Deck 29: Protists

Question 1

A particular species of protist has obtained a chloroplast via secondary endosymbiosis.How can you tell?

A)The chloroplasts have both nuclear and cyanobacterial genes.
B)The chloroplasts are exceptionally small.
C)The chloroplasts have three or four membranes.
D)The chloroplasts have only a single pigment.

Answer 1

C

Question 2

Which of the following observations about flagella is true and is consistent with the scientific conclusion that the flagella from protists and bacteria evolved independently?

A)The flagella of both protists and bacteria are made of the same protein,but the configuration is different.
B)The mechanics of movement and protein structure are the same in these flagella,but there are significant genetic differences.
C)Although the mechanism of movement in both flagella is the same,the protein that accomplishes the movement is different.
D)The protein structure and the mechanism of movement in protist flagella are different from those of bacteria flagella.

Answer 2

D

Question 3

Which of the following statements is consistent with the assertion that protists are paraphyletic?

A)Some protists evolved into other eukaryotic groups.
B)Protists all share a common set of synapomorphies.
C)Protists are all more primitive than land plants and animals.
D)Protists do not share a single common ancestor.

Answer 3

A

Question 4

Plankton is comprised of photosynthetic protists and bacteria.What is the primary importance of plankton to humans?

A)They are food for many marine organisms that humans eat.
B)They release a lot of carbon dioxide into the atmosphere.
C)They contribute to the formation of anaerobic dead zones in the oceans.
D)They form the basic building blocks in the formation of petroleum (oil).

Question 5

You discover a new eukaryotic species.It is non-photosynthetic,unicellular,and its motile cells contain a single flagellum.To which group of eukaryotes might this organism belong?

A)Amoebozoa
B)Excavata
C)Rhizaria
D)Alveolata

Question 6

When a mosquito infected with Plasmodium first bites a human _____.

A)the Plasmodium gametes fuse,forming an oocyst
B)the Plasmodium cells infect the human liver cells
C)the Plasmodium cells cause lysing of the human red blood cells
D)the Plasmodium oocyst undergoes meiosis

Question 7

Which of the following statements best describes the term synapomorphy?

A)a trait that is shared by more than one monophyletic group
B)a trait common in a single monophyletic group,but not generally found outside of that group
C)the state of having several traits in common with different monophyletic groups
D)a trait that evolved in several different monophyletic groups simultaneously

Question 8

Which of the following is most likely to lead to PSP (paralytic shellfish poisoning)?

A)dinoflagellates
B)Giardia
C)Plasmodium
D)Toxoplasma
E)diatoms

Question 9

Imagine there are 25 different species of protists living in a tide pool.Some of these species reproduce both sexually and asexually,and some of them can reproduce only asexually.The pool gradually becomes infested with disease-causing viruses and bacteria.Which species are more likely to thrive in the changing environment?

A)the sexually reproducing species
B)the asexually reproducing species
C)Sexually and asexually reproducing species are equally likely to thrive.
D)cannot tell from this information - survival will depend on a variety of other factors

Question 10

Figure 29.1
Use the following information to answer the corresponding question(s).
Giardia intestinalis can cause disease in several different mammalian species,including humans.Giardia organisms (G.intestinalis)that infect humans are similar morphologically to those that infect other mammals;thus they have been considered a single species,though other species in the Giardia genus infect other organisms.However,G.intestinalis has been divided into different subgroups based on their host and a few other characteristics.
In 1999,a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species.The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G.intestinalis and a few other morphologically distinct species of Giardia.The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species.

By examining the phylogenetic tree diagrammed in Figure 29.1,what conclusion can you draw about the species G.microti?

A)It evolved before G.intestinalis.
B)It is more closely related to G.muris than to G.intestinalis.
C)It should not be labeled a species distinct from G.intestinalis.
D)It is part of a monophyletic group that also includes G.intestinalis.

Question 11

Figure 29.5

Which of the following might be a result of adding a secondary consumer (a species that feeds on primary consumers)to the aquatic ecosystem illustrated above?

A)a decrease in the number of primary consumers
B)a decrease in the population of decomposers
C)an increase in atmospheric CO₂
D)an increase in the population of scavengers
E)a decrease in the carbon sink

Question 12

Which of the following monophyletic eukaryotic clades includes photosynthetic species with double-membraned chloroplasts?

A)Bikonta
B)Unikonta
C)Opisthokonta
D)Chromalveolata

Question 13

Which of the following eukaryotic lineages contains species that all lack functioning mitochondria?

A)Excavata
B)Rhizaria
C)Amoebozoa
D)Stramenopila

Question 14

Encouraging the growth (via nutrient fertilization)of photosynthetic protists in marine environments may help reduce global warming.Why?

A)because photosynthetic protists form the base of many marine food chains
B)because photosynthetic protists fix atmospheric carbon dioxide,decreasing atmospheric CO₂ levels
C)because the increased oxygen consumption by large populations of photosynthetic protists will promote land plants to speed up photosynthesis,thus removing CO₂ from the atmosphere
D)because photosynthetic protists would release a lot of oxygen,and fertilizing them would increase levels of oxygen in the atmosphere

Question 15

A particular species of protist lacks the ability to engulf food and does not contain chloroplasts.However,gene sequencing data indicate that this species evolved from a lineage containing many species with the ability to engulf food.What does this information suggest about this species of protist?

A)It probably reproduces asexually.
B)It is likely parasitic.
C)It is likely aquatic.
D)It probably eats bacteria.

Question 16

Figure 29.2

Refer to Figure 29.2 and consider the following data:
Brown algae (protists)include unicellular and multicellular organisms.Red algae (protists)include unicellular and multicellular organisms.Amoebae (protists)include unicellular and multicellular organisms.Which of the following conclusions is consistent with the data presented?

A)Multicellularity is a synapomorphy that defines a eukaryote.
B)Multicellularity evolved once;thus,animals are derived from the most recently evolved protists.
C)Multicellularity evolved multiple times as eukaryotes diversified.
D)Multicellularity is more adaptive than unicellularity.

Question 17

In an area with a high abundance of algal blooms,the introduction of _____ might alleviate the severity of the blooms.

A)dinoflagellates
B)plankton
C)primary producers
D)copepods

Question 18

Which of the following characteristics is true of all protists?

A)contain a nucleus
B)smaller than animal cells
C)unicellular
D)have a cell wall
E)photosynthetic

Question 19

According to the endosymbiotic theory,why was it adaptive for the larger (host)cell to keep the engulfed cell alive,rather than digesting it as food?

A)The engulfed cell provided the host cell with ATP.
B)The engulfed cell provided the host cell with carbon dioxide.
C)The engulfed cell allowed the host cell to metabolize glucose.
D)The host cell was able to survive anaerobic conditions with the engulfed cell alive.
E)The host cell would have been poisoned if it had digested the engulfed cell.

Question 20

Figure 29.1
Use the following information to answer the corresponding question(s).
Giardia intestinalis can cause disease in several different mammalian species,including humans.Giardia organisms (G.intestinalis)that infect humans are similar morphologically to those that infect other mammals;thus they have been considered a single species,though other species in the Giardia genus infect other organisms.However,G.intestinalis has been divided into different subgroups based on their host and a few other characteristics.
In 1999,a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species.The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G.intestinalis and a few other morphologically distinct species of Giardia.The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species.

According to the phylogenetic tree in Figure 29.1,Giardia intestinalis constitutes a _____ group.

A)paraphyletic
B)monophyletic
C)polyphyletic

Question 21

What is necessary in order for symbiosis to occur?

A)one organism must benefit from associating with another organism
B)two organisms must live in regular physical contact with each other
C)one organism must ingest another organism
D)two organisms must be competing for the same resources

Question 22

One of the fish in your aquarium dies.Adding which protist to the water would allow you to avoid flushing the dead fish by speeding its decay?

A)Apicomplexa
B)Dinoflagellata
C)Oomycota
D)Ciliata
E)Myxogastrida

Question 23

The manufacture of which of the following products involves using materials that once belonged to a Phaetophyte?

A)cosmetics
B)filters
C)chalk
D)sushi
E)insecticides

Question 24

Which of the following groups is matched with an incorrect anatomical feature?

A)foraminifera → tests with holes
B)dinoflagellata → two flagella
C)oomycota → apical complex
D)diatoms → silicon-rich tests
E)phaeophyta → exclusively multicellular

Question 25

Assume that some members of an aquatic species of motile,photosynthetic protists evolve to become parasitic to fish.They gain the ability to live in the fish gut,absorbing nutrients as the fish digests food.Over time,which of the following phenotypic changes would you expect to observe in this population of protists?

A)loss of motility
B)loss of chloroplasts
C)gain of a rigid cell wall
D)gain of meiosis
E)no changes would be expected

Question 26

You discover a new species of protist.Which of the following characteristics would provide the strongest evidence for your hypothesis that your species belongs in Euglenida?

A)It is photosynthetic.
B)It contains the carbohydrate paramylon.
C)It reproduces asexually.
D)It is unicellular.
E)It lacks a cell wall.

Question 27

Figure 29.3
Use the following information when answering the corresponding question(s).
The mechanism of cell crawling in protist species is not well defined.The textbook states that pseudopodia extension involves interactions between actin and myosin (the same molecules that are involved in mammalian muscle contraction).However,prior to the study described below,no one had provided convincing data that actin and myosin were actually involved in cell crawling in protists.Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in several species of protist;but physiological studies had failed to show a functional link between actin,myosin,and cell crawling.
In a study by N.Poulsen et al.(Diatom gliding is the result of an actin-myosin motility system,Cell Motility and the Cytoskeleton 44 (1999):23-22),researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin.

Refer to the study by Poulsen et al.and Figure 29.3.The data graphed in Figure 29.3 could be an artifact if latrunculin A kills this species of diatoms (i.e. ,that may be why the cells are not moving).Which of the following would be the best evidence that latrunculin A is not killing the cells?

A)When the toxin was washed off the culture,the cells began to move again.
B)There were still a small percentage of motile cells in the culture treated with the toxin.
C)Most of the cells in the control were moving,indicating that they were alive.
D)When the toxin was applied to another species of diatom,25% of them continued to move.

Question 28

Figure 29.3
Use the following information when answering the corresponding question(s).
The mechanism of cell crawling in protist species is not well defined.The textbook states that pseudopodia extension involves interactions between actin and myosin (the same molecules that are involved in mammalian muscle contraction).However,prior to the study described below,no one had provided convincing data that actin and myosin were actually involved in cell crawling in protists.Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in several species of protist;but physiological studies had failed to show a functional link between actin,myosin,and cell crawling.
In a study by N.Poulsen et al.(Diatom gliding is the result of an actin-myosin motility system,Cell Motility and the Cytoskeleton 44 (1999):23-22),researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin.

Refer to the study by Poulsen et al.and Figure 29.3.Cultures of a species of diatom were treated with BDM,a reversible inhibitor of myosin function.Which of the following predictions is consistent with the hypothesis that an actin-myosin interaction is necessary for motility?

A)BDM will significantly decrease motility of the cells in culture.
B)BDM will not significantly alter motility of the cells in culture.
C)BDM will significantly increase motility of the cells in culture.

Question 29

In examining a multicellular protist,you notice that it uses pseudopods to engulf its food,that it reproduces asexually by mitosis,and that it has multiple nuclei.These data allow you to infer that the species belongs to which of the following protist groups?

A)Euglenida
B)Diatoms
C)Foraminifera
D)Diplomonadida
E)Parabasalida

Question 30

Alternation of generations occurs in some protists.Which of the following represents the correct sequence of events for this mode of reproduction?

A)gametophyte → gamete → fusion → sporophyte → spore → gametophyte
B)sporophyte → spore fusion → gametophyte → gamete → sporophyte
C)gametophyte → fusion → sporophyte → spore → gamete → gametophyte
D)gamete → fusion → gametophyte → spore → sporophyte → gamete

Question 31

Figure 29.3
Use the following information when answering the corresponding question(s).
The mechanism of cell crawling in protist species is not well defined.The textbook states that pseudopodia extension involves interactions between actin and myosin (the same molecules that are involved in mammalian muscle contraction).However,prior to the study described below,no one had provided convincing data that actin and myosin were actually involved in cell crawling in protists.Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in several species of protist;but physiological studies had failed to show a functional link between actin,myosin,and cell crawling.
In a study by N.Poulsen et al.(Diatom gliding is the result of an actin-myosin motility system,Cell Motility and the Cytoskeleton 44 (1999):23-22),researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin.

Refer to the study by Poulsen et al.and Figure 29.3.Latrunculin A is a reversible toxin that disrupts the formation of actin fibers.A culture of a particular species of diatom was treated with this toxin diluted in a buffer,while another culture was treated only with the buffer (no toxin;control).The motility of cells in each culture was assessed by counting the number of cells that were moving during a defined period of time.Which of the following conclusion statements is reasonable based on the above figure?

A)Formation of actin fibers is not necessary for the movement in this species of diatom.
B)The buffer alone largely inhibited movement in this species of diatom.
C)In this species of diatom,fully formed actin fibers are necessary for movement.

Question 32

Consider the following data:
(a)Most ancient eukaryotes are unicellular.(b)All eukaryotes alive today have a nucleus and cytoskeleton.(c)Most ancient eukaryotes lack a cell wall.Which of the following conclusions could reasonably follow the data presented?

A)The first eukaryote may have been very similar to a plant cell.
B)The first eukaryote may have been anaerobic.
C)The first eukaryote may have been capable of phagocytosis.
D)The first eukaryote may have been photosynthetic.

Question 33

Which of the following protist lineages is appropriately paired with its supportive and/or protective structure?

A)Diatoms have an intricate,chalky,chambered calcium carbonate shell.
B)Parabasalids have an internal support rod,made of cross-linked microtubules,that runs the length of the cell.
C)Alveolates have tough plates in the cell wall that are made up of cellulose.
D)Euglenoids cover themselves with tiny pebbles.
E)Dinoflagellates are surrounded by a glass-like,silicone dioxide cell wall.

Question 34

Consider the following points:
(a)All excavates live in environments where oxygen availability is low;(b)all excavates lack mitochondria;and (c)all excavates have some mitochondrial genes.Based on this information,which of the following statements is true of the excavate lineage?

A)Their ancestors were eukaryotes that existed prior to the origin of mitochondria.
B)Their ancestors had mitochondria,but the mitochondria were lost over time.
C)Their ancestors were not able to metabolize glucose.
D)Excavates are in the process of acquiring mitochondria through evolutionary adaptation.