Cultivation of Microorganisms and Environmental Factors

This set of flashcards covers key terms and definitions related to the cultivation of microorganisms, their growth factors, and methods for microbial control.

Cultivation of Microorganisms

The process by which microorganisms are grown artificially in the laboratory using appropriate culture medium under favorable environmental conditions.

Nutrients

Essential substances required for the growth of microorganisms; categorized into macronutrients (needed in large quantities) and micronutrients (trace elements).

Autotrophs

Microorganisms that depend solely on inorganic carbon (CO2) for their carbon needs.

Heterotrophs

Organisms whose carbon sources are obtained from organic molecules.

Aerobes

Organisms that grow well in the presence of oxygen.

Anaerobes

Organisms that are unable to grow in the presence of oxygen.

Facultative anaerobes

Organisms that can grow in both the presence and absence of oxygen.

Psychrophiles

Microorganisms that grow optimally at temperatures of 15°C and below.

Mesophiles

Microorganisms that grow at moderate temperatures, between 20°C and 40°C.

Thermophiles

Microorganisms that grow optimally at temperatures greater than 45°C.

pH

A scale used to specify the acidity or basicity of an aqueous solution; most pathogenic bacteria prefer a pH of 7.2-7.6.

Capnophiles

Microbes that grow best at higher levels of CO2 than typically present in the atmosphere.

Binary fission

A method of asexual reproduction in which a parent bacterium divides into two identical daughter cells.

Lag phase

The initial phase of bacterial growth where cells adapt to their new environment.

Log phase

The phase in bacterial growth characterized by rapid cell division and growth.

Stationary phase

The phase where the growth rate slows and stabilizes as nutrients deplete and waste accumulates.

Death phase

The phase in bacterial growth where the rate of cell death exceeds the rate of cell division.

Sterilization

The process of completely destroying all viable microorganisms from an object or habitat.

Disinfection

The process of eliminating or reducing microorganisms on inanimate objects.

Biocide

An antimicrobial agent that kills all living microorganisms including spores.

Biostat

An agent that prevents the growth of microorganisms without necessarily killing them.

Antisepsis

The prevention of infection by destroying or inhibiting microbial growth on tissues.

Moist heat

A physical method for microbial control involving steam or boiling water.

Ionizing radiation

A type of radiation used for sterilization that damages microbial DNA.

Non-ionizing radiation

A type of radiation that sterilizes surfaces but does not penetrate materials effectively.

Chemical agents

Substances used in disinfection and antisepsis that target and reduce microbial populations.