BIOL 438 Final Review Questions with Correct Answers Latest Update 2026/2027
Foods can be spoiled by both intrinsic and extrinsic factors. Extrinsic factors can include things
such as ________. - Answers storage temperature
Extrinsic Factors: - Answers storage temperature, humidity, packaging
Intrinsic Factors: - Answers amount of carbohydrates, presence of a rind, oxidation-reduction
potential, water activity
Canned food available for sale at grocery stores have been subjected to a commercial canning
process. If you bought a can of peas from the local grocery store and found the peas to be
spoiled, it could explained by ______. (Check all that apply.) - Answers underprocessing during
canning, spoilage before canning, and the entrance of contaminated water through the can
seams during cooling
Which of the following statements is false regarding the control of microbial growth by altering
the availability of water? - Answers Foods with a high sugar content such as honey, jams and
jellies, and syrup, have a high aw value, which eliminates the growth of microbes.
True or False: When food supplies, such as beef and pork, are gamma irradiated to kill
pathogenic organisms, the food becomes temporarily radioactive. There is no harm to humans
because the effects have worn off by the time the meat reaches grocery store shelves. -
Answers False
A 2018 outbreak at a popular Ohio fast-casual chain restaurant left over 600 people sick. The
CDC confirmed the presence of a toxin from Clostridium perfringens in the stool samples of
affected individuals. What symptoms would the individuals have suffered? - Answers Cramps
and diarrhea within a day and lasting for 24 hours
Evaluate the statements below and choose those that are correct regarding control of microbes
by regulating the availability of water: - Answers High sugar content in food lowers the aw and
dehydrates nonosmophilic microbes
Nonosmophiles in a hypertonic environment are dehydrated, which limits food spoilage
Osmophiles can withstand the effects of low aw values and may still spoil foods like jams.
Primary metabolites made using industrial fermentation consist of compounds related to the
synthesis of microbial cells during the _______ stage of growth. - Answers exponential
Select all those qualities that are considered desirable in a biofuel. - Answers Easily mixed with
gasoline or used instead of gasoline
, Easy to store and ship
High energy density
Its production does not impact the food supply
Its production and distribution is carbon neutral
Choose the important factors that influence the biodegradation or bioremediation of a particular
environmental contaminant. - Answers The structure and stereochemistry of the compound
The presence or absence of organisms capable of breaking down the compound
The level of oxygen in the environment where the contaminant is present
The chirality or handedness of the compound
One type of bioremediation process promotes the growth of natural microbial populations that
can degrade a given contaminant by adding ________ to the contaminated site. - Answers
nutrients
An example of this bioremediation strategy includes adding Burkholderia (Pseudomonas)
cepacia to 2,4,5-T contaminated soil in order to remove this chemical from the soil (has been
shown successful in laboratory studies). - Answers bioaugmentation
Which of the following lists the reactions that must occur in an anaerobic digester in the correct
sequence? - Answers Fermentation, acetogenesis, methanogenesis
Evaluate the statements below and choose those that correctly apply to the use of endogenous
microbes in bioremediation processes. - Answers Existing microbial activity is often limited by
nutrients or physical conditions
The addition of nitrogen and phosphorus fertilizers increases availability of limiting nutrients
Foods can be spoiled by both intrinsic and extrinsic factors. Extrinsic factors can include things
such as ________. - Answers storage temperature
Extrinsic Factors: - Answers storage temperature, humidity, packaging
Intrinsic Factors: - Answers amount of carbohydrates, presence of a rind, oxidation-reduction
potential, water activity
Canned food available for sale at grocery stores have been subjected to a commercial canning
process. If you bought a can of peas from the local grocery store and found the peas to be
spoiled, it could explained by ______. (Check all that apply.) - Answers underprocessing during
canning, spoilage before canning, and the entrance of contaminated water through the can
seams during cooling
Which of the following statements is false regarding the control of microbial growth by altering
the availability of water? - Answers Foods with a high sugar content such as honey, jams and
jellies, and syrup, have a high aw value, which eliminates the growth of microbes.
True or False: When food supplies, such as beef and pork, are gamma irradiated to kill
pathogenic organisms, the food becomes temporarily radioactive. There is no harm to humans
because the effects have worn off by the time the meat reaches grocery store shelves. -
Answers False
A 2018 outbreak at a popular Ohio fast-casual chain restaurant left over 600 people sick. The
CDC confirmed the presence of a toxin from Clostridium perfringens in the stool samples of
affected individuals. What symptoms would the individuals have suffered? - Answers Cramps
and diarrhea within a day and lasting for 24 hours
Evaluate the statements below and choose those that are correct regarding control of microbes
by regulating the availability of water: - Answers High sugar content in food lowers the aw and
dehydrates nonosmophilic microbes
Nonosmophiles in a hypertonic environment are dehydrated, which limits food spoilage
Osmophiles can withstand the effects of low aw values and may still spoil foods like jams.
Primary metabolites made using industrial fermentation consist of compounds related to the
synthesis of microbial cells during the _______ stage of growth. - Answers exponential
Select all those qualities that are considered desirable in a biofuel. - Answers Easily mixed with
gasoline or used instead of gasoline
, Easy to store and ship
High energy density
Its production does not impact the food supply
Its production and distribution is carbon neutral
Choose the important factors that influence the biodegradation or bioremediation of a particular
environmental contaminant. - Answers The structure and stereochemistry of the compound
The presence or absence of organisms capable of breaking down the compound
The level of oxygen in the environment where the contaminant is present
The chirality or handedness of the compound
One type of bioremediation process promotes the growth of natural microbial populations that
can degrade a given contaminant by adding ________ to the contaminated site. - Answers
nutrients
An example of this bioremediation strategy includes adding Burkholderia (Pseudomonas)
cepacia to 2,4,5-T contaminated soil in order to remove this chemical from the soil (has been
shown successful in laboratory studies). - Answers bioaugmentation
Which of the following lists the reactions that must occur in an anaerobic digester in the correct
sequence? - Answers Fermentation, acetogenesis, methanogenesis
Evaluate the statements below and choose those that correctly apply to the use of endogenous
microbes in bioremediation processes. - Answers Existing microbial activity is often limited by
nutrients or physical conditions
The addition of nitrogen and phosphorus fertilizers increases availability of limiting nutrients
