282 ■ CHAPTER 15 Bacteria and Archaea
THE QUESTIONS
The Basics
(^1) Prokaryotes include
(a) archaeans.
(b) bacteria.
(c) fungi.
(d) both a and b
(e) both b and c
(^2) Some prokaryotes can
(a) break down chemicals for energy.
(b) use sunlight for energy.
(c) create their own energy.
(d) harvest energy from other organisms.
(e) all of the above
(^3) Prokaryotes are extremely abundant because
(a) they can survive in a narrow range of environments.
(b) they have a single loop of DNA.
(c) they reproduce very rapidly.
(d) they are able to form biofilms.
(e) all of the above
(^4) Quorum sensing
(a) is the transfer of plasmid DNA from one bacterium to another.
(b) enables bacteria to form biofilms.
(c) is the formation of thick-walled dormant structures, called
spores, under conditions unfavorable for growth.
(d) enables bacteria to switch from cellular respiration to
fermentation when they sense that oxygen levels are low.
(^5) Select the correct terms:
Of the two types of prokaryotes, (Archaea / Bacteria) are more
closely related to eukaryotes. The domain (Archaea / Bacteria)
● (^) Prokaryotes exhibit unmatched
diversity in methods of getting
and using nutrients and energy.
Autotrophs (producers) make
their own food, whereas
heterotrophs (consumers)
obtain food from other
sources. Chemoautotrophs
and chemoheterotrophs
use inorganic chemicals
as their energy source;
photoautotrophs and
photoheterotrophs use sunlight.
● (^) Prokaryotes perform key
tasks in ecosystems,
including photosynthesis,
nitrogen fixation (providing
nitrogen to plants),
and nutrient cycling
(decomposing dead organic
matter).
● (^) Although prokaryotes are
useful to humanity in many
ways, some cause deadly
diseases.
contains some species that are pathogens. (Prokaryotes /
Eukaryotes) have smaller, less complex cells and are able to
reproduce at a more rapid rate. Some (prokaryotes / eukaryotes)
are multicellular.
Challenge Yourself
(^6) Which of the following can prokaryotes not do?
(a) communicate with each other about environmental conditions
(b) reproduce sexually
(c) live in extreme environments, including high salt, high
temperature, and high atmospheric pressure
(d) share DNA with other prokaryotes
(e) double in population size two or more times an hour
(^7) Which of the following descriptions is true only of prokaryotes?
(a) They reproduce through binary fission.
(b) Their genetic material is DNA.
(c) They are unicellular.
(d) They contain organelles within the cell.
(e) none of the above
(^8) Place the following steps of the belly button research
described in this chapter in the correct order by numbering
them from 1 to 5.
a. An observation was made that belly button bacteria
seemed to differ across individuals.
b. The DNA was sequenced.
c. DNA was isolated from the samples.
d. Volunteers had their navels swabbed to collect bacterial
samples.
e. The bacterial samples were grown in petri dishes.
Tr y Something New
(^9) Which of the following is citizen science?
(a) reporting when the first hummingbirds arrive at your feeders in
the spring
(b) completing a Facebook quiz on your horoscope
(c) filling out your medical history at the doctor’s office
(d) all of the above
(e) none of the above
(^10) There are more genera of bacteria and archaeans in the world
than of eukaryotes, and more individuals. However, the total mass
of prokaryotes is thought to be approximately equal to that of
eukaryotes. How can this be?
(^11) Why are prokaryotes able to replicate so much more quickly
than eukaryotes? (Hint: What cellular components must be
copied before a cell splits in two?) Why is this difference in
replication rate an important part of our vulnerability to
bacterial pathogens?