Nester's Microbiology Chapter 4
biofilm - ANSPolymer-encased community of microorganims
Chemically defined medium - ANSA culture medium composed of exact quantities of pure
chemicals; generally used only for specific experiments when nutrients must be precisely
controlled
complex medium - ANSa culture medium that contains protein digests, extracts, or other
ingredients that vary in their chemical composition
differential medium - ANSa culture medium with an ingredient that certain microbes change in a
recognizable way; used to differentiate microbes based on their metabolic traits
exponential (log) phase - ANSStage in the growth curve during which cells divide at a constant
rate; generation time is measured during this period of active multiplication
facultative anaerobe - ANSorganism grows best if O2 is available, but can also grow without it
Generation time - ANSthe time it takes for a population to double in number
obligate aerobe - ANSorganism that requires O2
obligate anaerobe - ANSorganism that cannot multiply, and is often killed in the presence of O2
plate count - ANSmethod to measure the concentration of viable cells by counting the number of
colonies that develop from a sample added to an agar plate
pure culture - ANSa population descended from a single cell
selective medium - ANSa culture medium with an ingredient that inhibits the growth of microbes
other than the one being sought
binary fission - ANSa process in which a cell increases in size and then divides
aseptic technique - ANSa set of procedures that minimize the chance of other organisms being
accidentally introduced
colony - ANSa distinct mass of cells
agar - ANSa polysaccharide extracted from marine algae, used to solidify culture medium
biofilm - ANSPolymer-encased community of microorganims
Chemically defined medium - ANSA culture medium composed of exact quantities of pure
chemicals; generally used only for specific experiments when nutrients must be precisely
controlled
complex medium - ANSa culture medium that contains protein digests, extracts, or other
ingredients that vary in their chemical composition
differential medium - ANSa culture medium with an ingredient that certain microbes change in a
recognizable way; used to differentiate microbes based on their metabolic traits
exponential (log) phase - ANSStage in the growth curve during which cells divide at a constant
rate; generation time is measured during this period of active multiplication
facultative anaerobe - ANSorganism grows best if O2 is available, but can also grow without it
Generation time - ANSthe time it takes for a population to double in number
obligate aerobe - ANSorganism that requires O2
obligate anaerobe - ANSorganism that cannot multiply, and is often killed in the presence of O2
plate count - ANSmethod to measure the concentration of viable cells by counting the number of
colonies that develop from a sample added to an agar plate
pure culture - ANSa population descended from a single cell
selective medium - ANSa culture medium with an ingredient that inhibits the growth of microbes
other than the one being sought
binary fission - ANSa process in which a cell increases in size and then divides
aseptic technique - ANSa set of procedures that minimize the chance of other organisms being
accidentally introduced
colony - ANSa distinct mass of cells
agar - ANSa polysaccharide extracted from marine algae, used to solidify culture medium
