Question 1

Use the following information to answer the question.
Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gather at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1)if kept in darkness, the algae will die; and (2)if prey items (mostly bacteria)are absent from its habitat, P. bursaria will digest its zoochlorellae.
Which process in Paramecium results in genetic recombination but no increase in population size?
A) budding
B) meiotic division
C) conjugation
D) binary fission

Accepted Answer

Conjugation is the process of genetic recombination in Paramecium, but it does not result in an increase in population size. Binary fission and budding result in an increase in population size, while meiotic division is not a process that occurs in Paramecium.

Question 2

A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. This alga is most likely a type of ________.
A) red algae
B) brown algae
C) green algae
D) golden algae

Accepted Answer

Red algae are known to have adaptations that allow them to live at great depths where only blue light penetrates. They also have multicellular body plans and are commonly found in marine environments. Brown, green, and golden algae do not have specific adaptations for living at great depths.

Question 3

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, the taxon would ________.
A) be polyphyletic
B) be paraphyletic
C) be monophyletic
D) include all eukaryotes

Accepted Answer

A taxon that includes all organisms that have cells with pseudopods would be polyphyletic, as these organisms have evolved the feature independently and are not all descended from a common ancestor that had pseudopods.

Question 4

Including the membrane of the surrounding vesicle, how many phospholipid (not lipopolysaccharide)bilayers should be found around each P. chromatophora's chromatophore, and which one of these bilayers should have photosystems embedded in it?
A) two; innermost
B) two; outermost
C) three; innermost
D) three; outermost

Accepted Answer

The answer of Including the membrane of the surrounding vesicle,...

Question 5

Predict the most likely outcome of fertilizing areas of ocean with iron.
A) an increase in dinoflagellate populations that will eliminate problems caused by red tides
B) an increase in foram populations that will contribute to growth of corals and their symbionts
C) an increase in diatom populations that will contribute to reducing atmospheric CO₂
D) a decrease in slime mold populations and thus a decrease in decomposition rates

Accepted Answer

Fertilizing areas of ocean with iron can stimulate the growth of diatoms, which are primary producers that contribute to reducing atmospheric CO₂ through photosynthesis and sinking of organic matter to the deep ocean. It is important to note, however, that the potential consequences and trade-offs of ocean fertilization are complex and not fully understood.

Question 6

Previously recognized similarities that seemed to connect slime molds and fungi are now considered to be ________.
A) homologies
B) examples of convergent evolution
C) variations of common ancestral traits
D) adaptations for much different functions

Accepted Answer

Previously recognized similarities between slime molds and fungi were due to convergent evolution, not homologies or variations of common ancestral traits. The two groups have very different evolutionary histories and adaptations.

Question 7

Many chlorophytes are unicellular, but others are bigger and more complex. The fact that increased size and complexity evolved in different ways indicates ________.
A) the chlorophyte group is not monophyletic
B) the chlorophyte group is monophyletic
C) the chlorophyte group is the protist group most closely related to plants
D) the chlorophyte group contained extensive genetic variability

Accepted Answer

The answer of Many chlorophytes are unicellular, but others are...

Question 8

Use the following information to answer the question(s)below.
Paulinella chromatophora is one of the few cercozoans that is autotrophic, carrying out aerobic photosynthesis with its two elongated "chromatophores." The chromatophores are contained within vesicles of the host cell, and each is derived from a cyanobacterium, though not the same type of cyanobacterium that gave rise to the chloroplasts of algae and plants.
P. chromatophora secretes around itself a test, or case, of plates made of silica. Which of the following is another rhizarian that would be in competition with P. chromatophora for the silica needed to make these plates, assuming limited quantities of silica in the environment?
A) radiolarians
B) foraminiferans
C) dinoflagellates
D) diatoms

Accepted Answer

The answer of Use the following information to answer the...

Question 9

________ is an important group of protists that produce ________, a substance useful to humans.
A) Forams; diatomaceous earth
B) Dinoflagellates; red tide compounds
C) Diatoms; enzymes that digest cellulose
D) Kelp; algin

Accepted Answer

The answer of ________ is an important group of protists...

Question 10

SAR is a group defined by DNA similarities. This grouping represents ________.
A) a paraphyletic group
B) a hypothesis about evolutionary history
C) a catch-all group that links many unrelated organisms
D) a demonstration that DNA similarities cannot reveal evolutionary history

Accepted Answer

SAR is a group defined by DNA similarities, but it is not a catch-all group that links unrelated organisms. It is also not a demonstration that DNA similarities cannot reveal evolutionary history. Instead, SAR represents a hypothesis about evolutionary history based on DNA similarities, making it a monophyletic group. However, it is important to note that this hypothesis may be revised or corrected as new information becomes available.

Question 11

Evidence that supports placing green algae and plants in the same phylogenetic group includes ________.
A) similarities in mitochondrial structure and enzyme sequences
B) similarities in chloroplast structure and pigment composition
C) similarities in cell wall and membrane structure
D) DNA sequence similarities in genes for ribosome structure

Accepted Answer

Green algae and plants both contain chloroplasts with similar structure and pigments, supporting the idea that they evolved from a common ancestor. The other options may also show similarities but do not specifically support the grouping of green algae and plants together.

Question 12

Green algae differ from land plants in that many green algae ________.
A) are unicellular
B) have plastids
C) have alternation of generations
D) have cell walls containing cellulose

Accepted Answer

While some green algae are multicellular, many species are unicellular and this is a significant difference from land plants. Land plants are almost exclusively multicellular organisms.

Question 13

The genome of modern chloroplasts is roughly 50% the size of the genome of the cyanobacterium from which it is thought to have been derived. In comparison, the genome of P. chromatophora's chromatophore is only slightly reduced relative to the size of the genome of the cyanobacterium from which it is thought to have been derived. What is a valid hypothesis that can be drawn from this comparison?
A) Lytic phage infections have targeted the chloroplast genome more often than the P. chromatophora genome.
B) P. chromatophora's chromatophore is the result of an evolutionarily recent endosymbiosis.
C) The genome of the chloroplast ancestor contained many more introns that could be lost without harm compared to the chromatophore's genome.
D) The genome of the cyanobacteria was smaller than the genome of P. chromatophora.

Accepted Answer

The fact that the genome of P. chromatophora's chromatophore is only slightly reduced relative to the size of the genome of the cyanobacterium from which it is thought to have been derived suggests that the evolution of this endosymbiotic relationship occurred more recently than the evolution of the chloroplast. This supports the hypothesis that P. chromatophora's chromatophore is the result of an evolutionarily recent endosymbiosis.

Question 14

You are given the task of designing an aerobic, mixotrophic protist that can perform photosynthesis in fairly deep water (for example, 250 meters deep)and can also crawl about and engulf small particles. With which two of the following structures would you provide your protist?
A) hydrogenosomes and apicoplasts
B) apicoplasts and pseudopods
C) pseudopods and chloroplasts from red algae
D) chloroplasts from both red and green algae

Accepted Answer

Pseudopods allow the protist to crawl and engulf small particles, while chloroplasts from red algae would allow for photosynthesis in deeper water where green light has been filtered out. Hydrogenosomes and apicoplasts are unrelated to these functions, and having chloroplasts from both red and green algae may not be necessary for the specific conditions described.

Question 15

The fact that amoebas are not monophyletic demonstrates that ________.
A) movement by pseudopodia evolved only once
B) scientists need to continue to investigate the origins and evolutionary history of protists
C) evolutionary history cannot be discovered
D) eukaryotes are also not monophyletic and need to be broken into many groups

Accepted Answer

The fact that amoebas are not monophyletic indicates that the current understanding of protist evolution may not be complete, and that more research and investigation is needed to understand their evolutionary history.

Question 16

Use the following information to answer the question.
The mechanism of cell crawling in protist species is not well defined. Pseudopodia extension involves interactions between actin and myosin (the same molecules that are involved in vertebrate 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 the figure above. 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.
D) BDM will significantly increase motility of the cells in their natural habitats.

Accepted Answer

If an actin-myosin interaction is necessary for motility and BDM inhibits myosin function, then treating the cells with BDM should decrease motility. Therefore, the prediction that BDM will significantly decrease motility of the cells in culture is consistent with the hypothesis.

Question 17

Which of the following results would be most important in determining whether P. chromatophora's chromatophore is still an endosymbiont, or is an organelle, as the term chromatophore implies?
A) if P. chromatophora is less fit without its chromatophore than with it
B) if the chromatophore is less fit without the host cercozoan than with it
C) if there is ongoing metabolic cooperation between the chromatophore and the host cercozoan
D) if there has been movement of genes from the chromatophore genome to the nuclear genome, such that these genes are no longer present in the chromatophore genome

Accepted Answer

If genes have moved from the chromatophore genome to the nuclear genome, it suggests a level of integration between the two organisms that is more typical of organelles than endosymbionts. The other options are important in understanding the relationship between the host and the chromatophore, but do not provide as direct evidence of whether the chromatophore is an endosymbiont or an organelle.

Question 18

Use the following information to answer the question.
The mechanism of cell crawling in protist species is not well defined. Pseudopodia extension involves interactions between actin and myosin (the same molecules that are involved in vertebrate 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 the figure above. The data graphed in the figure could be an artifact if latrunculin A kills this species of diatoms (that is, 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 was 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.

Accepted Answer

If washing off the toxin allows the cells to move again, it suggests that the cells were not killed by the toxin and that the lack of motility was due to the toxin's effects on actin-myosin interactions. Choice B could also be a possible answer, as it suggests that some cells are still able to move despite the presence of the toxin, indicating that the toxin may not be killing all of the cells. However, choice A is the stronger answer, as it directly addresses whether the toxin is killing the cells or not. Choices C and D are not relevant to the question of whether the toxin is killing the cells, so they can be eliminated.

Question 19

Which of the following groups is matched with a correct anatomical feature?
A) foraminifera → silicon-rich tests
B) dinoflagellata → holdfast
C) diatoms → tests made of cellulose
D) brown algae → blade

Accepted Answer

Brown algae are characterized by their unique anatomical features, including a blade, which is a leaf-like structure that assists in photosynthesis. The other options are incorrect matches to the listed groups.

Question 20

Use the following information to answer the question.
The mechanism of cell crawling in protist species is not well defined. Pseudopodia extension involves interactions between actin and myosin (the same molecules that are involved in vertebrate 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 the figure above. 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 conclusions 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.
D) In this species of diatom, fully formed myosin proteins are necessary for movement.

Accepted Answer

The answer of Use the following information to answer the...

Quiz 28: Protists

A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. This alga is most likely a type of ________.

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, the taxon would ________.

Including the membrane of the surrounding vesicle, how many phospholipid (not lipopolysaccharide) bilayers should be found around each P. chromatophora's chromatophore, and which one of these bilayers should have photosystems embedded in it?

Predict the most likely outcome of fertilizing areas of ocean with iron.

Previously recognized similarities that seemed to connect slime molds and fungi are now considered to be ________.

Many chlorophytes are unicellular, but others are bigger and more complex. The fact that increased size and complexity evolved in different ways indicates ________.

is an important group of protists that produce , a substance useful to humans.

SAR is a group defined by DNA similarities. This grouping represents ________.

Evidence that supports placing green algae and plants in the same phylogenetic group includes ________.

Green algae differ from land plants in that many green algae ________.

You are given the task of designing an aerobic, mixotrophic protist that can perform photosynthesis in fairly deep water (for example, 250 meters deep) and can also crawl about and engulf small particles. With which two of the following structures would you provide your protist?

The fact that amoebas are not monophyletic demonstrates that ________.

Which of the following results would be most important in determining whether P. chromatophora's chromatophore is still an endosymbiont, or is an organelle, as the term chromatophore implies?

Which of the following groups is matched with a correct anatomical feature?