bio 2 ch 28
see student edition questions 6)
6
see word document
66
1) 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 adenosine triphosphate (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.
A
13) Use the following information to answer the question. Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine's lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host's intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. Infection usually occurs by drinking untreated water that contains cysts. Given its mode of reproduction and internal structures, which of the following should be expected to occur in Giardia at some stage of its life cycle? A) separation (segregation) of daughter chromosomes B) crossing over C) meiosis D) synapsis
A
15) Trypanosome infections evade attacks by host immune systems through which of the following mechanisms? A) production of new cell-surface proteins with a different molecular structure by each new generation B) production of toxins that kill lymphocytes C) insertion of its DNA into the nuclear DNA of host cells D) infection of lymphocytes leading to a decline in the host's ability to fight infection
A
19) Which two genera have members that can evade the human immune system by frequently changing their surface proteins? A) Plasmodium and Trypanosoma B) Trichomonas and Paramecium C) Trichomonas and Trypanosoma D) Trypanosoma and Entamoeba
A
2) The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence? A) cyanobacteria → green algae → land plants B) cyanobacteria → green algae → fungi → land plants C) red algae → brown algae → green algae → land plants D) cyanobacteria → red algae → green algae → land plants
A
20) Which of the following pairs of protists and their ecological roles are correctly matched? A) apicomplexans—parasites of animals B) euglenozoans—primarily mixotrophic C) dinoflagellates—parasites of plants D) entamoebas—free-living soil organisms
A
26) Reinforced, threadlike pseudopods that can perform phagocytosis are generally characteristic of ________. A) foramifera B) water molds C) dinoflagellates D) oomycetes
A
28) 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) ________. A) diatom B) dinoflagellate C) apicomplexan D) red alga
A
31) You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. When light, especially red and blue light, is shone on the tubes, oxygen bubbles accumulate on the inside of test tubes 1 and 2. Chemical analysis of test tube 1 indicates the presence of a chemical that is toxic to fish and humans. Chemical analysis of test tube 2 indicates the presence of substantial amounts of silica. Microscopic analysis of organisms in test tubes 1, 3, and 4 reveals the presence of permanent, membrane-bounded sacs just under the plasma membrane. Microscopic analysis of organisms in test tube 3 reveals the presence of an apicoplast in each. Microscopic analysis of the contents in test tube 4 reveals the presence of one large nucleus and one small nucleus in each organism. Test tube 4 contains ________. A) Paramecium B) Pfiesteria (dinoflagellate) C) Entamoeba D) Plasmodium
A
36) 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 term best describes the symbiotic relationship of well-fed P. bursaria to their zoochlorellae? A) mutualistic B) parasitic C) predatory D) pathogenic
A
43) 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.
A
44) 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.
A
45) 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 Answer: A Bloom's Taxonomy: Knowledge/Comprehension Section: 28.3
A
46) 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
A
49) 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
A
54) 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
A
56) 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
A
63) Which of the following is responsible for nearly 100,000 human deaths worldwide every year? A) Entamoeba histolytica B) Amoeba proteus C) plasmodial slime molds D) Dictyostelium discoideum
A
Dinoflagellates A) possess two flagella B) are all autotrophic C) lack mitochondria D) include species that cause malaria
A
17) Prokaryotic and eukaryotic flagella ________. A) have the same evolutionary origin B) have different structures C) require different sources of energy D) contain their own DNA
B
18) When a mosquito infected with Plasmodium first bites a human, the Plasmodium ________. A) gametes fuse, forming an oocyst B) cells infect the human liver cells C) cells cause lysing of the human red blood cells D) oocyst undergoes meiosis
B
23) Which of the following is characteristic of ciliates? A) They use pseudopods as feeding structures. B) They are often multinucleate. C) They can exchange genetic material with other ciliates by the process of mitosis. D) Most live as solitary autotrophs in fresh water.
B
24) 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 do diatoms get transported from one location on the water's surface layers to another location on the surface? B) How do diatoms with their glasslike valves keep from sinking into poorly lit waters? C) How do diatoms with their glasslike valves avoid being shattered by the action of waves? D) How do diatom sperm cells locate diatom egg cells?
B
25) A large seaweed that floats freely on the surface of deep bodies of water would be expected to have which of the following? A) rigid stems B) bladders C) true roots D) gel-forming proteins
B
27) A porous test (shell) of calcium carbonate, through which pseudopodia protrude, is characteristic of ________. A) diatoms B) foraminiferans C) ciliates D) water molds
B
3) Which group is incorrectly paired with its description? A) diatoms—important producers in aquatic communities B) red algae—eukaryotes that acquired plastids by secondary endosymbiosis C) apicomplexans—unicellular parasites with intricate life cycles D) diplomonads—unicellular eukaryotes with modified mitochondria
B
32) You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. When light, especially red and blue light, is shone on the tubes, oxygen bubbles accumulate on the inside of test tubes 1 and 2. Chemical analysis of test tube 1 indicates the presence of a chemical that is toxic to fish and humans. Chemical analysis of test tube 2 indicates the presence of substantial amounts of silica. Microscopic analysis of organisms in test tubes 1, 3, and 4 reveals the presence of permanent, membrane-bounded sacs just under the plasma membrane. Microscopic analysis of organisms in test tube 3 reveals the presence of an apicoplast in each. Microscopic analysis of the contents in test tube 4 reveals the presence of one large nucleus and one small nucleus in each organism. Test tube 1 contains ________. A) Paramecium B) Pfiesteria (dinoflagellate) C) Entamoeba D) Plasmodium
B
38) 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. A P. bursaria cell that has lost its zoochlorellae is said to be aposymbiotic. It might be able to replenish its contingent of zoochlorellae by ingesting them without subsequently digesting them. Which of the following situations would be most favorable to the reestablishment of resident zoochlorellae, assuming compatible Chlorella are present in P. bursaria's habitat? A) abundant light, no bacterial prey B) abundant light, abundant bacterial prey C) no light, no bacterial prey D) no light, abundant bacterial prey
B
39) A P. bursaria cell that has lost its zoochlorellae is aposymbiotic. If aposymbiotic cells have population growth rates the same as those of healthy, zoochlorella-containing P. bursaria in well-lit environments with plenty of prey items, then such an observation would be consistent with which type of relationship? A) parasitic B) competitive C) toxic D) mutualistic
B
4) All protists are ________. A) unicellular B) eukaryotic C) symbionts D) mixotrophic
B
48) 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.
B
51) 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
B
52) 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
B
58) 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
B
60) 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
B
62) Super cells characteristic of plasmodial slime molds result when which one of the following common cellular processes does not occur? A) mitosis B) cytokinesis C) aerobic metabolism D) endocytosis
B
67) Imagine 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
B
69) Living diatoms contain brownish plastids. If global warming causes blooms of diatoms in the surface waters of Earth's oceans, how might this be harmful to the animals that build coral reefs? A) The coral animals, which capture planktonic organisms, may be outcompeted by the diatoms. B) The coral animals' endosymbiotic dinoflagellates may get "shaded out" by the diatoms. C) The coral animals may die from overeating the plentiful diatoms with their cases of silica. D) The diatoms' photosynthetic output may over-oxygenate the water.
B
7) Use the following information to answer the question. 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. The closest living relative of P. chromatophora is the heterotroph P. ovalis. P. ovalis uses threadlike pseudopods to capture its prey, which it digests internally. Which of the following, if observed, would be the best reason for relabeling P. chromatophora as a mixotroph instead of an autotroph? A) a pigmented central vacuole, surrounded by a nucleomorph B) a vacuole with food inside C) a secretory vesicle D) a contractile vacuole
B
72) Which of the following statements is accurate with regard to the observation that "income levels in countries hard hit by malaria are 33% lower than in similar countries free of the disease." A) This observation suggests that symptoms from malaria cause patients to lose pay because they miss work. B) This observation is an example of a correlation and therefore causality cannot be inferred as confidently as if we have results from a manipulated experiment. C) In order to understand the cause of this observation, scientists should eradicate malaria in ten countries but not in ten other comparable countries in order to experimentally test whether malaria caused the low income levels. D) The observation demonstrates that correlations provide excellent indications of causality.
B
75) Biologists think that endosymbiosis gave rise to mitochondria before plastids partly because A) the products of photosynthesis could not be metabolized without mitochondrial enzymes. 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.
B
8) Use the following information to answer the question. 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. Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without the net loss of any genetic information? A) conjugation B) horizontal gene transfer C) phagocytosis D) meiosis
B
10) 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? The first eukaryote may have been ________. A) very similar to a plant cell B) anaerobic C) capable of phagocytosis D) photosynthetic
C
11) Use the following information to answer the question. Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine's lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host's intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. Infection usually occurs by drinking untreated water that contains cysts. Giardia's mitosome can be said to be "doubly degenerate," because it is a degenerate type of ________, an organelle that is itself a degenerate form of ________. A) nucleus; archaean B) nucleus; bacterium C) mitochondria; proteobacterium D) mitochondria; spirochete
C
14) Use the following information to answer the question. Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine's lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host's intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. Infection usually occurs by drinking untreated water that contains cysts. If the mitosomes of Giardia contain no DNA, yet are descendants of what were once free-living organisms, then where are we likely to find the genes that encode their structures, and what accounts for their current location there? A) plasmids; conjugation B) plasmids; transformation C) nucleus; horizontal gene transfer D) nucleus; S phase
C
16) Many parasitic members of the excavates lack plastids and have highly reduced mitochondria. Which of the following statements explains these observations? A) These parasites live in dark, low-oxygen conditions, and therefore it was adaptive to move all plastid and mitochondrial genes to the nucleus. B) The original, eukaryotic ancestors of these parasites did not engulf prokaryotes. C) These parasites live in dark, low-oxygen conditions and therefore loss of genes for plastids and mitochondria did not result in lower fitness. D) In the future, natural selection will favor descendants that acquire new plastid genes from today's prokaryotes
C
22) 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 two nuclei, one large and one small. This organism is most likely to be a ________. A) foraminiferan B) radiolarian C) ciliate D) kinetoplastid
C
29) A gelatinous seaweed that grows in shallow, cold water and undergoes heteromorphic alternation of generations is most probably what type of alga? A) red B) green C) brown D) yellow
C
3) A particular species of protist has obtained a chloroplast via secondary endosymbiosis. You know this because the chloroplasts ________. A) have nuclear and cyanobacterial genes B) are exceptionally small C) have three or four membranes D) have only a single pigment
C
34) Use the following description and table to answer the question. Diatoms are encased in petri-plate-like cases (valves) made of translucent hydrated silica whose thickness can be varied. The material used to store excess calories can also be varied. At certain times, diatoms store excess calories in the form of the liquid polysaccharide, laminarin, and at other times as oil. The following are data concerning the density (specific gravity) of various components of diatoms, and of their environment. Specific Gravities of Materials Relevant to Diatoms Material Specific Gravity (kg/m3) Pure water 1000 Seawater 1026 Hydrated silica 2250 Liquid laminarin 1500 Diatom oil 910 Water's density and, consequently, its buoyancy decrease at warmer temperatures. Based on this consideration, and using data from the table above, at which time of year should one expect diatoms to be storing excess calories mostly as oil? A) mid-winter B) early spring C) late summer D) late fall
C
35) Use the following description and table to answer the question. Diatoms are encased in petri-plate-like cases (valves) made of translucent hydrated silica whose thickness can be varied. The material used to store excess calories can also be varied. At certain times, diatoms store excess calories in the form of the liquid polysaccharide, laminarin, and at other times as oil. The following are data concerning the density (specific gravity) of various components of diatoms, and of their environment. Specific Gravities of Materials Relevant to Diatoms Material Specific Gravity (kg/m3) Pure water 1000 Seawater 1026 Hydrated silica 2250 Liquid laminarin 1500 Diatom oil 910 Water's density and, consequently, its buoyancy decrease at warmer temperatures. Considering the impact of temperature, and the table above, in which environment should diatoms sinking be slowest? A) cold fresh water B) warm fresh water C) cold seawater D) warm seawater
C
37) 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. The motility that permits P. bursaria to move toward a light source is provided by ________. A) pseudopods B) a single flagellum featuring the 9 + 2 pattern C) many cilia D) contractile vacuoles
C
40) 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. Theoretically, P. bursaria can obtain zoochlorellae either vertically (via the asexual reproduction of its mother cell) or horizontally (by ingesting free-living Chlorella from its habitat). Consider a P. bursaria cell containing zoochlorellae but whose habitat lacks free-living Chlorella. If this cell subsequently undergoes many generations of asexual reproduction, if all of its daughter cells contain roughly the same number of zoochlorellae as it had originally contained, and if the zoochlorellae are all haploid and identical in appearance, then which statement is accurate? The zoochlorellae ________. A) also reproduced asexually, at an increasing rate over time B) also reproduced asexually, at a decreasing rate over time C) also reproduced asexually, at a fairly constant rate over time D) reproduced sexually, undergoing heteromorphic alternation of generations
C
41) 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
C
42) 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
C
5) 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.
C
53) 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
C
55) 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
C
65) Use the following figure to answer the question. "Rare events" can help us understand evolutionary events, as shown in the figure. Which of the following statements explains the logic of this approach? A) Organisms with the mutation evolved convergently. B) The mutation provided an adaptive advantage to the organisms that contained it. C) Because the mutation likely occurred only once, all organisms with the mutation have a common ancestor with the mutation. D) "Reverse evolution" does not occur.
C
70) Which of the following organisms is a producer? A) kinetoplastids B) apicomplexans C) diatoms D) ciliates
C
71) Which of the following approaches would be most likely to cause evolution of a drug-resistant strain of Plasmodium? A) widespread, frequent spraying to kill mosquitoes B) use of a cocktail of three drugs in patients suffering from malaria C) widespread, frequent use of a single drug in patients suffering from malaria D) widespread use of anti-mosquito bed nets
C
73) Which of the following results would be most likely if a layer of warm, light water caused by ocean surface warming blocks nutrient upwelling? A) reduced populations of fish because they avoid warm water B) increased populations of producers because they have access to more CO2 C) reduced populations of producers because they have access to fewer nutrients D) increased populations of producers because fewer fish are produced, and they eat fewer producers
C
9) Use the following information to answer the question. Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine's lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host's intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. Infection usually occurs by drinking untreated water that contains cysts. The cysts of Giardia function most like the ________. A) mitochondria of ancestral diplomonads B) nuclei of archaeans C) endospores of bacteria D) capsids of viruses
C
12) Use the following information to answer the question. Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine's lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host's intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. Infection usually occurs by drinking untreated water that contains cysts. The mitosome of Giardia has no DNA within it. If it did contain DNA, then what predictions should we be able to make about its DNA? A) It is linear, has many introns, and is not associated with histone proteins. B) It is linear, has few introns, and is complexed with histone proteins. C) It is circular, has many introns, and is complexed with histone proteins. D) It is circular, has few introns, and is not associated with histone proteins.
D
30) You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. When light, especially red and blue light, is shone on the tubes, oxygen bubbles accumulate on the inside of test tubes 1 and 2. Chemical analysis of test tube 1 indicates the presence of a chemical that is toxic to fish and humans. Chemical analysis of test tube 2 indicates the presence of substantial amounts of silica. Microscopic analysis of organisms in test tubes 1, 3, and 4 reveals the presence of permanent, membrane-bounded sacs just under the plasma membrane. Microscopic analysis of organisms in test tube 3 reveals the presence of an apicoplast in each. Microscopic analysis of the contents in test tube 4 reveals the presence of one large nucleus and one small nucleus in each organism. Test tube 3 contains ________. A) Paramecium B) Pfiesteria (dinoflagellate) C) Entamoeba D) Plasmodium
D
33) You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. When light, especially red and blue light, is shone on the tubes, oxygen bubbles accumulate on the inside of test tubes 1 and 2. Chemical analysis of test tube 1 indicates the presence of a chemical that is toxic to fish and humans. Chemical analysis of test tube 2 indicates the presence of substantial amounts of silica. Microscopic analysis of organisms in test tubes 1, 3, and 4 reveals the presence of permanent, membrane-bounded sacs just under the plasma membrane. Microscopic analysis of organisms in test tube 3 reveals the presence of an apicoplast in each. Microscopic analysis of the contents in test tube 4 reveals the presence of one large nucleus and one small nucleus in each organism. Test tube 2 contains ________. A) Paramecium B) Pfiesteria (dinoflagellate) C) Entamoeba D) Triceratium (diatom)
D
4) According to the phylogeny presented in this chapter, which protists are in the same eukaryotic supergroup as plants? A) green algae B) dinoflagellates C) red algae D) both A and C
D
47) 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
D
5) In a life cycle with alternation of generations, multicellular haploid forms alternate with A) unicellular haploid forms. B) unicellular diploid forms. C) multicellular haploid forms. D) multicellular diploid forms.
D
50) ________ 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
D
57) 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
D
59) 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
D
6) Which of the following have chloroplasts (or structures since evolved from chloroplasts) thought to be derived from ancestral green algae? A) stramenopiles B) apicomplexans C) dinoflagellates D) chlorarachniophytes
D
61) Branching points at the root of the eukaryotic phylogenetic tree ________. A) reveal that unikonts are derived from the SAR clade B) suggest that Archaeplastids were the first eukaryotes C) strongly suggest that fungi are more closely related to plants than animals D) are presently unclear
D
64) In order to determine the "root" of the eukaryote phylogenetic tree, scientists should ________. A) compare the myosin genes in amoebozoans and opisthokonts B) compare the sequences of chloroplast genes of green algae and plants C) sequence more nuclear genes in green algae and plants D) sequence more nuclear genes in slime molds and other unikonts
D
68) 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 term most accurately describes the nutritional mode of healthy P. bursaria? A) photoautotroph B) photoheterotroph C) chemoautotroph D) mixotroph
D
74) 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.
D
