A28fiffAnswers
Q2: From the micrographs here, does it appear that all prokaryotes
have a flagellum?
A2: No.
Q3: Which one of these shapes is most clearly capable of self-
motility? Why?
A3: The comma, or vibrio, because of the flagellum.
Figure 15.8
Q1: Which shape in Figure 15.7 corresponds to the archaeans from
deep-sea thermal vents?
A1: Rod, or bacillus.
Q2: Why are many archaeans referred to as “extremophiles”?
A2: They are found in extreme environments (at extremes of heat,
acidity, and salt level).
Q3: Is there anywhere you think archaeans could not sur vive?
Justify your answer.
A3: Various answers are possible.
Figure 15.9
Q1: How do individual bacteria know that they have a “quorum”?
A1: They detect increasing concentrations of signaling molecules.
Q2: There is a well-known biofilm found in your mouth. What is it?
A2: Dental plaque.
Q3: Under what conditions might bacteria want to coordinate (via
quorum sensing) to increase their reproductive rate?
A3: If environmental conditions are very good, then it makes sense
for the population of bacteria to grow as quickly as possible to take
advantage of those conditions.
Figure 15.10
Q1: What source of energy would you expect a cave-dwelling
prokaryote to use?
A1: It could not rely on light, so it would most likely use chemical
energy.
Q2: In which of these categories would you place the bacteria
responsible for nitrogen fixing? Why?
A2: Chemoautotroph, because they use nitrogen from the
atmosphere and carbon from carbon dioxide.
Q3: In which of these categories do decomposers belong? Explain
your reasoning.
A3: Chemoheterotroph, because they receive both carbon and
energy from dead or dying organisms.
Figure 15.11
Q1: From the prokaryotic structures shown in Figure 15.7,
what shape would you assign to drawing number 8 in van
Leeuwenhoek’s illustration?
A1: The comma, or vibrio, because of the flagellum.
Q2: Which of the large prokaryote drawings has the coccus shape?
A2: 24.
Q3: Do you think all of these “animalcules” drawn by van
Leeuwenhoek are prokaryotes? Why or why not?A3: No. Some have such an elaborate structure that they are most
likely eukaryotes.CHAPTER 16
END-OF-CHAPTER ANSWERS
- a
- d
- c
- d
- Protista, aquatic, autotrophs
- (a) 3, (b) 5, (c) 4, (d) 1, (e) 2
- e
- The kingdom Plantae contains only autotrophs. The kingdom
Fungi contains only heterotrophs. - For each case, answers to the first part of the question will
vary; here’s an example for part (b): Lichens are a symbiotic
relationship between a fungus and intracellular bacteria.
The photosynthetic bacteria produce food for the fungus, and
the fungus provides protection and anchoring for the bacteria.
Answers to the second and third parts of the question are as
follows:
(a) The partners of mycorrhizae are plants (domain Eukarya,
kingdom Plantae) and fungi (domain Eukarya, kingdom
Fungi). The relationship is a mutualism.(b) The partners of a lichen are fungi (domain Eukarya,
kingdom Fungi) and either algae (domain Eukarya, kingdom
Protista) or cyanobacteria (domain Bacteria). The relationship
is a mutualism.(c) The partners in this relationship are hermit crabs and
the (nonliving) shells of various species of snails (both
domain Eukarya, kingdom Animalia). The relationship is
a commensalism.(d) The partners in this relationship include the malaria
protozoan, its insect host, and its vertebrate host (all domain
Eukarya; kingdom Protista for the malaria protozoan,
kingdom Animalia for the two host types). It is a parasitic
relationship.- Gymnosperms and angiosperms produce pollen, which is
able to travel via wind or a pollinator to other individuals of
the same species, thereby enabling sexual reproduction in a
nonaquatic environment. - Possible answers include athlete’s foot, fungal pneumonia, and
yeast infections.