Campbell’s Biology, 9e (Reece et al.)
Chapter 28 Protists
The taxonomy of the protists is still in a state of flux. Thus, few items here test students’ knowledge of
protist taxonomy. Most test items relate to the characteristics and functions of protist structures, as well
as to the protists’ metabolic, evolutionary, and ecological (especially with respect to humans) features.
There is an abundance of synthetic questions. Also featured are several sets of art questions tied together
by reference to a figure or to experimental data. There are two new sets of scenario questions, one
pertaining to Giardia lamblia and the other to the new “darling” of endosymbiosis, Paulinella
chromatophora.
Multiple-Choice Questions
1) All protists are
A) unicellular.
B) eukaryotic.
C) symbionts.
D) monophyletic.
E) mixotrophic.
2) Biologists have long been aware that the defunct kingdom Protista is polyphyletic. Which of these
statements is most consistent with this conclusion?
A) Many species within this kingdom were once classified as monerans.
B) Animals, plants, and fungi arose from different protist ancestors.
C) The eukaryotic condition has evolved more than once among the protists.
D) Chloroplasts among various protists are similar to those found in prokaryotes.
E) Some protists, all animals, and all fungi share a protist common ancestor, but these protists, animals,
and fungi are currently assigned to three different kingdoms.
3) According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria
originate?
A) from infoldings of the plasma membrane, coupled with mutations of genes for proteins in energy-
transfer reactions
B) from engulfed, originally free-living proteobacteria
C) by secondary endosymbiosis
D) from the nuclear envelope folding outward and forming mitochondrial membranes
E) when a protoeukaryote engaged in a symbiotic relationship with a protocell
4) Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without
the net loss of any genetic information?
A) conjugation
B) horizontal gene transfer
C) binary fission
D) phagocytosis
E) meiosis
5) An individual mixotroph loses its plastids, yet continues to survive. Which of the following most
likely accounts for its continued survival?
A) It relies on photosystems that float freely in its cytosol.
B) It must have gained extra mitochondria when it lost its plastids.
C) It engulfs organic material by phagocytosis or by absorption.
D) It has an endospore.
E) It is protected by a case made of silica.
6) Which of the following was derived from an ancestral cyanobacterium?
A) chloroplast
B) mitochondrion
C) hydrogenosome
D) mitosome
E) Two of the responses above are correct.
7) Which two genera have members that can evade the human immune system by frequently changing
their surface proteins?
1. Plasmodium
2. Trichomonas
3. Paramecium
4. Trypanosoma
5. Entamoeba
A) 1 and 2
B) 1 and 4
C) 2 and 3
D) 2 and 4
E) 4 and 5
8) Which of the following pairs of protists and their characteristics is mismatched?
A) apicomplexans–internal parasites
B) golden algae–planktonic producers
C) euglenozoans–unicellular flagellates
D) ciliates–red tide organisms
E) entamoebas–ingestive heterotrophs
9) Which of the following statements about dinoflagellates is true?
A) They possess two flagella.
B) All known varieties are autotrophic.
C) Their walls are usually composed of silica plates.
D) Many types lack mitochondria.
E) Their dead cells accumulate on the seafloor, and are mined to serve as a filtering material.
10) You are given an unknown organism to identify. It is unicellular and heterotrophic. It is motile,
using many short extensions of the cytoplasm, each featuring the 9 + 2 filament pattern. It has well-
developed organelles and three nuclei, one large and two small. This organism is most likely to be a
member of which group?
A) foraminiferans
B) radiolarians
C) ciliates
D) kinetoplastids
E) slime molds
11) Which of the following is characteristic of ciliates?
A) They use pseudopods as locomotory structures or as feeding structures.
B) They are relatively specialized cells.
C) They can exchange genetic material with other ciliates by the process of mitosis.
D) Most live as solitary autotrophs in fresh water.
E) They are often multinucleate.
12) Which process results in genetic recombination, but is separate from the process by which the
population size of Paramecium increases?
A) budding
B) meiotic division
C) mitotic division
D) conjugation
E) binary fission
13) Why is the filamentous morphology of the water molds considered a case of convergent evolution?
A) Water molds evolved from filamentous fungi.
B) Body shape reflects ancestor-descendant relationships among organisms.
C) In both cases, filamentous shape is an adaptation for the absorptive nutritional mode of a
decomposer.
D) Filamentous body shape is evolutionarily ancestral for all eukaryotes.
E) Both the first and second responses above are correct.
14) If we were to apply the most recent technique used to fight potato late blight to the fight against the
malarial infection of humans, then we would
A) increase the dosage of the least-expensive antimalarial drug administered to humans.
B) increase the dosage of the most common pesticide used to kill Anopheles mosquitoes.
C) introduce a predator of the malarial parasite into infected humans.
D) use a “cocktail” of at least three different pesticides against Anopheles mosquitoes.
E) insert genes from a Plasmodium-resistant strain of mosquito into Anopheles mosquitoes.
15) Diatoms are mostly asexual members of the phytoplankton. Diatoms lack any organelles that might
have the 9 + 2 pattern. They obtain their nutrition from functional chloroplasts, and each diatom is
encased within two porous, glasslike valves. Which question would be most important for one interested
in the day-to-day survival of individual diatoms?
A) How does carbon dioxide get into these protists with their glasslike valves?
B) How do diatoms get transported from one location on the water’s surface layers to another location on
the surface?
C) How do diatoms with their glasslike valves keep from sinking into poorly lit waters?
D) How do diatoms with their glasslike valves avoid being shattered by the action of waves?
E) How do diatom sperm cells locate diatom egg cells?
5
16) A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack
which of the following?
A) thalli
B) bladders
C) holdfasts
D) gel-forming polysaccharides
17) Which of the following is a characteristic of the water molds (oomycetes)?
A) the presence of filamentous feeding structures
B) zoospores that are spread by breezes
C) the same nutritional mode as possessed by cyanobacteria
D) a morphological similarity to fungi that is the result of common ancestry
E) a feeding Plasmodium
18) Reinforced, threadlike pseudopods that can perform phagocytosis are generally characteristic of
which group?
A) radiolarians and forams
B) gymnamoebas
C) entamoebas
D) amoeboid stage of cellular slime molds
E) oomycetes
19) A snail-like, coiled, porous test (shell) of calcium carbonate is characteristic of which group?
A) diatoms
B) foraminiferans
C) radiolarians
D) gymnamoebas
20) The chloroplasts of land plants are thought to have been derived according to which evolutionary
sequence?
A) cyanobacteria → green algae → land plants
B) cyanobacteria → green algae → fungi → land plants
C) red algae → brown algae → green algae → land plants
D) cyanobacteria → red algae → green algae → land plants
21) The chloroplasts of all of the following are thought to be derived from ancestral red algae, except
those of
A) golden algae.
B) diatoms.
C) dinoflagellates.
D) green algae.
E) brown algae.
22) A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue
light. This alga probably belongs to which group?
A) red algae
B) brown algae
C) green algae
D) dinoflagellates
E) golden algae
23) Green algae differ from land plants in that many green algae
A) are heterotrophs.
B) are unicellular.
C) have plastids.
D) have alternation of generations.
E) have cell walls containing cellulose.
24) If the Archaeplastidae are eventually designated a kingdom, and if land plants are excluded from this
kingdom, then what will be true of this new kingdom?
A) It will be monophyletic.
B) It will more accurately depict evolutionary relationships than does the current taxonomy.
C) It will be paraphyletic.
D) It will be a true clade.
E) It will be polyphyletic.
25) The best evidence for not classifying the slime molds as fungi comes from slime molds’
A) DNA sequences.
B) nutritional modes.
C) choice of habitats.
D) physical appearance.
E) reproductive methods.
26) Which pair of alternatives is highlighted by the life cycle of the cellular slime molds, such as
Dictyostelium?
A) prokaryotic or eukaryotic
B) unicellular or multicellular
C) diploid or haploid
D) autotroph or heterotroph
27) Which of the following statements concerning protists is true?
A) All protists have mitochondria, though in some species they are much reduced and known by
different names.
B) The primary organism that transmits malaria to humans by its bite is the tsetse fly.
C) All apicomplexans are autotrophic.
D) All slime molds have an amoeboid stage that may be followed by a stage during which spores are
produced.
E) Euglenozoans that are mixotrophic lack functional chloroplasts.
28) Which of the following is correctly described as a primary producer?
A) oomycete
B) kinetoplastid
C) apicomplexan
D) diatom
E) radiolarian
29) You are given the task of designing an aerobic, mixotrophic protist that can perform photosynthesis
in fairly deep water (for example, 250 m deep), and can also crawl about and engulf small particles.
With which two of the following structures would you provide your protist?
1. hydrogenosome
2. apicoplast
3. pseudopods
4. chloroplast from red alga
5. chloroplast from green alga
A) 1 and 2
B) 2 and 3
C) 2 and 4
D) 3 and 4
E) 4 and 5
30) You are given the task of designing an aquatic protist that is a primary producer. It cannot swim on
its own, yet must stay in well-lit surface waters. It must be resistant to physical damage from wave
action. It should be most similar to a(n)
A) diatom.
B) dinoflagellate.
C) apicomplexan.
D) red alga.
E) radiolarian.
31) Similar to most amoebozoans, the forams and the radiolarians also have pseudopods, as do some of
the white blood cells of animals (monocytes). If one were to erect a taxon that included all organisms
that have cells with pseudopods, what would be true of such a taxon?
A) It would be polyphyletic.
B) It would be paraphyletic.
C) It would be monophyletic.
D) It would include all eukaryotes.
32) You are designing an artificial drug-delivery “cell” that can penetrate animal cells. Which of these
protist structures should provide the most likely avenue for research along these lines?
A) pseudopods
B) apical complex
C) excavated feeding grooves
D) nucleomorphs
E) mitosomes
33) A gelatinous seaweed that grows in shallow, cold water and undergoes heteromorphic alternation of
generations is most probably what type of alga?
A) red
B) green
C) brown
D) yellow
34) Which of the following are actual mutualistic partnerships that involve a protist and a host
organism?
A) cellulose-digesting gut protists wood-eating termites
B) dinoflagellates reef-building coral animals
C) Trichomonas humans
D) algae certain foraminiferans
E) all except that involving humans
35) Living diatoms contain brownish plastids. If global warming causes blooms of diatoms in the
surface waters of Earth’s oceans, how might this be harmful to the animals that build coral reefs?
A) The coral animals, which capture planktonic organisms, may be outcompeted by the diatoms.
B) The coral animals’ endosymbiotic dinoflagellates may get “shaded out” by the diatoms.
C) The coral animals may die from overeating the plentiful diatoms, with their cases of silica.
D) The diatoms’ photosynthetic output may over-oxygenate the water.
Art Questions
You are given five test tubes, each containing an unknown protist, and your task is to read the following
description and match these five protists to the correct test tube.
In test tube 1, you observe an organism feeding. Your sketch of the organism looks very similar to
Figure 28.1. When light, especially red and blue light, is shone on the tubes, oxygen bubbles accumulate
on the inside of test tubes 2 and 3. Chemical analysis of test tube 3 indicates the presence of substantial
amounts of silica. Chemical analysis of test tube 2 indicates the presence of a chemical that is toxic to
fish and humans. Microscopic analysis of organisms in test tubes 2, 4, and 5 reveals the presence of
permanent, membrane-bounded sacs just under the plasma membrane. Microscopic analysis of
organisms in test tube 4 reveals the presence of an apicoplast in each. Microscopic analysis of the
contents in test tube 5 reveals the presence of one large nucleus and several small nuclei in each
organism.
Figure 28.1
36) Test tube 2 contains
A) Paramecium.
B) Navicula (diatom).
C) Pfiesteria (dinoflagellate).
D) Entamoeba.
E) Plasmodium.
37) Test tube 4 contains
A) Paramecium.
B) Navicula (diatom).
C) Pfiesteria (dinoflagellate).
D) Entamoeba.
E) Plasmodium.
38) Test tube 5 contains
A) Paramecium.
B) Navicula (diatom).
C) Pfiesteria (dinoflagellate).
D) Entamoeba.
E) Plasmodium.
39) Test tube 3 contains
A) Paramecium.
B) Navicula (diatom).
C) Pfiesteria (dinoflagellate).
D) Entamoeba.
E) Plasmodium.
Scenario Questions
The next few questions refer to the following description and Table 28.1.
Diatoms are encased in Petri-platelike cases (valves) made of translucent hydrated silica whose
thickness can be varied. The material used to store excess calories can also be varied. At certain times,
diatoms store excess calories in the form of the liquid polysaccharide, laminarin, and at other times as
oil. The following are data concerning the density (specific gravity) of various components of diatoms,
and of their environment.
Table 28.1 Specific Gravities of Materials Relevant to Diatoms
Material
Specific Gravity
(kg/m3)
Pure water
1,000
Seawater
1,026
Hydrated silica
2,250
Liquid laminarin
1,500
Diatom oil
910
40) Water’s density and, consequently, its buoyancy decrease at warmer temperatures. Based on this
consideration and using data from Table 28.1, at which time of year should one expect diatoms to be
storing excess calories mostly as oil?
A) mid-winter
B) early spring
C) late summer
D) late fall
41) Judging from Table 28.1 and given that water’s density and, consequently, its buoyancy decrease at
warmer temperatures, in which environment should diatoms (and other suspended particles) sink most
slowly?
A) cold fresh water
B) warm fresh water
C) cold seawater
D) warm seawater
E) warm brackish water