Deck 29: Protists

Question 1

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

A)Photosynthetic protists give off a lot of carbon dioxide,and fertilizing them would increase carbon dioxide levels in the atmosphere.
B)Photosynthetic protists fix atmospheric carbon dioxide,decreasing carbon dioxide levels in the atmosphere.
C)Photosynthetic protists use a lot of oxygen,and fertilizing them would decrease oxygen levels in the environment.
D)Photosynthetic protists would release a lot of oxygen,and fertilizing them would increase levels of oxygen in the atmosphere.

Answer 1

B

Question 2

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. (T. Monis et al. 1999. Molecular systematics of the parasitic protozoan Giardia intestinalis. Mol. Biol. Evol. 16[9]:1135-44.)

According to the phylogenetic tree in the figure above,Giardia intestinalis constitutes a ________ group.

A)paraphyletic
B)monophyletic
C)polyphyletic

Answer 2

A

Question 3

By examining the phylogenetic tree diagrammed above,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.
E)None of the above can be concluded from the data provided.

Answer 3

D

Question 4

You isolate a previously undescribed protist species from the soil outside your residence.Which of the following technique(s)would provide useful data for describing,classifying,and naming this new species?

A)PCR
B)light microscopy
C)gene sequence comparison
D)electron microscopy
E)all of the above

Question 5

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 6

Which of the following would be considered a carbon sink that could potentially reduce atmospheric carbon dioxide to help alleviate global warming?

A)calcium carbonate
B)petroleum
C)sedimentary rocks
D)all of the above

Question 7

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 8

Figure 29.2
Refer to the figure above 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.
E)None of the above answers apply.

Question 9

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 10

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 11

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

A)The common ancestor of all 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.
E)All of the above answers apply.

Question 12

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)Both flagella 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.

Question 13

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.

Question 14

Which of the following protists causes the human disease malaria?

A)Giardia
B)Plasmodium
C)Trichomonas
D)Leishmania

Question 15

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 16

How are algal blooms (red tides)typically harmful to humans?

A)The blooms destroy shellfish and other food sources for humans.
B)Shellfish eat the harmful algae,and humans eat the contaminated shellfish.
C)Humans can become poisoned when swimming in contaminated water.
D)All of the above answers apply.

Question 17

Phytoplankton is comprised of photosynthetic protists and bacteria.For the most part,humans do not consume phytoplankton.Why,then,are they important 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 cause serious illness in humans.
D)They are not important to humans.

Question 18

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

Question 19

The structure of protist flagella indicates that this structure evolved directly from the bacterial flagella.

A)true
B)false

Question 20

Which of the following movements are matched correctly with the appendage that facilitates that movement in protists?

A)cell crawling;flagella
B)swimming;pseudopodia
C)cell crawling;cilia
D)swimming;flagella

Question 21

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

A)cosmetics
B)filters
C)chalk
D)marble
E)all of the above

Question 22

You discover a new lineage of protists.You examine several species of this lineage under the microscope and find a distinctive feature that sets them apart from other protists.Following the nomenclature style used to name the lineage Discicristata,you decide to name this new lineage Spherocristata.What is the distinctive feature that is reflected in the name?

A)a perfectly round nucleus
B)spherical cristae within their mitochondria
C)flagella that beat in a circle
D)spherical thylakoids within their chloroplasts
E)perfectly round lysosomes

Question 23

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.

Question 24

What is the major distinguishing feature of Amoebozoa?

A)Cells have chloroplasts with a double membrane.
B)Cells lack cell walls and so,when portions of the cell extend for movement,large lobes are formed.
C) Cells lack cell walls and so,when portions of the cell extend for movement,they are slender in shape.
D)Cells have pronounced "feeding grooves" for digesting prey or organic debris.

Question 25

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 26

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 27

Which of the major lineages of eukaryotes contain pronounced "feeding grooves" for digesting prey or organic debris?

A)Plantae
B)Excavata
C)Alveotata
D)Rhizaria

Question 28

How was primary productivity measured in the phytoplankton experiment?

A)net CO₂ uptake
B)the number of cells produced
C)net CO₂ production
D)accumulation of mutations

Question 29

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 data in the bar graph presented below?

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 30

Which of the following best describes what scientists (the Bell research group)concluded about the effect of atmospheric CO₂ increases on phytoplankton's primary productivity?

A)After 1000 generations,phytoplankton showed a consistent significant increase in primary productivity.
B)After 1000 generations,phytoplankton showed a consistent significant decrease in primary productivity.
C)After 1000 generations,phytoplankton showed a moderate increase in primary productivity.
D)After 1000 generations,phytoplankton will not show an increase in primary productivity.

Question 31

Alternation of generations occurs in 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 32

What is meant by the term "high-selected" lines in the phytoplankton experiment?

A)lines of phyloplankton that had strong environmental selection pressures
B)lines of phytoplankton that were grown in high CO₂ conditions,compared to other phytoplankton lines
C)lines of phytoplankton that were allowed to grow at a faster rate than other lines of phytoplankton
D)All of the above.
E)Both A and B.

Question 33

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 34

Cultures of the same species of diatom referred to in the previous question 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 35

The dinoflagellate Pfiesteria piscicida can feed off algae and bacteria.They can also "steal" intact chloroplasts from algae and become photosynthetic.In the presence of large amounts of fish,Pfiesteria can secrete a toxin that kills fish,allowing it to feed on decaying fish matter.How would you classify this species?

A)predator
B)primary producer
C)detritivore
D)all of the above
E)A and C only

Question 36

Protists belong to the domain Eukarya.Which of the following is not a protist?

A)kelp
B)red algae
C)yeast
D)diatoms