27.4 Prokaryotes have radiated into a diverse set of lineages

Question 1

55) Mitochondria are thought to be the descendants of certain alpha-proteobacteria. They are,
however, no longer able to lead independent lives because most genes originally present on
their chromosome have moved to the nuclear genome. Which phenomenon accounts for
the movement of these genes?
A) horizontal gene transfer
B) binary fission
C) alternative gene splicing
D) meiosis
E) plasmolysis

Answer 1

A) horizontal gene transfer

Question 2

56) Carl Woese and collaborators identified two major branches of prokaryotic evolution. What
was the basis for dividing prokaryotes into two domains?
A) microscopic examination of staining characteristics of the cell wall
B) metabolic characteristics such as the production of methane gas
C) metabolic characteristics such as chemoautotrophy and photosynthesis
D) genetic characteristics such as ribosomal RNA sequences
E) ecological characteristics such as the ability to survive in extreme environments

Answer 2

D) genetic characteristics such as ribosomal RNA sequences

Question 3

57) Which statement about the domain Archaea is false?
A) Genetic prospecting has recently revealed the existence of many previously unknown archean species.
B) Some archaeans can reduce CO2 to methane.
C) The genomes of archaeans are unique, containing no genes that originated within bacteria.
D) Some archaeans can inhabit solutions that are nearly 30% salt.
E) Some archaeans are adapted to waters with temperatures above the boiling point.

Answer 3

C) The genomes of archaeans are unique, containing no genes that originated within bacteria.

Question 4

58) If archaeans are more closely related to eukaryotes than to bacteria, then which of the
following is a reasonable prediction?
A) Archaean DNA should have no introns.
B) Archaean chromosomes should have no protein bonded to them.
C) Archaean DNA should be single-stranded.
D) Archaean ribosomes should be larger than typical prokaryotic ribosomes.
E) Archaeans should lack cell walls.

Answer 4

D) Archaean ribosomes should be larger than typical prokaryotic ribosomes.

Question 5

59) Which of the following traits do archaeans and bacteria share?
1. composition of the cell wall
2. presence of plasma membrane
3. lack of a nuclear envelope
4. identical rRNA sequences
A) 1 only
B) 3 only
C) 1 and 3
D) 2 and 3
E) 2 and 4

Answer 5

D) 2 and 3

Question 6

60) Assuming that each of these possesses a cell wall, which prokaryotes should be expected to
be most strongly resistant to plasmolysis in hypertonic environments?
A) extreme halophiles
B) extreme thermophiles
C) methanogens
D) cyanobacteria
E) nitrogen-fixing bacteria that live in root nodules

Answer 6

A) extreme halophiles

Question 7

62) The thermoacidophile, Sulfolobus acidocaldarius lacks peptidoglycan. What is likely to be
true of this species?
1. It is a bacterium.
2. It is an archaean.
3. The optimal pH of its enzymes will lie above pH 7.
4. The optimal pH of its enzymes will lie below pH 7.
5. It could inhabit certain hydrothermal springs.
6. It could inhabit alkaline hot springs.
A) 1, 3, and 6
B) 2, 4, and 6
C) 2, 4, and 5
D) 1, 3, and 5
E) 1, 4, and 5

Answer 7

C) 2, 4, and 5

Question 8

63) A fish that had been salt-cured subsequently develops a reddish color. You suspect that the
fish has been contaminated by the extreme halophile, Halobacterium. Which of these
features of cells removed from the surface of the fish, if confirmed, would support your
suspicion?
1. the presence of the same photosynthetic pigments found in cyanobacteria
2. cell walls that lack peptidoglycan
3. cells that are isotonic to conditions on the surface of the fish
4. its cells contain bacteriorhodopsin
5. the presence of very large numbers of ion pumps in its plasma membrane
A) 2 and 5
B) 3 and 4
C) 1, 4, and 5
D) 3, 4, and 5
E) 2, 3, 4, and 5

Answer 8

E) 2, 3, 4, and 5