MICROBIAL GROWTH, NUTRITION, AND ENVIRONMENT VOCABULARY FLASHCARDS

Vocabulary-style flashcards covering key terms from microbial physiology, growth, nutrition, and environmental factors.

Microbial physiology

The study of the vital life processes of microorganisms.

Microbial growth

Increase in a population of microbes.

Biofilm

A surface-attached microbial community embedded in an extracellular matrix.

Glycocalyx

A capsule-like layer aiding attachment and protection; common in biofilm-forming bacteria.

Quorum sensing

Cell-density–dependent signaling that coordinates communal behaviors like biofilm formation.

Antagonistic relationship

One organism benefits while harming another.

Synergistic relationship

Two or more organisms yield a combined effect greater than the sum of their individual effects.

Commensalism

One organism benefits while the other is unaffected.

Satellism

Growth of one species enhanced by another nearby species due to growth factors.

Capnophile

An organism that requires increased carbon dioxide for growth.

Halophile

An organism that requires high osmotic pressure (salt) for growth.

Osmotolerant

Organism tolerant of high solute concentrations but not requiring them.

Barophile

Organism that thrives under high hydrostatic pressure.

Psychrophile

Microorganism that grows best at cold temperatures (0–15°C).

Mesophile

Microorganism that grows best at moderate temperatures (~20–40°C).

Thermophile

Microorganism that grows best at high temperatures (>45°C).

Acidophile

Organism that grows best at low pH (acidic conditions).

Neutrophile

Organism with neutral pH optimum (around pH 6.5–7.5).

Alkaliphile

Organism that grows best at high pH (alkaline conditions).

Aerobic

An organism that requires oxygen for growth.

Obligate aerobe

Organism that absolutely requires oxygen as the terminal electron acceptor.

Microaerophile

Organism that requires small amounts of oxygen (2–10%).

Facultative anaerobe

Organism that grows with or without oxygen; often better with oxygen.

Obligate anaerobe

Organism that cannot tolerate oxygen and grows via fermentation or anaerobic respiration.

Aerotolerant

Organism that does not use oxygen for growth but can tolerate it.

Endospore

A tough, dormant, non-reproductive structure formed by some bacteria to survive adverse conditions.

Sporulation

Process of spore formation in response to stress.

Germination

Return of a dormant spore to vegetative growth when conditions improve.

Spore-forming bacteria

Bacteria capable of producing endospores (e.g., Bacillus, Clostridium).

Binary fission

Asexual bacterial cell division producing two genetically identical daughter cells.

Growth curve

Pattern of population growth over time with lag, log, stationary, and death phases.

Lag phase

Adaptation period with growth in size but no division.

Log phase

Exponential growth; rapid population increase.

Stationary phase

Nutrients depleted; growth rate equals death rate.

Death phase

More cells die than are produced; population declines.

Generation time

Time required for a population to double in number.

Turbidity

Cloudiness of a culture, used as a proxy for cell density.

CFU

Colony-forming unit; unit used to estimate viable cell numbers.

MPN

Most probable number; statistical estimate of viable microorganisms.

Macronutrient

Inorganic nutrients required in large amounts for growth (e.g., C, N, O, H, P, S).

Micronutrient

Trace elements required in small amounts for enzyme function (e.g., Mn, Zn, Ni).

Essential nutrient

A nutrient that must be provided for growth; includes macronutrients and micronutrients.

Inorganic nutrient

Nutrient containing atoms other than carbon-hydrogen; includes metals, gases, and minerals.

Organic nutrient

Nutrient containing carbon and hydrogen, typically produced by living organisms.

Autotroph

Organism that uses CO2 as its carbon source.

Heterotroph

Organism that uses organic compounds as a carbon source.

Chemotroph

Organism that gains energy from chemical compounds (not light).

Phototroph

Organism that gains energy from light via photosynthesis.

Lithotroph

Organism that gains energy from inorganic chemical compounds.

Organotroph

Organism that gains energy from organic chemical compounds.

Endospore core/Cortex/Spore coat

Structural components of an endospore: core contains DNA and cytoplasm; cortex is thick peptidoglycan; coat is a protective protein layer.

Calcium dipicolinate (Ca-DPA)

Compund in endospores helping heat resistance and DNA protection.

NAD (V factor)

Growth factor (V factor) required by Haemophilus influenzae; satellite growth around S. aureus due to V factor.

Blood agar

Enriched medium used to grow fastidious organisms and visualize hemolysis.

MacConkey agar

Selective and differential medium for Gram-negative bacteria; differentiates lactose fermenters.

Hemolysis

Destruction of red blood cells on blood agar; patterns include alpha, beta, gamma.

Satellite growth

Growth of one organism around another due to shared growth factors (e.g., NAD from S. aureus enabling H. influenzae growth).

Endospore formation environment

Sporulation is triggered by environmental stress leading to dormant spores.

Endospore germination

Activation and return to vegetative growth when conditions become favorable.

Capsule vs glycocalyx

Glycocalyx is a gelatinous layer; capsule is a distinct protective layer; both aid attachment and immune evasion.