Deck 27: Protists

Question 1

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

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

Answer 1

B

Question 2

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 cause serious illness in humans.
B) They are not important to humans.
C) They are food for many marine organisms that humans eat.
D) They release a lot of carbon dioxide into the atmosphere.

Answer 2

C

Question 3

Use the following information to answer the corresponding questions).
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. T following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G. intestinalis 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.)
Figure 27.1
According to the phylogenetic tree in the figure above, Giardia intestinalis constitutes a _ group.

A) paraphyletic
B) polyphyletic
C) monophyletic

Answer 3

A

Question 4

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

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

Question 5

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

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

Question 6

Which of the following characteristics is true of all protists?

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

Question 7

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 mechanics of movement and protein structure are the same in these flagella, but there are significant genetic differences.
B) Both flagella are made of the same protein, but the configuration is different.
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 8

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

Question 9

Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in

A) their mode of nutrition.
B) whether they have a nucleus.
C) the way that they generate ATP.
D) their electron acceptors.
E) their sources of energy.

Question 10

Which of the following protists causes the human disease malaria?

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

Question 11

The microsporidian Brachiola gambiae parasitizes the mosquito Anopheles gambiae. Adult female mosquitoes must take blood meals for their eggs to develop, and it is while they take blood that they transmit malarial parasites to humans. Male mosquitoes drink flower nectar. If humans are to safely and effectively use Brachiola gambiae as
A biological control to reduce human deaths from malaria, then how many of the following statements should be
1) Brachiola should kill the mosquitoes before the malarial parasite they carry reaches maturity.
2) The microsporidian should not be harmful to other insects.
3) Microsporidians should infect mosquito larvae, rather than mosquito adults.
4) The subsequent decline in anopheline mosquitoes should not significantly disrupt human food resources or food webs.
5) Brachiola must be harmful to male mosquitoes but not to female mosquitoes.

A) 2 and 5
B) 3 and 4
C) 2, 3, 5
D) 1, 2, 3, and 4
E) 1, 2, and 4

Question 12

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

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

Question 13

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

A) It should not be labeled a species distinct from G. intestinalis.
B) It is part of a monophyletic group that also includes G. intestinalis.
C) It evolved before G. intestinalis.
D) It is more closely related to G. muris than to G. intestinalis.
E) None of the above can be concluded from the data provided.

Question 14

Figure 27.2

-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 evolved once; thus, animals are derived from the most recently evolved protists.
B) Multicellularity is a synapomorphy that defines a eukaryote.
C) Multicellularity evolved multiple times as eukaryotes diversified.
D) Multicellularity is more adaptive than unicellularity.
E) None of the above answers apply.

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

Question 16

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

Question 17

According to the endosymbiosis theory of the origin of eukaryotic cells, how did mitochondria originate?

A) through viral infection
B) from infoldings of the plasma membrane, coupled with mutations of genes for proteins in energy- transfer reactions
C) from engulfed, originally free- living proteobacteria
D) by secondary endosymbiosis
E) from the nuclear envelope folding outward and forming mitochondrial membranes

Question 18

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

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

Question 19

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

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

Question 20

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

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

Question 21

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

Question 22

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 23

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

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

Question 24

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) an apicomplexan
B) a dinoflagellata
C) a ciliate
D) a water mould
E) a euglenid

Question 25

How was primary productivity measured in the phytoplankton experiment?

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

Question 26

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

Question 27

The data graphed in Figure 27.3 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) There were still a small percentage of motile cells in the culture treated with the toxin.
B) When the toxin was washed off the culture, the cells began to move again.
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

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

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

Question 29

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) spherical thylakoids within their chloroplasts
D) flagella that beat in a circle
E) perfectly round lysosomes

Question 30

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

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

Question 31

Use the following information when answering the corresponding questions).
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, p the study described below, no one had provided convincing data that actin and myosin were actually involved in cell crawlin protists. Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in severa 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 Cytoskeleto 1999):23- 22), researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin.
Figure 27.3
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 data in the bar graph above?

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

Question 32

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

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

Question 33

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

Question 34

In examining a protist, you notice that it lacks a cell wall and has movement with cytoplasmic streaming. These data allow you to infer that the species belongs to which of the following protist groups?

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

Question 35

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

Question 36

What is the major distinguishing feature of Amoebozoa?

A) Cells have pronounced "feeding grooves" for digesting prey or organic debris.
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 chloroplasts with a double membrane.