Micro Exam 4 - MGCCC Dr. Ryan
questions with complete solutions A+
organisms that require organic sources of carbon and energy are called - correct answer
✔✔chemoheterotrophs
the ___ growth temperature is the temperature at which an organism exhibits the highest growth rate -
correct answer ✔✔optimum
a growth curve plots the ___ of organisms in a growing population over time - correct answer
✔✔number
T or F: in spectrophotometry, 40% light transmission is the same thing as 60% absorbance of light -
correct answer ✔✔TRUE
T or F: obligate anaerobes have enzymes such as superoxide dismutase to protect them from damaging
effects of oxygen - correct answer ✔✔FALSE
T or F: a selective medium can be formulated either by including inhibitory chemical substances or by
leaving out a single crucial nutrient - correct answer ✔✔TRUE
Metabolic activity is at a max level in the ___ of growth - correct answer ✔✔log phase
a microbiologist inoculates a growth medium with 100 bacterial cells/ml. If the generation time of the
species is 1 hour, and there is no lag phase, how long will it be before the culture contains more than
10,000 cells/ml? - correct answer ✔✔7 hours
a cell that uses an organic carbon source and obtains energy from light would be called a - correct
answer ✔✔photoheterotroph
, joan wants to discover a microbe capable of degrading an environmental contaminant. Which of the
following refers to the process she should use? - correct answer ✔✔enrichment culture
a microorganism found living under conditions of high ___ is a barophile - correct answer ✔✔hydrostatic
pressure
all of the following ingredients might be found in complex media EXCEPT - correct answer ✔✔hydrogen
peroxide
the term barophile refers to which of the following growth requirements? - correct answer
✔✔hydrostatic pressure
a clinical sample labeled as sputum was collected from - correct answer ✔✔the lungs
an acidophile thrives under conditions of low - correct answer ✔✔pH
which of the following organisms would be most likely to contaminate a jar of pickles? - correct answer
✔✔an acidophile
a specimen of urine is determined to contain 30 bacterial cells per microliter. How many cells would be
present in a milliliter? - correct answer ✔✔30,000
an epidemiologist is investigating a new disease and observes what appear to be bacteria inside tissue
cells in clinical samples from victims. The scientists wants to try to isolate the bacteria in the lab. What
culture conditions are most likely to be successful? - correct answer ✔✔inoculation of cell cultures
a gelling agent derived from algae that is useful for creating solid growth media is called - correct answer
✔✔agar
the conversion of nitrogen gas to ammonia is called nitrogen - correct answer ✔✔fixation
T or F: nitrogen fixation is a process that occurs in all bacteria - correct answer ✔✔FALSE
questions with complete solutions A+
organisms that require organic sources of carbon and energy are called - correct answer
✔✔chemoheterotrophs
the ___ growth temperature is the temperature at which an organism exhibits the highest growth rate -
correct answer ✔✔optimum
a growth curve plots the ___ of organisms in a growing population over time - correct answer
✔✔number
T or F: in spectrophotometry, 40% light transmission is the same thing as 60% absorbance of light -
correct answer ✔✔TRUE
T or F: obligate anaerobes have enzymes such as superoxide dismutase to protect them from damaging
effects of oxygen - correct answer ✔✔FALSE
T or F: a selective medium can be formulated either by including inhibitory chemical substances or by
leaving out a single crucial nutrient - correct answer ✔✔TRUE
Metabolic activity is at a max level in the ___ of growth - correct answer ✔✔log phase
a microbiologist inoculates a growth medium with 100 bacterial cells/ml. If the generation time of the
species is 1 hour, and there is no lag phase, how long will it be before the culture contains more than
10,000 cells/ml? - correct answer ✔✔7 hours
a cell that uses an organic carbon source and obtains energy from light would be called a - correct
answer ✔✔photoheterotroph
, joan wants to discover a microbe capable of degrading an environmental contaminant. Which of the
following refers to the process she should use? - correct answer ✔✔enrichment culture
a microorganism found living under conditions of high ___ is a barophile - correct answer ✔✔hydrostatic
pressure
all of the following ingredients might be found in complex media EXCEPT - correct answer ✔✔hydrogen
peroxide
the term barophile refers to which of the following growth requirements? - correct answer
✔✔hydrostatic pressure
a clinical sample labeled as sputum was collected from - correct answer ✔✔the lungs
an acidophile thrives under conditions of low - correct answer ✔✔pH
which of the following organisms would be most likely to contaminate a jar of pickles? - correct answer
✔✔an acidophile
a specimen of urine is determined to contain 30 bacterial cells per microliter. How many cells would be
present in a milliliter? - correct answer ✔✔30,000
an epidemiologist is investigating a new disease and observes what appear to be bacteria inside tissue
cells in clinical samples from victims. The scientists wants to try to isolate the bacteria in the lab. What
culture conditions are most likely to be successful? - correct answer ✔✔inoculation of cell cultures
a gelling agent derived from algae that is useful for creating solid growth media is called - correct answer
✔✔agar
the conversion of nitrogen gas to ammonia is called nitrogen - correct answer ✔✔fixation
T or F: nitrogen fixation is a process that occurs in all bacteria - correct answer ✔✔FALSE
