisms interact with one another and their environments.

The study of microbial genes, heredity, and genetic variation.

The study of how microorganisms function.

The use of microorganisms to produce useful products.

The study of microorganisms that affect human health and cause disease.

The study of microorganisms in natural and built environments.

About 1 micrometer (\(\mu m\)).

About 10–100 micrometers (\(\mu m\)).

About 100 nanometers (nm), although sizes vary.

Viruses are generally smallest, followed by bacteria, then animal cells.

1,000 micrometers.

1,000 nanometers.

Bacteria, Archaea, and Eukarya.

Bacteria and Archaea.

Eukarya.

A cell that lacks a membrane-bound nucleus.

A cell that has a membrane-bound nucleus.

Generally, no.

Yes.

In a region called the nucleoid.

Fungi, algae, and protozoa.

Neither. Viruses are acellular and are not classified in the three domains of cellular life.

Bacterial cell walls usually contain peptidoglycan; archaeal cell walls do not.

A domain of unicellular prokaryotic organisms distinct from bacteria.

Organisms that thrive in environmental conditions considered extreme for most life.

Archaea that produce methane as part of their metabolism.

Organisms adapted to environments with very high salt concentrations.

Organisms adapted to high-temperature environments.

Organisms adapted to highly acidic environments.

No. Many archaea live in ordinary environments as well.

They contain ether-linked lipids with branched hydrocarbon chains.

The science of classifying, identifying, and naming organisms.

The two-part scientific naming system consisting of genus and species.

Carolus Linnaeus.

Capitalized and italicized.

Lowercase and italicized.

The genus is capitalized, the species name is lowercase, and both words are italicized.

The genus can be shortened to its initial, such as *E. coli*.

The particular species within a genus.

A genetic variant or subtype within a microbial species.

Capitalize *Staphylococcus*; lowercase *aureus*; italicize both.

Capitalize *Streptococcus*; lowercase *pneumoniae*; italicize both.

Capitalize *Mycobacterium*; lowercase *tuberculosis*; italicize both.

Capitalize *Vibrio*; lowercase *cholerae*; italicize both.

Capitalize *Bacillus*; lowercase *anthracis*; italicize both.

Capitalize *Clostridioides*; lowercase *difficile*; italicize both.

Capitalize *Aspergillus*; lowercase *niger*; italicize both.

Capitalize *Bacillus*; lowercase *thuringiensis*; italicize both.

A Dutch microscopist who was among the first to observe and describe living microorganisms.

Animalcules.

A scientist whose work established the role of microorganisms in fermentation and helped support germ theory.

Microbial growth in broth came from contamination by existing microorganisms, not spontaneous generation.

The disproven idea that living organisms can arise from nonliving matter.

The principle that living organisms arise from other living organisms.

Controlled heating used to reduce harmful microorganisms and spoilage organisms in a product.

A physician and microbiologist who linked specific microorganisms to specific diseases and developed important laboratory methods.

*Bacillus anthracis*.

A set of criteria historically used to connect a specific microorganism with a specific disease.

The suspected pathogen should be found in organisms with the disease and generally absent from healthy organisms.

The suspected pathogen should be isolated and grown in pure culture.

The cultured pathogen should cause the same disease when introduced into a susceptible healthy host.

The same pathogen should be recovered from the experimentally infected host.

Some pathogens cannot be grown in pure culture, some diseases have multiple causes, and some infected hosts show no symptoms.

The idea that specific microorganisms can cause infectious diseases.

A physician who developed an early smallpox vaccination method using material from cowpox lesions.

Exposure to a related, less dangerous infectious agent can protect against a more dangerous disease.

A physician who showed that handwashing greatly reduced childbed fever in maternity wards.

Handwashing with a disinfecting solution before patient contact.

A surgeon who promoted antiseptic surgical practices to reduce wound infections.

Carbolic acid, also called phenol.

A physician who used epidemiological investigation to link a cholera outbreak in London to contaminated water.

Disease patterns can be traced to a common source, such as a contaminated water supply.

A nurse and public-health reformer who used statistics and improved sanitation to reduce deaths in hospitals.

She promoted cleaner hospital conditions, better sanitation, and the use of data to improve patient care.

Antisepsis reduces or kills microbes on living tissue; asepsis aims to prevent microbial contamination.

Pasteur established important principles of microbial fermentation and germ theory; Koch developed methods to isolate pathogens and connect specific microbes to diseases.

His observations revealed that microscopic life existed.

His smallpox vaccination work helped establish the practice of vaccination.

They showed that hygiene and antiseptic practices could reduce infections.