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Protists are alike in that all are
Biologists have long been aware that the defunct kingdom Protista is paraphyletic. Which of these statements is both true and 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 only once among the protists, and all eukaryotes are descendants of that first eukaryotic cell.
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.
The strongest evidence for the endosymbiotic origin of eukaryotic organelles is the
similarity between extant prokaryotes and which of the following?
A) nuclei and chloroplasts
B) mitochondria and chloroplasts
C) cilia and mitochondria
D) mitochondria and nuclei
E) mitochondria and cilia
According to the endosymbiotic theory of the origin of eukaryotic cells, how did
A) from infoldings of the plasma membrane, coupled with mutations of genes for
proteins in energy- transfer reactions
B) from engulfed, originally free- living prokaryotes
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 protobiont
Which of these statements is false and therefore does not support the hypothesis that
certain eukaryotic organelles originated as bacterial endosymbionts? Such organelles
A) are roughly the same size as bacteria.
B) can be cultured on agar, because they make all their own proteins.
C) contain circular DNA molecules.
D) have ribosomes that are similar to those of bacteria.
E) have internal membranes that contain proteins homologous to those of bacterial
Which process allowed the nucleomorphs of chlorarachniophytes to be first reduced, and
then (in a few species) lost altogether, without the loss of any genetic information?
B) horizontal gene transfer
C) binary fission
Which organisms represent the common ancestor of all photosynthetic plastids found in
A) autotrophic euglenids
D) red algae
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 siliceous case.
Which of these was not derived from an ancestral alpha proteobacterium?
A biologist discovers a new unicellullar organism that possesses more than two flagella and
two small, but equal- sized, nuclei. The organism has reduced mitochondria (mitosomes),
no chloroplasts, and is anaerobic. To which clade does this organism probably belong?
B) the diplomonads
C) the ciliates
E) the euglenids
Which two genera have members that can evade the human immune system by frequently
changing their surface proteins?
Which statement regarding resistance is false ?
A) Many of the oomycetes that cause potato late blight have become resistant to pesticides.
B) Many of the mosquitoes that transmit malaria to humans have become resistant to pesticides.
C) Many of the malarial parasites have become resistant to antimalarial drugs.
D) Many humans have become resistant to antimalarial drugs.
E) Trichomonas vaginalis is resistant to the normal acidity of the human vagina.
Which of these taxa contains species that produce potent toxins that can cause extensive
fish kills, contaminate shellfish, and poison humans?
A) red algae
E) golden algae
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
Which of these statements about dinoflagellates is false ?
A) They possess two flagella.
B) Some cause red tides.
C) Their walls are composed of cellulose plates.
D) Many types contain chlorophyll.
E) Their dead cells accumulate on the seafloor, and are mined to serve as a filtering
Which group includes members that are important primary producers in ocean food webs,
causes red tides that kill many fish, and may even be carnivorous?
D) brown algae
E) golden algae
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
E) slime molds
Which of the following is not characteristic of ciliates?
A) They use cilia as locomotory structures or as feeding structures.
B) They are relatively complex cells.
C) They can exchange genetic material with other ciliates by the process of mitosis.
D) Most live as solitary cells in fresh water.
E) They have two or more nuclei.
Which process results in genetic recombination, but is separate from the process wherein
the population size of Paramecium increases?
B) meiotic division
C) mitotic division
E) binary fission
Why is the filamentous morphology of the water molds considered a case of convergent evolution with the hyphae (threads) of fungi?
A) Fungi are closely related to the water molds.
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 A and B are correct.
The Irish potato famine was caused by an organism that belongs to which group?
If one were to apply the most recent technique used to fight potato late blight to the fight against the malarial infection of humans, then one 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 ʺ cocktailʺ of at least three different pesticides against Anopheles mosquitoes.
E) insert genes from a Plasmodium- resistant strain of mosquito into Anopheles mosquitoes
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 waterʹ 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?
A large seaweed that floats freely on the surface of deep bodies of water would be expected
to lack which of the following?
E) gel- forming polysaccharides
The following are all characteristic of the water molds (oomycetes) except
A) the presence of filamentous feeding structures.
B) flagellated zoospores.
C) a nutritional mode that can result in the decomposition of dead organic matter.
D) a morphological similarity to fungi that is the result of evolutionary convergence.
E) a feeding plasmodium.
Using dead diatoms to ʺ pumpʺ CO2 to the seafloor is feasible only if dead diatoms sink quickly. Consequently, application of mineral fertilizers, such as iron, should be most effective at times when diatom
A) valves are thickest, and laminarin is being produced rather than oil.
B) valves are thickest, and oil is being produced rather than laminarin.
C) valves are thinnest, and laminarin is being produced rather than oil.
D) valves are thinnest, and oil is being produced rather than laminarin.
Theoretically, which two of the following present the richest potential sources of silica?
1. marine sediments consisting of foram tests
2. marine sediments consisting of diatom cases (valves)
3. marine sediments consisting of radiolarian shells
4. marine sediments consisting of dinoflagellate plates
Thread- like pseudopods that can perform phagocytosis are generally characteristic of
A) radiolarians and forams
D) amoeboid stage of cellular slime molds
Which of the following produce the dense glassy ooze found in certain areas of the
deep- ocean floor?
A snail- like, coiled, porous test (shell) of calcium carbonate is characteristic of which
Typically as cells grow, their increase in volume outpaces their increase in surface area, and continued survival requires undergoing asexual reproduction to reestablish a healthy surface area to volume ratio. Thus, which of these is least likely to contribute to the ability of a single- celled foraminiferan to grow to a diameter of several centimeters?
A) Its threadlike pseudopods dramatically increase its surface area to volume ratio.
B) Its symbiotic algae provide oxygen to the cytoplasm.
C) Its symbiotic algae absorb metabolic waste products from the cytoplasm.
D) Its symbiotic algae provide glucose to the cytoplasm.
E) Its calcium carbonate test contributes extra mass.
What makes certain red algae appear red?
A) They live in warm coastal waters.
B) They possess pigments that reflect and transmit red light.
C) They use red light for photosynthesis.
D) They lack chlorophyll.
E) They contain the pigment bacteriorhodopsin
The largest seaweeds belong to which group?
A) red algae
B) green algae
C) brown algae
D) golden algae
The chloroplasts of land plants are thought to have been derived according to which
A) cyanobacteria → green algae → land plants
B) cyanobacteria → green algae → fungi → land plants
C) red algae → brown algae → green algae → land plants
D) red algae → cyanobacteria → land plants
E) cyanobacteria → red algae → green algae → land plants
The chloroplasts of all of the following are derived from ancestral red algae, except those of
A) golden algae.
D) green algae.
E) brown algae.
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
E) golden algae
Green algae often differ from land plants in that some green algae
A) are heterotrophs.
B) are unicellular.
C) have plastids.
D) have alternation of generations.
E) have cell walls containing cellulose
Which taxon of eukaryotic organisms is thought to be directly ancestral to the plant
A) golden algae
E) green algae
If the Archaeplastidae are eventually designated a kingdom, and if the 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
C) It will be paraphyletic.
D) It will be a true clade.
E) It will be polyphyletic.
The best evidence for not classifying the slime molds as fungi comes from slime moldsʹ
A) DNA sequences.
B) nutritional modes.
C) choice of habitats.
D) physical appearance.
E) reproductive methods.
Which pair of alternatives is highlighted by the life cycle of the cellular slime molds, such as
A) prokaryotic or eukaryotic
B) plant or animal
C) unicellular or multicellular
D) diploid or haploid
E) autotroph or heterotroph
Which of the following correctly pairs a protist with one of its characteristics?
A) diplomonads : micronuclei involved in conjugation
B) ciliates : pseudopods
C) apicomplexans : parasitic
D) gymnamoebas : calcium carbonate test
E) foraminiferans : abundant in soils
Which of the following statements concerning protists is false ?
A) All protists are eukaryotic organisms; many are unicellular or colonial.
B) The primary organism that transmits malaria to humans by its bite is the tsetse fly.
C) All apicomplexans are parasitic.
D) Cellular slime molds have an amoeboid stage that may be followed by a stage during which spores are produced.
E) Euglenozoans that are mixotrophic contain chloroplasts.
Which of the following is correctly described as a primary producer?
A certain unicellular eukaryote has a siliceous (glasslike) shell and autotrophic nutrition. To
which group does it belong?
C) brown algae
You are given the task of designing an aerobic, mixotrophic protist that can perform photosynthesis in fairly deep water (e.g., 250 m deep), and can also crawl about and engulf small particles. With which two of these structures would you provide your protist?
4. chloroplast from red alga
5. chloroplast from green alga
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)
D) red alga.
Some protists, formerly united as the ʺ amitochondriateʺ clade, have recently been shown to
be rather diverse. Some of them possess neither mitochondria nor mitochondrial genes (and have been classified as fungi). Others possess no mitochondria, but do have mitochondrial genes in their nuclear genome. Still others have modified mitochondria (viz. mitoses or hydrogenosomes). Which statement(s) represent(s) consequences of these recent findings?
1. The amitochondriates do not comprise a true clade.
2. The ʺ amitochondriate hypothesisʺ concerning the root of the eukaryotic tree has been strengthened.
3. Just as there is a diversity of cyanobacterial descendants among eukaryotes, so too is there a diversity of alpha- proteobacterial descendants among the eukaryotes.
4. If the amitochondriate organisms continued to be recognized as a taxon, this taxon would be polyphyletic.
5. Horizontal gene transfer involving mitochondrial genes has occurred in some amitochondriate organisms.
Similar to most amoebozoans, the forams and the radiolarians also have pseudopods, as do
the white blood cells of animals. If one were to erect a taxon that included all organisms
that have cells with pseudpods, 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.
You are designing an artificial drug- delivery ʺ cellʺ that can penetrate animal cells. Which of
these protist structures should provide the most likely avenue for research along these
B) apical complex
C) excavated feeding grooves
A gelatinous seaweed that grows in shallow, cold water and undergoes heteromorphic
alternation of generations is most probably what type of alga?
Which of these are actual mutualistic partnerships that involve a protist and a host
A) cellulose- digesting gut protists : wood- eating termites
B) dinoflagellates : reef- building coral animals
C) Trichomonas : humans
D) algae : certain foraminiferans
E) all except C
Which of the following statements concerning living phytoplanktonic organisms are true?
1. They are important members of communities surrounding deep- sea hydrothermal vents.
2. They are important primary producers in most aquatic food webs.
3. They are important in maintaining oxygen in Earthʹ s seas and atmosphere.
4. They are most often found growing in the sediments of seas and oceans.
5. They can be so concentrated that they affect the color of seawater.
Plastids that are surrounded by more than two membranes are evidence of
A) evolution from mitochondria.
B) fusion of plastids.
C) origin of the plastids from archaea.
D) secondary endosymbiosis.
E) budding of the plastids from the nuclear envelope.
Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly
A) the products of photosynthesis could not be metabolized without mitochondrial
B) all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do
not have plastids.
C) mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA.
D) without mitochondrial CO2 production, photosynthesis could not occur.
E) mitochondrial proteins are synthesized on cytosolic ribosomes, whereas plastids
utilize their own ribosomes.
Which group is incorrectly paired with its description?
A) rhizarians–morphologically diverse group defined by DNA similarities
B) diatoms–important producers in aquatic communities
C) red algae–acquired plastids by secondary endosymbiosis
D) apicomplexans–parasites with intricate life cycles
E) diplomonads–protists with modified mitochondria
Based on the phylogenetic tree in Figure 28.3 in the text, which of the following statements correct?
A) The most recent common ancestor of Excavata is older than that of Chromalveolata.
B) The most recent common ancestor of Chromalveolata is older than that of Rhizaria.
C) The most recent common ancestor of red algae and land plants is older than that of nucleariids and fungi.
D) The most basal (first to diverge) eukaryotic supergroup cannot be determined.
E) Excavata is the most basal eukaryotic supergroup
Which protists are in the same eukaryotic ʺ supergroupʺ as land plants?
A) green algae
C) red algae
D) brown algae
E) A and C are both correct
In life cycles with an alternation of generations, multicellular haploid forms alternate with
A) unicellular haploid forms.
B) unicellular diploid forms.
C) multicellular haploid forms.
D) multicellular diploid forms.
E) multicellular polyploid forms.
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