CAMPBELL BIOLOGY CHAPTERS 27-31 EXAM QUESTIONS WITH VERIFIED SOLUTIONS
GRADED A+
anaerobic respiration - Answers A catabolic pathway in which inorganic molecules other than
oxygen accept electrons at the "downhill" end of electron transport chains.
biofilm - Answers A surface-coating colony of one or more species of prokaryotes that engage
in metabolic cooperation.
bioremediation - Answers The use of organisms to detoxify and restore polluted and degraded
ecosystems.
capsule - Answers (1) In many prokaryotes, a dense and well-defined layer of polysaccharide or
protein that surrounds the cell wall and is sticky, protecting the cell and enabling it to adhere to
substrates or other cells. (2) The sporangium of a bryophyte (moss, liverwort, or hornwort).
chemoautotroph - Answers An organism that obtains energy by oxidizing inorganic substances
and needs only carbon dioxide as a carbon source.
chemoheterotroph - Answers An organism that requires organic molecules for both energy and
carbon.
commensalism - Answers A +/0 ecological interaction in which one organism benefits but the
other is neither helped nor harmed.
conjugation - Answers (1) In prokaryotes, the direct transfer of DNA between two cells that are
temporarily joined. When the two cells are members of different species, conjugation results in
horizontal gene transfer. (2) In ciliates, a sexual process in which two cells exchange haploid
micronuclei but do not reproduce.
decomposer - Answers An organism that absorbs nutrients from nonliving organic material
such as corpses, fallen plant material, and the wastes of living organisms and converts them to
inorganic forms; a detritivore.
endospore - Answers A thick-coated, resistant cell produced by some bacterial cells when they
are exposed to harsh conditions.
endotoxin - Answers A toxic component of the outer membrane of certain gram-negative
bacteria that is released only when the bacteria die.
exotoxin - Answers A toxic protein that is secreted by a prokaryote or other pathogen and that
produces specific symptoms, even if the pathogen is no longer present.
extreme halophile - Answers An organism that lives in a highly saline environment, such as the
Great Salt Lake or the Dead Sea.
extreme thermophile - Answers An organism that thrives in hot environments (often 60−80°C or
, hotter).
extremophile - Answers An organism that lives in environmental conditions so extreme that few
other species can survive there. They include extreme halophiles ("salt lovers") and extreme
thermophiles ("heat lovers").
facultative anaerobe - Answers An organism that makes ATP by aerobic respiration if oxygen is
present but that switches to anaerobic respiration or fermentation if oxygen is not present.
F factor - Answers In bacteria, the DNA segment that confers the ability to form pili for
conjugation and associated functions required for the transfer of DNA from donor to recipient. It
may exist as a plasmid or be integrated into the bacterial chromosome.
fimbria (plural, fimbriae) - Answers A short, hairlike appendage of a prokaryotic cell that helps it
adhere to the substrate or to other cells.
F plasmid - Answers The plasmid form of the F factor.
gram-negative - Answers Describing the group of bacteria that have a cell wall that is
structurally more complex and contains less peptidoglycan than the cell wall of gram-positive
bacteria. Bacteria that fall under this are often more toxic than gram-positive bacteria.
gram-positive - Answers Describing the group of bacteria that have a cell wall that is structurally
less complex and contains more peptidoglycan than the cell wall of gram-negative bacteria.
Bacteria that fall under this are usually less toxic than gram-negative bacteria.
Gram stain - Answers A staining method that distinguishes between two different kinds of
bacterial cell walls; may be used to help determine medical response to an infection.
heterocyst - Answers A specialized cell that engages in nitrogen fixation in some filamentous
cyanobacteria; also called a heterocyte.
host - Answers The larger participant in a symbiotic relationship, often providing a home and
food source for the smaller symbiont.
mean - Answers The sum of all data points in a data set divided by the number of data points.
methanogen - Answers An organism that produces methane as a waste product of the way it
obtains energy. All known organisms in this category are in domain Archaea.
mutualism - Answers A +/+ ecological interaction that benefits each of the interacting species.
nitrogen fixation - Answers The conversion of atmospheric nitrogen (N2) to ammonia (NH3). It
is carried out by certain prokaryotes, some of which have mutualistic relationships with plants.
nucleoid - Answers A non-membrane-enclosed region in a prokaryotic cell where its
chromosome is located.
GRADED A+
anaerobic respiration - Answers A catabolic pathway in which inorganic molecules other than
oxygen accept electrons at the "downhill" end of electron transport chains.
biofilm - Answers A surface-coating colony of one or more species of prokaryotes that engage
in metabolic cooperation.
bioremediation - Answers The use of organisms to detoxify and restore polluted and degraded
ecosystems.
capsule - Answers (1) In many prokaryotes, a dense and well-defined layer of polysaccharide or
protein that surrounds the cell wall and is sticky, protecting the cell and enabling it to adhere to
substrates or other cells. (2) The sporangium of a bryophyte (moss, liverwort, or hornwort).
chemoautotroph - Answers An organism that obtains energy by oxidizing inorganic substances
and needs only carbon dioxide as a carbon source.
chemoheterotroph - Answers An organism that requires organic molecules for both energy and
carbon.
commensalism - Answers A +/0 ecological interaction in which one organism benefits but the
other is neither helped nor harmed.
conjugation - Answers (1) In prokaryotes, the direct transfer of DNA between two cells that are
temporarily joined. When the two cells are members of different species, conjugation results in
horizontal gene transfer. (2) In ciliates, a sexual process in which two cells exchange haploid
micronuclei but do not reproduce.
decomposer - Answers An organism that absorbs nutrients from nonliving organic material
such as corpses, fallen plant material, and the wastes of living organisms and converts them to
inorganic forms; a detritivore.
endospore - Answers A thick-coated, resistant cell produced by some bacterial cells when they
are exposed to harsh conditions.
endotoxin - Answers A toxic component of the outer membrane of certain gram-negative
bacteria that is released only when the bacteria die.
exotoxin - Answers A toxic protein that is secreted by a prokaryote or other pathogen and that
produces specific symptoms, even if the pathogen is no longer present.
extreme halophile - Answers An organism that lives in a highly saline environment, such as the
Great Salt Lake or the Dead Sea.
extreme thermophile - Answers An organism that thrives in hot environments (often 60−80°C or
, hotter).
extremophile - Answers An organism that lives in environmental conditions so extreme that few
other species can survive there. They include extreme halophiles ("salt lovers") and extreme
thermophiles ("heat lovers").
facultative anaerobe - Answers An organism that makes ATP by aerobic respiration if oxygen is
present but that switches to anaerobic respiration or fermentation if oxygen is not present.
F factor - Answers In bacteria, the DNA segment that confers the ability to form pili for
conjugation and associated functions required for the transfer of DNA from donor to recipient. It
may exist as a plasmid or be integrated into the bacterial chromosome.
fimbria (plural, fimbriae) - Answers A short, hairlike appendage of a prokaryotic cell that helps it
adhere to the substrate or to other cells.
F plasmid - Answers The plasmid form of the F factor.
gram-negative - Answers Describing the group of bacteria that have a cell wall that is
structurally more complex and contains less peptidoglycan than the cell wall of gram-positive
bacteria. Bacteria that fall under this are often more toxic than gram-positive bacteria.
gram-positive - Answers Describing the group of bacteria that have a cell wall that is structurally
less complex and contains more peptidoglycan than the cell wall of gram-negative bacteria.
Bacteria that fall under this are usually less toxic than gram-negative bacteria.
Gram stain - Answers A staining method that distinguishes between two different kinds of
bacterial cell walls; may be used to help determine medical response to an infection.
heterocyst - Answers A specialized cell that engages in nitrogen fixation in some filamentous
cyanobacteria; also called a heterocyte.
host - Answers The larger participant in a symbiotic relationship, often providing a home and
food source for the smaller symbiont.
mean - Answers The sum of all data points in a data set divided by the number of data points.
methanogen - Answers An organism that produces methane as a waste product of the way it
obtains energy. All known organisms in this category are in domain Archaea.
mutualism - Answers A +/+ ecological interaction that benefits each of the interacting species.
nitrogen fixation - Answers The conversion of atmospheric nitrogen (N2) to ammonia (NH3). It
is carried out by certain prokaryotes, some of which have mutualistic relationships with plants.
nucleoid - Answers A non-membrane-enclosed region in a prokaryotic cell where its
chromosome is located.
