Microbiology BIOS 2460 Exam 1 Review

Vocabulary terms and definitions from Chapters 1, 3, 4, and 5 of the Microbiology BIOS 2460 lecture notes.

Ubiquity

The state or capacity of being everywhere; in microbiology, it refers to the fact that microorganisms are found in nearly every environment on Earth.

Pathogen

A microorganism or agent that causes disease.

Parasite

An organism that lives on or in a host organism and gets its food from or at the expense of its host.

Prokaryotes

Microscopic, unicellular organisms that lack a nucleus and membrane-bound organelles.

Eukaryotes

Organisms whose cells contain a nucleus and other membrane-bound organelles; can be unicellular or multicellular.

Abiogenesis

The historical belief that living things could arise from non-living matter, also known as spontaneous generation.

Germ Theory

A theory describing the role of microorganisms in causing specific diseases.

Binomial system

The method of assigning a scientific name to an organism using two terms: the genus (capitalized) and the species (lowercase), both usually italicized or underlined.

Woese-Fox system

A classification system that organizes life into three primary Domains: Bacteria, Archaea, and Eukarya.

The 6 ‘I’s

The basic techniques used to manipulate, grow, examine, and characterize microorganisms: Inoculation, Incubation, Isolation, Inspection, Information gathering, and Identification.

Agar

A complex polysaccharide isolated from the alga Gelidium used as a solidifying agent in culture media because it is not digestible by most microbes.

Selective media

Nutrient media designed to favor the growth of certain microbes while inhibiting the growth of others.

Differential media

Media that allow multiple types of microorganisms to grow but are designed to display visible differences (such as color) among them.

Fastidious organisms

Bacteria that require specific growth factors and complex organic substances (like blood or vitamins) to grow.

Enriched medium

A medium containing organic substances such as blood, serum, or special growth factors required by fastidious organisms.

Resolving power

The ability of a microscope to show detail; the capacity to distinguish two adjacent objects as separate.

Pure culture

A container of medium that grows only a single known species or type of microorganism.

Mixed culture

A container that holds two or more easily differentiated species of microorganisms.

Contaminated culture

A culture that was once pure or mixed but has since had unwanted microbes introduced into it.

Chemotaxis

The movement of a cell toward or away from a chemical stimulus.

Monotrichous

A term describing a bacterial cell with a single flagellum at one end.

Biofilm

A complex association of microorganisms that grow on surfaces and are held together by a sticky matrix.

Peptidoglycan

A network of polysaccharide chains cross-linked by short peptides that forms the rigid cell wall of most bacteria.

Plasmid

Small, circular, double-stranded DNA molecules in bacteria that are distinct from the main chromosome and often carry genes for antibiotic resistance.

Endospore

A dormant, highly resistant structure formed by certain bacteria to survive extreme environmental conditions.

Pleomorphism

The ability of some bacteria to alter their shape or size in response to environmental conditions.

9 + 2 arrangement

The structural pattern of microtubules found in eukaryotic flagella and cilia, consisting of nine pairs of peripheral microtubules surrounding two central microtubules.

Opportunistic pathogen

A microbe that typically does not cause disease in a healthy host but can become pathogenic if the host's immune system is compromised.

Dimorphic (biphasic) fungi

Fungi that can exist in two forms, typically as a yeast at higher temperatures ($37\,^{\circ}\text{C}$) and as a mold at lower temperatures ($25\,^{\circ}\text{C}$).

Hyphae

Long, thread-like branching filaments that make up the body of a fungus or mold.

Mycelium

The mass of interwoven hyphae that forms the vegetative body of a fungus.

Protozoan cysts

A dormant, resting stage of a protozoan that provides protection against harsh environmental conditions and a means of survival outside the host.

Helminths

Parasitic worms such as tapeworms, flukes, and roundworms.

Filarial nematodes

Roundworms that live in the blood or lymph and are usually transmitted by insects.