CH. 9 Microbial growth
What is the goal number of CFUs on a spread plate if a serial dilution is done correctly?
30-300 per plate
Which of the following best describes the cell membranes of microbes that thrive at low temperatures?
They have relatively high amounts of unsaturated fatty acids.
Match each type of organism with the best description of its oxygen requirements. Facultative anaerobe
an organism that can grow without oxygen, but grows best with it
Match each type of organism with the best description of its oxygen requirements. Aerotolerant anaerobes
an organism that grows equally well with or w/o oxygen
Match each type of organism with the best description of its oxygen requirements. Microearophile
an organism that requires a low level of oxygen (less than atmospheric normal)
Match each type of organism with the best description of its oxygen requirements. Obligate anaerobe
an organism that requires an oxygen-free environment
Match each type of organism with the best description of its oxygen requirements. Obligate aerobe
an organism that requires oxygen to survive
Which of the following is not a reactive oxygen species?
atmospheric oxygen
Match each type of microbe with the best description by optimal temperature range for growth. Psychrotroph
b/w ~4-25C
Bacteria most commonly reproduce using which of the following methods?
binary fission
A candle jar is often used to grow which type of bacteria?
capnophiles
Which best defines the term "persisters?"
cells with relatively slow metabolic rates that survive longer than others during the death phase and that can cause chronic infections
Which type of system is used to maintain bacteria in a relatively constant environment, allowing them to stay in the log phase of growth?
chemostat
f you grow two species of bacteria on mannitol salt agar to determine which can ferment mannitol, and you know both species can grow on the medium, which type of medium is the agar?
differential
Which of the following is another term for generation time?
doubling time
Which of the following is not an example of an enzyme used to detoxify reactive oxygen species?
permeases
Which of the following is the term for free-living bacteria?
planktonic
Which of the following would be the best choice for distinguishing living and dead bacteria in a cell count?
primary and secondary fluorescent stains
Capnophiles are bacteria that grow best under which of the following conditions?
relatively high CO2 and relatively low oxygen concentrations
The initial cells added to a batch culture are called which of the following?
the inoculum
Which of the following best describes FtsZ?
the protein that assembles the Z ring, which forms a divisome before division by binary fission
Which of the following media is commonly used to determine the oxygen requirements of a bacterial species?`
thioglycolate medium
Which of the following is an indirect method of measuring numbers of bacterial cells?
turbidity measurements
Match each type of microbe with the best description by optimal temperature range for growth. Psychrophile
~0-15C
Match each type of microbe with the best description by optimal temperature range for growth. Mesophile
~20-40C
Match each type of microbe with the best description by optimal temperature range for growth. Hyperthermophile
~80-110C
Match each type of microbe with the best example. Microaerophile
Campylobacter pylori
Match each type of microbe with the best example. Obligate anaearobe
Clostridium difficile
Match each type of microbe with the best example. Facultative anaerobe
Staphylococcus
Match each type of microbe with the best example. Aerotolerant
Streptococcus
Which of the following best describes why extracellular polymeric substances are important?
They are components of a biofilm secreted by the microbes present.
Which best describes bacterial growth during the log phase of the growth curve?
exponential
Quorum sensing always occurs between members of the same species.
false
Which of the following is the correct order of phases of growth in the growth curve of a batch culture?
lag phase-->log phase-->stationary phase-->death/decline phase
Human pathogens are generally which type of microbe?
mesophiles
