History of Microbiology – Core Vocabulary

This set of vocabulary flashcards covers the foundational terms and concepts introduced in the lecture notes on the history and basics of microbiology, including microbial types, disease terminology, and key characteristics of bacteria and archaea.

Microbe

A microscopic organism capable of converting one chemical substance into another due to diverse metabolic capabilities.

Prokaryote

An organism lacking a true nucleus; its DNA/RNA is not enclosed within a nuclear membrane.

Eukaryote

An organism whose genetic material is enclosed within a true nucleus.

Pathogenic Microorganism

A microbe that can invade a host and cause disease (e.g., Plasmodium in malaria).

Parasite

A microbe adapted to a non-free-living lifestyle, residing on or in a host.

Infectious Disease

Illness resulting from a pathogen invading a susceptible host with weakened barriers or immunity.

Mortality

The death rate within a population.

Morbidity

The state or condition of having a significant illness or disease.

Normal Microbiota

Microorganisms that live on or in the human body without causing harm, often providing protection by competing for nutrients.

Transient Flora

Microbes that are present temporarily on body surfaces.

Resident Flora

Microbes that are consistently present on or in the body.

Emerging Infectious Disease

A newly identified or changing disease with increasing incidence (e.g., SARS-CoV-2, Zika).

Reemerging Infectious Disease

An older, well-known disease that is resurging in frequency (e.g., tuberculosis, cholera).

Zoonotic Disease

An infection transmissible from animals to humans, often linked to agricultural practices.

Microbiology

The scientific study of microorganisms (microbes).

Microscopic Scale

Objects measuring roughly 1 millimetre or less in size.

Ubiquitous

Existing everywhere; describes the widespread presence of microbes in soil, water, air, etc.

Bacterium

A small, single-celled prokaryote with genetic material not enclosed by a nuclear membrane and a peptidoglycan cell wall.

Coccus

A spherical bacterial shape.

Bacillus

A rod-shaped bacterial form.

Spiral (Bacterial)

A corkscrew-shaped bacterium.

Peptidoglycan

A structural polysaccharide-peptide compound forming most bacterial cell walls.

Binary Fission

Asexual reproduction in bacteria in which one cell divides into two identical cells.

Flagellum

A whip-like appendage providing motility to many bacteria (e.g., Gram-negative bacilli with flagella).

Archaea

Prokaryotes whose cell walls lack peptidoglycan, possessing unique rRNA sequences and membrane lipids, often inhabiting extreme environments.

Methanogen

An anaerobic archaeon that produces methane as a metabolic by-product.

Halophile

A salt-loving archaeon thriving in high-salinity environments such as the Dead Sea.

Extreme Thermophile

An archaeon that lives only in very high-temperature environments inhospitable to most life.

Distinct rRNA Sequencing (Archaea)

Unique ribosomal RNA sequences that differentiate archaea from bacteria and eukaryotes.

Unique Membrane Lipids (Archaea)

Specialized lipid structures in archaeal membranes that confer stability in extreme conditions.