73 Chapter 6—Marine Microbes
Chapter 6—Marine Microbes
MULTIPLE CHOICE
1. The most abundant microbes in the marine environment are:
a.
bacteria.
b.
diatoms.
c.
foraminiferans.
d.
viruses.
e.
dinoflagellates.
2. Viruses are not considered “living” by some biologists because they
a.
have no metabolism.
b.
do not reproduce.
c.
cannot move.
d.
contain protein.
3. Virus replication only occurs
a.
when conditions stress the virus.
b.
at regular intervals.
c.
inside a host cell.
d.
outside of eukaryote cells.
e.
when virus particles undergo binary fission.
4. A phage
a.
can be found in all living organisms.
b.
is specific to a particular organism.
c.
is found in mammals.
d.
is specific for bacteria.
e.
is specific for vertebrates.
5. Virus size is
a.
300 to 400 m.
b.
10 to 400 mm.
c.
10 to 200 cm.
d.
10 to 400 nm.
e.
300 to 400 mm.
6. Outside a host cell a virus is called a(n):
a.
capsid.
b.
virion.
c.
nucleocapsid.
d.
envelope.
e.
glochidia.
7. The protein coat covering the nucleic acid core of the virus is called the
a.
capsid.
b.
virion.
c.
nucleocapsid.
d.
envelope.
e.
membrane.
8. The combination of a virus’s genetic material and protein is called the
a.
capsid.
b.
virion.
c.
nucleocapsid.
d.
envelope.
e.
transfer RNA.
9. You are a virologist studying a particularly pathogenic virus that infects sea turtles. In the course of
your research, you discover that the virus is destroyed by a protein-digesting enzyme. The structure
most vulnerable to this enzyme must be the viral
a.
membrane.
b.
envelope.
c.
DNA.
d.
capsid.
10. A virus’s nucleocapsid is sometimes covered with a(n):
a.
capsid.
b.
virion.
c.
organic material.
d.
envelope.
e.
membrane.
11. A virus with a capsid with twenty triangular faces is called:
a.
icosahedral.
b.
helical.
c.
binal.
d.
filamentous.
e.
dodecahedral.
12. A viral lytic cycle is characterized by:
a.
rapid infection and emergence.
b.
rapid infection, replication of nucleic acids and proteins, assembly of virions and release
by rupture.
c.
a virus remaining in the host cell then being released.
d.
a viral nucleic acid being inserted into the host genome and possibly residing through
multiple cell divisions prior to lytic.
13. A viral lysogenic cycle is characterized by:
a.
rapid infection and emergence.
b.
rapid infection, replication of nucleic acids and proteins, assembly of virions and release
by rupture.
c.
a virus remaining in the host cell then being released.
d.
a viral nucleic acid being inserted into the host genome and possibly residing through
multiple cell divisions prior to lytic.
14. The abundance and diversity of marine viruses are considered
a.
low abundance with high diversity.
b.
high abundance and low diversity.
c.
low abundance and low diversity.
d.
high abundance and high diversity.
15. Some viruses can change geochemical cycles leading to:
a.
a change in seawater pH.
b.
reduction in surface oxygen.
c.
modification of salinity.
d.
an effect on global warming.
e.
increased geothermal activity.
16. Viruses can control host population
a.
by reducing their numbers.
b.
by modifying their growth rate.
c.
by increasing their capacity to expand.
d.
by making them more attractable to predators.
e.
by attaching to the host membrane, causing the host cell to sink.
17. Bacteria belong to the domain
a.
Eubacteria.
b.
Eukarya.
c.
Archaea.
d.
Animalia.
e.
Protista.
18. Bacteria reproduce by:
a.
meiosis.
b.
cell fusion.
c.
binary fission.
d.
cloning.
e.
auxospore formation.
19. The process of producing high-energy foods from inorganic compounds using sunlight energy is
called:
a.
heterotrophy.
b.
chemosynthesis.
c.
photosynthesis.
d.
grazing.
e.
solar irradiation.
20. The process of producing food from inorganic compounds using high energy compounds as a source
of energy is called:
a.
photosynthesis.
b.
chemosynthesis.
c.
heterotrophy.
d.
grazing.
e.
solar irradiation.
21. Chemosynthetic bacteria are unique:
a.
in not requiring CO2.
b.
because they use energy derived from chemicals.
c.
because they can produce food with low light.
d.
and are very common in the twilight depths.
e.
because many forms are also bioluminescent.
22. Facultative anaerobic bacteria
a.
do not tolerate oxygen.
b.
respire in low oxygen.
c.
are chemosynthetic.
d.
require oxygen to perform photosynthesis.
e.
are common in open water samples.
23. Anaerobic organisms live in ____ areas.
a.
nitrogen-free.
b.
oxygen-rich.
c.
oxygen-free.
d.
hydrogen-free.
e.
carbon-free.
77 Chapter 6—Marine Microbes
24. The process where DNA is duplicated and then the cell divides into two cells is called:
a.
mitosis.
b.
meiosis.
c.
binary fusion.
d.
auxospore.
e.
fusion.
25. A rod-shaped bacteria is called:
a.
coccus.
b.
auxospore.
c.
bacillus.
d.
bacteriophage.
e.
spirillus.
26. A spherical shaped bacteria is called:
a.
coccus.
b.
auxospore.
c.
bacillus.
d.
bacteria phage.
e.
spirillus.
27. Which primary producer listed below is considered the most abundant life form in the sea?
a.
Dunaliella
b.
Synechoccus
c.
Methanococcus
d.
Pryolobus
e.
Prochlorococcus
28. The pigment ____ is commonly found in bacteria but not land plants.
a.
chlorophyll a
b.
chlorophyll b
c.
xanthophyll
d.
phycocyanin
e.
carotene.
29. Accessory photosynthetic pigments are important because:
a.
they can capture different light wavelengths.
b.
they enable chromatic adaptation with depth and seasons.
c.
they shield the cell against damaging wavelengths.
d.
all the above.
78 Chapter 6—Marine Microbes
30. A structure formed from the combination of cyanobacterial microbes and sediments is called:
a.
a coral reef.
b.
a bacteria reef.
c.
a stromatolite.
d.
a stalactite.
e.
a stalagmite.
31. The absorption of external organic matter by bacteria is called:
a.
heterotrophy.
b.
autotrophy.
c.
tertiary.
d.
osmotrophy.
e.
omnivory.
32. Heterotrophic bacteria are able to break down large food items
a.
by ingesting them with pseudopods.
b.
with exoenzymes.
c.
by breaking them up with cilia.
d.
by crushing with their larger relative size.
e.
by using their cell membranes to pinch the food into smaller pieces.
33. An important role of bacteria is:
a.
primary producers.
b.
decomposers.
c.
nitrogen fixation.
d.
all of the above
34. Nutrient recycling in the marine environment is performed by:
a.
cyanobacteria.
b.
heterotrophic bacteria.
c.
autotrophic bacteria.
d.
purple bacteria.
e.
sulfur bacteria.
35. Nitrogen fixation is carried out by:
a.
nitrifying bacteria.
b.
prochlorophytes.
c.
cyanobacteria.
d.
all heterotrophic bacteria.
e.
only spirilli-shaped bacteria.
79 Chapter 6—Marine Microbes
36. A special structure on certain cyanobacteria for nitrogen fixation is called a(n):
a.
ammonia cyst.
b.
homocyst.
c.
heterocyst.
d.
nematocyst.
e.
pneumatocyst.
37. Nitrogen fixation and nitrification are directly important processes for:
a.
heterotrophic animals.
b.
heterotrophic bacteria.
c.
autotrophic organisms.
d.
fungi.
e.
viruses.
38. A bacteria sample is taken from the immediate vicinity of a hydrothermal vent. You would expect for
it to most likely contain
a.
diatoms.
b.
hyperthermophiles.
c.
lignicolous fungi.
d.
cyanobacteria.
39. Zooxanthellae are members of the following group of Eukaryotes:
a.
diatoms.
b.
coccolithophores.
c.
amoebas.
d.
dinoflagellates.
e.
ciliates.
40. Harmful algal bloom toxins are produced by:
a.
diatoms.
b.
coccolithophores.
c.
amoebas.
d.
dinoflagellates.
e.
radiolarians.
41. Diatoms, coccolithophores and silicoflagellates all belong to the domain:
a.
Eukarya.
b.
Eubacteria.
c.
Archaea.
d.
Anthophyta.
e.
Protista.
80 Chapter 6—Marine Microbes
42. All of following marine microbes have hard skeletal parts that sink to the bottom, forming oceanic
sediments, except
a.
radiolarians.
b.
coccolithophores.
c.
foraminiferans.
d.
diatoms.
e.
fungi.
43. The frustule of diatoms is made of:
a.
cellulose.
b.
calcium carbonate.
c.
silica.
d.
protein.
e.
starch.
44. The deposits of the following phytoplankton are used commercially in polishes and filtering devices:
a.
dinoflagellates.
b.
foraminiferans.
c.
coccolithophores.
d.
diatoms.
e.
radiolarians.
45. Pseudopods are structures that are primarily found in:
a.
silicoflagellates.
b.
amoeboid protozoans.
c.
coccolithophores.
d.
diatoms.
e.
dinoflagellates.
46. You add a weak acid solution to a sample of foraminifera shells, and they bubble and fizz. This tells
you that the external shells of foraminiferans are composed of:
a.
silica.
b.
protein.
c.
cellulose.
d.
calcium carbonate.
e.
starch.
81 Chapter 6—Marine Microbes
47. The following amoeboid protozoans are important sources of silica deposits in some areas of the
world:
a.
diatoms.
b.
silicoflagellates.
c.
radiolarians.
d.
foraminiferans.
e.
ciliates.
48. Tintinnids are examples of the following protozoans:
a.
radiolarians.
b.
ciliates.
c.
diatoms.
d.
foraminiferans.
e.
dinoflagellates.
49. The ecological role of fungi is that of:
a.
decomposers.
b.
producers.
c.
grazers.
d.
predators.
e.
herbivores.
50. A very close association with two species is called:
a.
adjoining.
b.
symbiosis.
c.
predator -prey.
d.
host-fungus.
e.
competition.
TRUE/FALSE
51. The only autotrophic bacteria are chemosynthetic bacteria.
52. Deep-sea vent bacteria do not rely on the sun as a source of energy.
53. Since purple and green bacteria do not use water in their autotrophic processes, they are not
photosynthetic.
82 Chapter 6—Marine Microbes
54. Nitrifying bacteria are important in the conversion of nitrogen gas to usable forms of nitrogen.
55. Chemosynthesis is less efficient than photosynthesis.
56. Amoeboid protozoans are autotrophic.
57. The toxins of dinoflagellates are destroyed by cooking or heating.
58. Diatoms reproduce by binary fission.
59. Ciliates are autotrophic members of the phytoplankton community.
60. Fungi are surrounded by a cell wall made of chitin.
61. Fungi are usually found in pelagic habitats.
MATCHING
Match the description with the most closely associated term.
a.
icosahedral heads with helical tails
b.
protein subunit of the capsid spiral around the central core of the nucleic acid
c.
capsid with twenty triangular faces
62. Icosahedral
63. Helical
64. Binal
Match the bacteria-caused process with the most closely associated characteristic.
a.
alteration of the electrical charge
b.
settling out of large particles
c.
alteration of the pH
83 Chapter 6—Marine Microbes
65. Consolidation
66. Lithification
67. Sedimentation
Match the words with the most closely associated words.
a.
NH4+ to NO2– and NO3–
b.
can break the bonds in N2 molecules
c.
N2 to NH3
68. Nitrogenase
69. Nitrogen fixation
70. Nitrification
Match the words with the most closely associated phrase.
a.
conidiospores
b.
budding
c.
ascocarp
71. Marine yeast asexual reproduction
72. Filamentous marine fungi asexual reproduction
73. Filamentous sexual reproduction
Match the description with the most closely associated word.
a.
DHA fatty acid
b.
planktonic decomposer
c.
wasting disease
74. Labyrinthulids
75. Thraustochytrids
76. Schizochytrium
Match the characteristic with its most closely associated organisms.
a.
disc-shaped calcareous scales
b.
membranous sacs
c.
silicon frustules
84 Chapter 6—Marine Microbes
77. Diatoms
78. Coccoliths
79. Alveolates
Match the dinoflagellate characteristic with those it is most closely associated with.
a.
either osmotrophy or phagotrophy
b.
important symbionts of coral
c.
paralytic shellfish poisoning
80. Zooxanthellae
81. “Red Tide”
82. Mixotrophic
Match the description with the most closely associated word.
a.
have a lorica
b.
few body cilia
c.
dense and uniform distribution of cilia
83. Scuticocilates
84. Oligotrichs
85. Tinitinnids
Match the words with the most closely associated group.
a.
collar of microvilli traps bacteria prey
b.
siliceous perforated shell
c.
reticulopods
86. Foraminiferans
87. Radiolarians
88. Choanoflagellates
Match the description with the most closely associated group.
a.
prokaryote in some ways similar to eukaryotes
b.
original inhabitants of the sea
c.
nucleus and membrane-bound organelle
89. Eubacteria
90. Archaea
91. Eukarya
ESSAY
92. Briefly explain why viruses are not considered living organisms.
93. Briefly describe 3 ecological roles of viruses.
94. What would happen if organisms that play the role of heterotrophic bacteria did not exist in the marine
environment?
95. Given that oxygen is toxic to anaerobic bacteria, describe how they must have adapted to survive in
the present environmental conditions on Earth.
96. Compare and contrast aerobic and aerobic bacterial photosynthesis in terms of a) the source of
electrons used by each; b) the final products of both reactions.
97. What is meant by the term “paralytic shellfish poisoning”? What are the symptoms, and what
organisms are responsible for this disease?
98. What is diatomaceous earth? How is it used commercially?
99. Describe the feeding behavior and biology of amoeboid protozoans.
100. You are asked to determine whether sulfur bacteria are active in a particular area of an estuary. What
observations or tests can you perform to confirm this activity?
101. What is the importance of nitrogen-fixation to autotrophic organisms?
102. Describe the symbiotic relationship between zooxanthellae and their hosts. How do both benefit from
the relationship?
103. Toxic dinoflagellates can directly harm other organisms during bloom periods by secreting their toxins
in the water or by being consumed and concentrated in the tissues of filter-feeding organisms. Can you
think of ways in which blooms of non-toxic dinoflagellates may harm other organisms in the water?
104. Based on your knowledge of the distribution of CO2 in the marine environment and the pattern of
pressure with depth, explain why calcium carbonate deposits of coccolithophores and foraminiferans
are not found below 5000 m.