Microbiology Evolving Science 3rd Edition by Slonczewski Foster – Test Bank
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CHAPTER 3: Cell Structure and Function
MULTIPLE CHOICE
1. E.
coli and Sinorhizobium cell-surface
proteins enable colonization of __________ and __________, respectively.
|
a. |
the human intestinal
epithelium; animal skin |
|
b. |
legume plants; the human
intestinal epithelium |
|
c. |
the human intestinal
epithelium; legume plants |
|
d. |
legume plants; animal skin |
|
e. |
cantaloupe; spinach |
ANS: C
DIF: Medium
REF: 3.1
TOP: I.A.iv.a
MSC: Remembering
2. The
capsule polysaccharides form a slippery mucous layer that inhibits:
|
a. |
diffusion |
d. |
lysis |
|
b. |
phagocytosis |
e. |
osmosis |
|
c. |
attachment |
|
|
ANS:
B
DIF:
Easy
REF:
3.1
TOP: I.A.vi.c
MSC: Remembering
3. We
cannot literally see the molecules within a cell, but __________ and __________
analysis generate a remarkably detailed view.
|
a. |
structural; genetic |
d. |
microscopy; subcellular |
|
b. |
microscopy; genetic |
e. |
chemical; genetic |
|
c. |
structural; subcellular |
|
|
ANS:
D
DIF: Medium
REF: 3.1
TOP: I.B
MSC: Remembering
4. __________
stabilize ribosomes during translation.
|
a. |
Polysaccharides |
d. |
Lipids |
|
b. |
Nucleic acids |
e. |
Phospholipids |
|
c. |
Polyamines |
|
|
ANS:
C
DIF: Medium
REF: 3.1
TOP: I.C.i.c
MSC: Remembering
5. Polyamines
are __________ charged when the pH is near neutral.
|
a. |
not |
d. |
super |
|
b. |
negatively |
e. |
randomly |
|
c. |
positively |
|
|
ANS:
C
DIF: Medium
REF: 3.1
TOP: I.C.i.c
MSC: Remembering
6. The proteins
expressed by a cell under given conditions are known collectively as a:
|
a. |
proteome |
d. |
gene |
|
b. |
genome |
e. |
ribosome |
|
c. |
protease |
|
|
ANS:
A
DIF:
Easy
REF:
3.1
TOP: I.C.i.d
MSC: Remembering
7. Fred
Neidhardt carried out experiments to define the proteome of a cell by using:
|
a. |
genetic analysis |
|
b. |
X-ray crystallography |
|
c. |
two-dimensional
polyacrylamide gel electrophoresis |
|
d. |
protein synthesis |
|
e. |
subcellular fractionation |
ANS:
C
DIF:
Easy
REF:
3.1
TOP: I.C.i.d
MSC: Remembering
8. The
most highly expressed proteins in a cell are the __________ proteins and the
__________ factors.
|
a. |
transport; transcription |
d. |
enzymatic; catalytic |
|
b. |
ribosomal; translation |
e. |
replication; transcription |
|
c. |
structural; replication |
|
|
ANS:
B
DIF: Medium
REF: 3.1
TOP: I.C.i.d
MSC: Remembering
9. __________
is impractical for proteins of a flexible nature.
|
a. |
Electrophoresis |
d. |
Fractionation |
|
b. |
Sonication |
e. |
Ultracentrifugation |
|
c. |
X-ray crystallography |
|
|
ANS:
C
DIF: Medium
REF: 3.1
TOP: I.B.iii.a
MSC: Understanding
10. The
2D-PAGE separation of macromolecules is dependent on all of the following
EXCEPT:
|
a. |
size |
d. |
DNA sequence |
|
b. |
charge |
e. |
voltage applied |
|
c. |
pH |
|
|
ANS: D
DIF:
Easy
REF: 3.1
TOP: I.C.ii
MSC: Understanding
11. Transport
__________ mediate both active and passive transport.
|
a. |
polysaccharides |
d. |
hopanoids |
|
b. |
proteins |
e. |
sterols |
|
c. |
lipids |
|
|
ANS:
B
DIF:
Easy
REF:
3.2
TOP: II.C
MSC: Remembering
12. Specific
membrane components, particularly __________, determine which substances are
transported across the membrane.
|
a. |
phospholipids |
d. |
polysaccharides |
|
b. |
proteins |
e. |
leaflets |
|
c. |
ions |
|
|
ANS:
B
DIF: Medium
REF: 3.2
TOP: II.C
MSC: Remembering
13. How
many ATP molecules are needed by E.
coli to transport vitamin B12 across
the inner cell membrane into the cytoplasm?
|
a. |
0 |
d. |
4 |
|
b. |
1 |
e. |
8 |
|
c. |
2 |
|
|
ANS:
C
DIF:
Easy
REF:
3.2
TOP: II.C.iv
MSC: Remembering
14. A
medically important example of active transport is that of drug __________
proteins powered by the hydrogen ion gradient.
|
a. |
efflux |
d. |
diffusion |
|
b. |
porin |
e. |
lysis |
|
c. |
membrane-permeant |
|
|
ANS:
A
DIF: Medium
REF: 3.2
TOP: II.C.iv
MSC: Remembering
15. The concentration
of __________ increases when bacteria are starving or in the stationary phase.
|
a. |
lipoproteins |
d. |
terpenoids |
|
b. |
proteins |
e. |
cardiolipin |
|
c. |
cholesterols |
|
|
ANS:
E
DIF: Medium
REF: 3.2
TOP: II.D.i
MSC: Remembering
16. Profiles
of which component of the membrane may be used to identify certain kinds of
pathogens?
|
a. |
lipoproteins |
d. |
polysaccharides |
|
b. |
proteins |
e. |
leaflets |
|
c. |
fatty acids |
|
|
ANS: C
DIF: Medium
REF: 3.2
TOP: II.D.i.a
MSC: Remembering
17. All
archaeal phospholipids have a(n) __________ link between glycerol and the lipid
component.
|
a. |
ester |
d. |
unsaturated |
|
b. |
ether |
e. |
phosphatidyl |
|
c. |
ethanolamine |
|
|
ANS:
B
DIF: Medium
REF: 3.2
TOP: II.D.ii.a
MSC: Remembering
18. __________
reinforce and stiffen membranes in bacteria.
|
a. |
Hopanoids |
d. |
Peptidoglycans |
|
b. |
Plyamines |
e. |
Lipids |
|
c. |
Sterols |
|
|
ANS:
A
DIF: Medium
REF: 3.2
TOP: II.A
MSC: Understanding
19. All
of the following statements regarding phospholipids of the cell membrane are
true EXCEPT:
|
a. |
They consist of glycerol
with ester links to two fatty acids and a phosphoryl group. |
|
b. |
They impart rigidity to the
membrane. |
|
c. |
All face each other, tail
to tail. |
|
d. |
The two layers in the
bilayer are called leaflets. |
|
e. |
They give the membrane a consistent
thickness. |
ANS:
B
DIF: Medium
REF: 3.2
TOP: II.A
MSC: Understanding
20. Functions
of the cytoplasmic membrane include all of the following EXCEPT:
|
a. |
permeability barrier |
d. |
transport |
|
b. |
assemble proteins |
e. |
structural support |
|
c. |
store energy |
|
|
ANS:
B
DIF: Medium
REF: 3.2
TOP: II.A | II.B | II.C
MSC: Understanding
21. Which
of the following molecules can be easily transported by passive diffusion?
|
a. |
HCHO |
d. |
CO2 |
|
b. |
CH3COOH |
e. |
both C and D |
|
c. |
H2O |
|
|
ANS:
E
DIF: Medium
REF: 3.2
TOP: II.C.i
MSC: Understanding
22. Efflux
pumps send antibiotics such as tetracycline, which binds to the 30S subunit of
bacterial ribosomes, out of the bacterial cells, enabling them to grow in the
presence of antibiotics. Which of the following therapeutic approaches will be
least effective?
|
a. |
Switch to an antibiotic
that is not a substrate of the efflux pump. |
|
b. |
Augment the treatment with
an efflux inhibitor. |
|
c. |
Increase the concentration
of tetracycline. |
|
d. |
Augment the treatment with
an ATP synthase inhibitor. |
|
e. |
None of the above
approaches will be effective. |
ANS:
C
DIF:
Difficult REF:
3.2
TOP: II.C
MSC: Creating
23. What
part of a cell is referred to as the sacculus?
|
a. |
nucleoid |
d. |
cell wall |
|
b. |
cytoplasm |
e. |
outer membrane |
|
c. |
cell membrane |
|
|
ANS: D
DIF:
Easy
REF: 3.3
TOP: III.A
MSC: Remembering
24. The
bacterial cell wall of Mycobacteria is highly hydrophobic due to presence of:
|
a. |
lipoproteins |
d. |
polysaccharides |
|
b. |
phenolic glycolipids |
e. |
glycoproteins |
|
c. |
phospholipids |
|
|
ANS:
B
DIF: Medium
REF: 3.3
TOP: III.C.iv
MSC: Remembering
25. The
lipopolysaccharide of the outer membrane is of medical importance because it
acts as a(n):
|
a. |
endotoxin |
d. |
enterotoxin |
|
b. |
exotoxin |
e. |
antibiotic |
|
c. |
toxoid |
|
|
ANS:
A
DIF:
Easy
REF:
3.3
TOP: III.D.ii
MSC: Remembering
26. The
__________ is the region between the cytoplasmic membrane and the outer
membrane in Gram-negative cells.
|
a. |
periplasm |
d. |
lipopolysaccharide |
|
b. |
cytoplasm |
e. |
S-layer |
|
c. |
lysozyme |
|
|
ANS:
A
DIF:
Easy
REF:
3.3
TOP: III.D.iv
MSC: Remembering
27. Eukaryotic
microbes that lack a cell wall possess __________ to circumvent osmotic shock.
|
a. |
Golgi bodies |
d. |
lysosomes |
|
b. |
contractile vacuoles |
e. |
gas vesicles |
|
c. |
endoplasmic reticulum |
|
|
ANS:
B
DIF: Easy
REF:
3.3
TOP: III.E.ii
MSC: Remembering
28. All
of the following are components of peptidoglycan EXCEPT:
|
a. |
N-acetylglucosamine |
d. |
amino acids |
|
b. |
N-acetylmuramic acid |
e. |
peptide cross-links |
|
c. |
lipopolysaccharide |
|
|
ANS:
C
DIF:
Easy
REF:
3.3
TOP: III.A.ii.a
MSC: Understanding
29. Which
is NOT a component of any bacterial cell’s wall?
|
a. |
peptidoglycan |
d. |
cellulose |
|
b. |
teichoic acids |
e. |
L-lysine |
|
c. |
N-acetylmuramic acid |
|
|
ANS:
D
DIF:
Easy
REF:
3.3
TOP: III.A | III.E.i
MSC: Understanding
30. All
of the following are true statements about bacterial S-layers EXCEPT:
|
a. |
They are commonly found in
Gram-positive cells as well as in archaea. |
|
b. |
They are a crystalline
layer consisting of protein or glycoprotein. |
|
c. |
They present a formidable
physical barrier to predators or parasites. |
|
d. |
They are found in bacteria
freshly isolated from natural sources. |
|
e. |
They are found in bacteria
isolated from laboratory cultures. |
ANS:
E
DIF:
Difficult REF:
3.3
TOP: III.C.iii
MSC: Understanding
31. The
thin layer of peptidoglycan in Gram-negative cells is believed, based on
calculations of __________, to be one or two sheets.
|
a. |
shape |
d. |
X-ray crystallography |
|
b. |
genetic analysis |
e. |
molecular density |
|
c. |
width |
|
|
ANS:
E
DIF: Medium
REF:
3.3
TOP: III.D.i
MSC: Understanding
32. Lipopolysaccharides
are found in:
|
a. |
all bacteria |
d. |
archaea |
|
b. |
Gram-positive bacteria |
e. |
eukaryotes |
|
c. |
Gram-negative bacteria |
|
|
ANS: C
DIF:
Easy
REF: 3.3
TOP: III.D.ii
MSC: Understanding
33. All
of the following are true about prokaryotic outer membranes EXCEPT:
|
a. |
They are lipid bilayers
composed of identical phospholipids. |
|
b. |
They are found only in
Gram-negative bacteria. |
|
c. |
They contain endotoxin. |
|
d. |
They contain proteins
involved in transport. |
|
e. |
They contain
lipopolysaccharide. |
ANS:
A
DIF:
Difficult REF:
3.3
TOP: III.D.ii
MSC: Understanding
34. In
Gram-negative bacteria, ATP synthase is typically found in:
|
a. |
cytoplasm |
d. |
inner membrane |
|
b. |
peptidoglycan layer |
e. |
outer membrane |
|
c. |
cell wall |
|
|
ANS:
D
DIF:
Easy
REF: 3.3
TOP: III.D.iv
MSC: Understanding
35. All
of the following represent components of eukaryotic organisms that help avoid
osmotic shock EXCEPT:
|
a. |
cellulose fibers |
d. |
contractile vacuole |
|
b. |
chitin |
e. |
peptidoglycan |
|
c. |
silicate exoskeleton |
|
|
ANS:
E
DIF:
Easy
REF:
3.3
TOP: III.E
MSC: Understanding
36. All
of the following are true for DNA-binding proteins EXCEPT:
|
a. |
They determine the shape of
the cell. |
|
b. |
They condense prokaryotic
DNA. |
|
c. |
They can act as regulators
of gene expression. |
|
d. |
They can form protective
crystalline structures around organized DNA. |
|
e. |
They help to keep cells
viable for a longer duration of time. |
ANS:
A
DIF: Medium
REF:
3.4
TOP: IV.A.i
MSC: Understanding
37. All
of the following are true of supercoiling in chromosomal DNA EXCEPT:
|
a. |
DNA doubles back and twists
upon itself. |
|
b. |
It facilitates RNA
transcription. |
|
c. |
It results in compaction. |
|
d. |
It is generated by gyrase. |
|
e. |
It is maintained by
DNA-binding proteins. |
ANS:
B
DIF:
Difficult REF:
3.4
TOP: IV.A.i
MSC: Understanding
38. A
__________ is a term used to designate a single messenger RNA molecule being
translated by multiple ribosomes.
|
a. |
coupled |
d. |
thylakoid |
|
b. |
periplasm |
e. |
polysome |
|
c. |
carboxysome |
|
|
ANS:
E
DIF:
Easy
REF:
3.4
TOP: IV.B.ii
MSC: Understanding
39. Which
of the following is true of Fts proteins?
|
a. |
They form a ring in the
area where cell division will occur. |
|
b. |
They aid in DNA
replication. |
|
c. |
They are involved in
peptidoglycan synthesis. |
|
d. |
They are involved in making
proteins. |
|
e. |
They are important in
transcription. |
ANS:
A
DIF:
Easy
REF:
3.5
TOP: V.B.ii
MSC: Understanding
40. The
partition that is a result of the inward growth of the cell envelope from
opposite directions is known as the:
|
a. |
divisome |
d. |
colony |
|
b. |
septum |
e. |
Z-ring |
|
c. |
wall |
|
|
ANS:
B
DIF:
Easy
REF:
3.5
TOP: V.B.ii
MSC: Understanding
41. Which
of the following is true regarding the asymmetrical cell division of Caulobacter crescentus?
|
a. |
It protects the Caulobacter crescentus from
predators. |
|
b. |
It is a result of sexual
reproduction. |
|
c. |
It is a result of polar
aging. |
|
d. |
It results in two cell types
(i.e., stalked cell and swarmer). |
|
e. |
It results in two cell
types, each with a monotrichous flagellum. |
ANS:
D
DIF:
Easy
REF:
3.6
TOP: VI.C
MSC: Remembering
42. Which
of the following is described as an attachment organelle that is a
membrane-bound extension of the cytoplasm?
|
a. |
pili |
d. |
stalks |
|
b. |
fimbriae |
e. |
flagella |
|
c. |
sex pili |
|
|
ANS:
D
DIF:
Easy
REF: 3.7
TOP: VII.D.iii
MSC: Remembering
43. Which
name refers to having flagella attached at one or both ends of the cell?
|
a. |
peritrichous |
d. |
bitrichous |
|
b. |
lophotrichous |
e. |
flagellated |
|
c. |
monotrichous |
|
|
ANS: B
DIF:
Easy
REF: 3.7
TOP: VII.E.iii
MSC: Remembering
44. Directed
movements toward or away from a chemical or physical signal are known as:
|
a. |
gliding |
d. |
locomotion |
|
b. |
flagellation |
e. |
slime layer |
|
c. |
chemotaxis |
|
|
ANS:
C
DIF:
Easy
REF:
3.7
TOP: VII.E.iv
MSC: Remembering
45. Light
is harvested by protein complexes called:
|
a. |
thylakoids |
d. |
storage granules |
|
b. |
carboxysomes |
e. |
magnetosomes |
|
c. |
gas vesicles |
|
|
ANS:
A
DIF:
Easy
REF:
3.7
TOP: VII.A
MSC: Understanding
46. Which
of the following materials found in storage granules is used as an energy
source?
|
a. |
gas vesicle |
d. |
glycogen |
|
b. |
sulfur |
e. |
magnetosome |
|
c. |
polyphosphate |
|
|
ANS:
D
DIF:
Easy
REF:
3.7
TOP: VII.B
MSC: Understanding
47. All
of the following are used by prokaryotic cells for attaching to solid surfaces
EXCEPT:
|
a. |
endospore |
d. |
fimbriae |
|
b. |
capsule |
e. |
pili |
|
c. |
stalks |
|
|
ANS:
A
DIF:
Easy
REF:
3.7
TOP: VII.D
MSC: Understanding
48. Which
of the following statements about the prokaryotic flagella is INCORRECT?
|
a. |
It is driven by the cell’s
transmembrane proton current. |
|
b. |
It is embedded in the
layers of the cell envelope. |
|
c. |
It is observed by electron
microscopy. |
|
d. |
It moves with a whiplike motion. |
|
e. |
It is used for chemotaxis. |
ANS:
D
DIF:
Easy
REF:
3.7
TOP: VII.E
MSC: Understanding
49. The
bacterial flagellum is a helical protein filament whose __________ motor moves
the cell in search of a more favorable environment.
|
a. |
shaking |
d. |
whiplike |
|
b. |
vibrating |
e. |
propeller-like |
|
c. |
wavelike |
|
|
ANS:
E
DIF:
Easy
REF:
3.7
TOP: VII.E.ii
MSC: Understanding
SHORT ANSWER
1. List
and briefly describe four components of a typical bacterial cell.
ANS:
Possible answers include: cytoplasm–gel-like network of proteins
and macromolecules; cell membrane surrounds cytoplasm, made of phospholipids
and hydrophobic proteins; cell wall surrounds cell membrane, rigid structure of
polysaccharides and peptides; lipopolysaccharide membrane surrounds cell wall
of Gram-negative cells, made of lipids and polysaccharides; capsule surrounds
envelope of some organisms, made of polysaccharides, prevents phagocytosis;
flagellum used for cell motility; nucleoid coiled chromosome not surrounded by
membrane.
DIF:
Medium REF:
3.1
TOP: I.A
MSC: Remembering
2. Describe
four ways cells can be broken open in order to isolate the cellular components.
ANS:
Mild detergent lysis disrupts the cell membrane without
denaturing cellular components. Sonication is the use of high-frequency sound
waves to disrupt cell membranes. Enzymes are proteins that can be used to break
open cells. Mechanical disruption uses methods such as a French press to lyse
cells.
DIF:
Difficult REF:
3.1
TOP: I.B.i
MSC: Remembering
3. What
are some of the limitations of X-ray crystallography?
ANS:
Crystallographic analysis can only be used for isolated
particles, and the particles’ function can’t be fully observed. It can only be
used for molecules capable of being crystallized, but is not useful for
analysis of soluble proteins or proteins that are flexible.
DIF:
Medium REF:
3.1
TOP: I.B.iii
MSC: Remembering
4. How
could you use green fluorescent protein as a reporter gene to compare
production of a specific protein in a cell culture when the culture is growing
under different environmental conditions?
ANS:
The gene for green fluorescent protein could be fused to the
gene that encodes the protein of interest. If that protein is produced when the
cells are growing under specific conditions, the cells will also produce the
green fluorescent protein. If that protein is not produced under certain growth
conditions, the cells will not appear fluorescent green. The cell cultures
could be grown using the different test conditions, and the degree of
fluorescence compared.
DIF:
Difficult REF:
3.1
TOP: I.B.iv
MSC: Understanding
5. Prokaryotic
genomes are more compact than eukaryotes, and the content of nucleic acids in
prokaryotes is much higher than in most eukaryotes. Explain this. Why is it
necessary for prokaryotes’ survival?
ANS:
Eukaryotes generally have large genomes with a large amount of
noncoding DNA. Prokaryotic genomes are compact, which means they have little
noncoding DNA. These small, compact genomes allow the cells to maximize
reproduction in an environment with resources that are typically limited. The
content of nucleic acids is approximately 8% by weight in E. coli, which is
much higher than in most eukaryotes. This allows the cell to maximize
chromosome replication and minimize the use of resources for protein-rich
cytoplasm.
DIF:
Medium REF:
3.1
TOP: I.C.i
MSC: Understanding
6. Explain
what happens when a cell comes into contact with water or with ethanol. Why is
70% ethanol commonly used to treat wounds and surfaces?
ANS:
Water can cross cell membranes by osmosis, but ethanol can
dissolve both polar and nonpolar substances, thus harming the integrity of the
membrane. In the presence of water, ethanol can denature proteins. The 70%
ethanol disrupts the membrane sufficiently that the cells lyse.
DIF:
Difficult REF:
3.1
TOP: I.C.i
MSC: Understanding
7. Why
can’t most kinds of bacteria be eaten as a major part of our diet?
ANS:
Prokaryotes in general have a higher nucleic acid content than
eukaryotes. This is advantageous to the microbe in that it maximizes
reproduction of its chromosomes, but is toxic to humans. We lack the enzymes to
digest the uric acid waste product of nucleic acids.
DIF:
Medium REF:
3.1
TOP: I.C.i.d
MSC: Understanding
8. Ribosomes
isolated by centrifugation are still active. What evidence demonstrates this?
ANS:
Ribosomes isolated by centrifugation can translate messenger RNA
in cell-free systems. Experiments in cell-free systems provide the basis for
much of our knowledge of protein synthesis.
DIF:
Difficult REF:
3.1
TOP: I.B.ii
MSC: Evaluating
9. The
bacterial membrane ATP synthase has two subunits. What is the location of each?
ANS:
One subunit is embedded in the cell membrane and the other
subunit is located in the cytoplasm.
DIF: Medium
REF:
3.2
TOP:
II.B
MSC: Understanding
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