MGCCC Micro Exam 4 Dr. Ryan 2026
Exam Questions And Answers Already
Graded A+
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
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
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
a clinical sample labeled as sputum was collected from - CORRECT ANSWER-the
lungs
an acidophile thrives under conditions of low - CORRECT ANSWER-pH
the method of obtaining isolated cultures that utilizes surface area to dilute specimens is
called - CORRECT ANSWER-the streak plate technique
which of the following is NOT a direct method for measuring the number of microbes in
a sample? - CORRECT ANSWER-turbidity
cells rapidly growing and dividing during the ___ of growth - CORRECT ANSWER-log
phase
metabolic activity is at maximum level in the ___ of growth - CORRECT ANSWER-log
phase
a petroff- hauser counting chamber is - CORRECT ANSWER-a glass slide containing
an etched grid for counting microbes directly using a microscope
Exam Questions And Answers Already
Graded A+
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
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
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
a clinical sample labeled as sputum was collected from - CORRECT ANSWER-the
lungs
an acidophile thrives under conditions of low - CORRECT ANSWER-pH
the method of obtaining isolated cultures that utilizes surface area to dilute specimens is
called - CORRECT ANSWER-the streak plate technique
which of the following is NOT a direct method for measuring the number of microbes in
a sample? - CORRECT ANSWER-turbidity
cells rapidly growing and dividing during the ___ of growth - CORRECT ANSWER-log
phase
metabolic activity is at maximum level in the ___ of growth - CORRECT ANSWER-log
phase
a petroff- hauser counting chamber is - CORRECT ANSWER-a glass slide containing
an etched grid for counting microbes directly using a microscope
