CHAPTER 6 Flashcards
what two groups of organisms based on source of carbon
autotrophs and heterotrophs
what two groups of organisms based on source of energy
chemotrophs and phototrophs
what two groups of organisms are based on source of electrons
organotrophs and lithotrophs
what are organotrophs
heterotrophs, organic molecules are source of e-
what are lithotrophs
autotrophs, inorganic molecules source of e-
t or f
oxygen is essential for obligate aerobes
true
t or f
oxygen is essential for obligate anaerobes
false; it is deadly
what are 4 toxic forms of oxygen
singlet oxygen
superoxide radicals
peroxide anion
hydroxyl radical
define obligate aerobe
cannot grow w/out oxygen
define facultative anaerobe
prefer utilizing oxygen but can also can grow/survive w/out it
define microaerophile
requires low amount of oxygen. high levels can be lethal
define obligate anaerobe
lacks the enzymes to detoxify oxygen so cannot survive in an oxygen environment
define aerotolerant anaerobes
do not utilize oxygen for metabolism but can survive and grow in its presence
anabolism often ceases due to insufficient _______
nitrogen
what happens in nitrogen fixation
convert atmospheric N2 to NH3 (essential to life on earth)
define trace elements
elements required in small amounts
define trace elements
elements required in small amounts
define fastidious
organisms that need multiple growth factors
what affects the 3D structure of proteins
temperature
define cardinal temperatures
range of temperatures for microbial growth
minimum vs maximum temperature
lowest/highest temp that permits a microbes growth and metabolism
define optimum temperature
promotes the fastest rate of growth and metabolism
define psychrophiles
optimum temp below 15 degrees C; capable of growth @ 0 degrees C
mesophiles optimum temp
optimum temp 20-40 degrees C; most human pathogens
psychrotroph optimum temp
grows below 20 degrees C
thermophiles optimum temp
greater than 45 degrees C; generally range of 50-60 degrees C; found in hot springs
Hyperthermophiles/ extreme thermophiles optimum temp
greater than 80 degrees C
neutrophiles grow best in a narrow range around _____pH
neutral
acidophiles grow best in
acidic habitats
alkalinophiles live in
alkaline soils and water
define hypotonic solutions
have lower solute concentrations; cell will swell in this solution
define hypertonic solutions
have greater solute concentrations; cell will shrivel in this solution
obligate halophiles thrive in
high salt environments
barophiles live under extreme
pressure
what is an antagonistic relationship
one of the members is harmed or killed
what is a synergistic relationship
greater benefits together than alone
what is symbiotic relationship
interdependent on eachother
what is quorum sensing
the regulation of gene expression in response to fluctuations in cell population density
define synthetic media
exact chemical composition is known
define complex media
exact chemical composition is unknown
define selective media
contain substances that favor or inhibit growth of particular microorgansims
define differential media
allows growth of several types of microbes
define anaerobic media
special culture conditions for obligate anaerobes
define transport media
ensure clinical specimens are not contaminated
Refrigeration stores for
short periods of time
deep-freezing stores for
years
lyophilization stores for
decades
what is generation time
time required for a bacterial cell to grow and divide
what is the lag phase of the growth curve
flat period of adjustment, enlargement, little growth
what is the exponential growth phase of the growth curve
a period of maximum growth when cells have adequate nutrients
what is the stationary phase of the growth curve
rate of cell growth = rate of cell death caused by depleted nutrients
what is the death phase of the growth curve
as limiting factors intensify, cells due exponentially
what is a chemostat
used to maintain a microbial population in a particular phase of growth
coulter counter counts cells as they
interrupt an electrical current
flow cytometry detects change in
light transmission as cells pass a detector
what are the indirect methods of counting microbial reproduction
turbidity, metabolic activity, dry weight, genetic methods
