Microbiology BIO 120 – Quiz 1 Vocabulary Review

Seventy vocabulary flashcards covering key microbiology terms, concepts, and scientists for BIO 120 Quiz 1 preparation.

Pathogen

A disease-causing organism.

Smog

Fog combined with smoke or other atmospheric pollutants.

Fermentation

Enzymatic degradation of carbohydrates in which the final electron acceptor is an organic molecule, ATP is made by substrate-level phosphorylation, and oxygen is not required.

Desiccation

The removal of water from a substance or organism.

Plasmolysis

Shrinkage of a cell’s cytoplasm due to water loss in a hypertonic environment.

Osmotic lysis

Rupture of the plasma membrane caused by excessive water entry into the cell.

Hydrolysis

A decomposition reaction in which a chemical compound reacts with the H⁺ and OH⁻ of a water molecule.

Mycology

The scientific study of fungi.

Isotonic solution

A solution that produces no net movement of water across a cell membrane because osmotic pressure is equal inside and outside the cell.

Hypotonic solution

A solution with a lower solute concentration than inside the cell, causing water to move into the cell.

Hypertonic solution

A solution with a higher solute concentration than inside the cell, causing water to move out of the cell.

Aerotolerant anaerobe

An organism that does not use oxygen for growth but can tolerate its presence.

Microaerophile

A microorganism that grows best in environments containing lower levels of oxygen than are found in the atmosphere.

Binary fission

Prokaryotic cell reproduction by division into two genetically identical daughter cells.

Endospore

A resistant, dormant structure formed inside some bacteria; not easily stained by ordinary methods.

Thermal death time (TDT)

The minimal time required to kill all bacteria in a liquid culture at a specific temperature.

Thermophile

A heat-loving microbe whose optimum growth temperature is between 50 °C and 60 °C.

Capnophile

A microorganism that grows best at relatively high CO₂ concentrations.

Human microbiome

The community of microorganisms that live in and on the human body, influencing health and disease.

Microscopic resolution

The ability of a microscope to distinguish fine detail; also called resolving power.

Biogenesis

The theory that living cells arise only from pre-existing cells.

Spontaneous generation

The disproven idea that life can arise from non-living matter.

Pasteurization

A process of mild heating that kills pathogenic and spoilage microorganisms.

Binomial nomenclature

The formal system of naming organisms, established by Carolus Linnaeus.

Eukaryote

A cell that possesses a true nucleus and membrane-bound organelles.

Prokaryote

A cell lacking a nuclear membrane; includes Bacteria and Archaea.

Three-domain system

A classification that divides life into Bacteria, Archaea, and Eukarya.

Archaea

Prokaryotes without peptidoglycan walls, often inhabiting extreme environments and not known to cause human disease.

Bacteria

Prokaryotes with peptidoglycan cell walls; widely distributed in nature.

Koch’s postulate

The principle stating that a specific microbe causes a specific disease.

Capsule

A gelatinous, dye-resistant covering around some bacteria that helps them avoid phagocytosis.

Active transport

Movement of substances across a membrane using energy (ATP) against a concentration gradient.

Passive transport

Movement of substances across a membrane without energy expenditure.

Differential staining

Staining procedures, such as Gram or acid-fast staining, that distinguish between different types of cells.

Gram stain

A differential stain that classifies bacteria as Gram-positive or Gram-negative.

Acid-fast stain

A differential stain used primarily to detect Mycobacterium and Nocardia species.

Crystal violet

The primary purple dye applied in the first step of the Gram stain.

Iodine (mordant)

The Gram-stain reagent that forms a complex with crystal violet, fixing it inside the cell wall.

Decolorizer

Alcohol or acetone step in the Gram stain that removes dye from Gram-negative cells.

Safranin

The red counterstain in the Gram procedure that colors Gram-negative bacteria pink/red.

Edward Jenner

Physician credited as the founder of modern vaccination using cowpox to prevent smallpox.

Alexander Fleming

Scientist who discovered the first antibiotic, penicillin, produced by Penicillium fungus.

Electron microscope

A microscope that uses electrons instead of light, achieving the highest resolution.

Transmission electron microscope (TEM)

Type of electron microscope that reveals internal structures of microbes.

Recombinant DNA technology

Laboratory methods used to recombine genetic material to produce proteins, vaccines, and enzymes.

Normal microbiota

Microbes that permanently colonize the body without normally causing disease.

Cerebrospinal fluid (CSF)

A body fluid that is normally sterile, along with blood.

Gram-positive cell wall

A thick peptidoglycan layer that retains crystal violet and lacks an outer membrane.

Gram-negative cell wall

A thin peptidoglycan layer plus an outer membrane containing lipopolysaccharide and endotoxin.

Osmosis

Passive movement of water across a selectively permeable membrane from low solute to high solute concentration.

Diffusion

Passive movement of molecules from an area of higher to lower concentration.

Facilitated diffusion

Passive transport of molecules across a membrane via specific carrier proteins.

Primary active transport

ATP-powered movement of ions or molecules, exemplified by the Na⁺/K⁺ pump.

Secondary active transport

Transport that uses the energy stored in ion gradients, such as the Na⁺-glucose symporter.

Endocytosis

Active process in which a cell engulfs material by folding the plasma membrane inward to form vesicles.

Exocytosis

Active process in which intracellular vesicles fuse with the plasma membrane to release contents outside the cell.

Coccus

A spherical bacterial shape.

Bacillus

A rod-shaped bacterium.

Spirillum

A rigid spiral or helical bacterial shape.

Chain arrangement (Strepto-)

Cells that remain attached in long chains after division.

Cluster arrangement (Staphylo-)

Cells that divide in multiple planes and remain in grape-like clusters.

Pair arrangement (Diplo-)

Cells that remain in pairs following division.

Biosafety Level 1 (BSL-1)

Laboratory level for microbes not known to consistently cause disease in healthy adults.

Biosafety Level 2 (BSL-2)

Laboratory level for moderate-risk microbes such as Salmonella and herpes simplex virus.

Biosafety Level 3 (BSL-3)

Laboratory level for indigenous or exotic microbes that may cause serious or lethal disease via inhalation, e.g., Mycobacterium tuberculosis.

Biosafety Level 4 (BSL-4)

Highest laboratory containment for high-risk, aerosol-transmitted agents like Ebola virus.

Lag phase

Initial period of intense metabolic activity with no increase in cell number.

Log phase

Period of logarithmic (exponential) increase in bacterial population.

Stationary phase

Stage where microbial deaths equal new cell production; population size stabilizes.

Death phase

Period where the number of dying cells exceeds the number of new cells; population declines logarithmically.