EXAM 2 (ch28,29,30,31)
Evidence indicates that plants increase the number of stomata in their leaves as atmospheric CO2 levels decline. Increasing the number of stomata per unit surface area should have the effect of doing which of the following? 1.
increasing dehydration of leaf tissues 2. decreasing dehydration of leaf tissues 3. countering the effect of declining CO2 on photosynthesis 4. reinforcing the effect of declining CO2 on photosynthesis 5. decreasing the O2 content of air next to the leaves lower than it would otherwise be 6. increasing the O2 content of air next to the leaves higher than it would otherwise be B) 1, 3, and 6 Answer: B
A student encounters a pondweed which, judging from its appearance, seems to be a charophyte. She brings a sample back to her biology lab. Using only a compound light microscope to study the sample, which of the following features should help her to determine whether the sample comes from a charophyte or from some other type of green alga? 1.
molecular structure of enzymes inside peroxisomes 2. structure of sperm cells 3. presence of phragmoplasts 4. rings of cellulose-synthesizing complexes E) 2, 3, and 4 Answer: E
If the kingdom Plantae is someday expanded to include the charophytes, then the shared derived characteristics of the kingdom will include 1.
rings of cellulose-synthesizing complexes. 2. chlorophylls a and b. 3. alternation of generations. 4. cell walls of cellulose. 5. ability to synthesize sporopollenin. A) 1 and 5 Answer: A
Which of the following were probably factors that permitted early plants to successfully colonize land? 1.
the relative number of potential predators (herbivores) 2. the relative number of competitors 3. the relative availability of symbiotic partners 4. air's relative lack of support, compared to water's support D) 1, 2, and 3 Answer: D
A billionaire buys a sterile volcanic island that recently emerged from the sea. To speed the arrival of conditions necessary for plant growth, the billionaire might be advised to aerially sow what over the island? C) soredia Answer: C
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A botanist discovers a new species of land plant with a dominant sporophyte, chlorophylls a and b, and cell walls made of cellulose. In assigning this plant to a phylum, which of the following, if present, would be least useful? E) spores Answer: E
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A botanist discovers a new species of plant in a tropical rain forest. After observing its anatomy and life cycle, he notes the following characteristics: flagellated sperm, xylem with tracheids, separate gametophyte and sporophyte generations with the sporophyte dominant, and no seeds. This plant is probably most closely related to C) ferns. Answer: C
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A botanist was visiting a tropical region for the purpose of discovering plants with medicinal properties. All of the following might be ways of identifying potentially useful plants except B) observing which plants are the most used food plants. Answer: B
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A fungal spore germinates, giving rise to a mycelium that grows outward into the soil surrounding the site where the spore originally landed. Which of the following accounts for the fungal movement, as described here? E) cytoplasmic streaming in hyphae Answer: E
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A gelatinous seaweed that grows in shallow, cold water and undergoes heteromorphic alternation of generations is most probably what type of alga? C) brown Answer: C
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A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack which of the following? C) holdfasts Answer: C
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A researcher has developed two stains for use with seed plants. One stains sporophyte tissue blue the other stains gametophyte tissue red. If the researcher exposes pollen grains to both stains, and then rinses away the excess stain, what should occur? Answer: C) The pollen grains will have red interiors and blue exteriors.
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A researcher took water in which a Jl population had been thriving, filtered the water to remove all bacterial cells, and then applied the water to the skins of adult amphibians to see if there would subsequently be a reduced infection rate by Bd when frog skins were inoculated with Bd. For which of the following hypotheses is the procedure described a potential test? A) the hypothesis that a toxin secreted by Jl cells kills Bd cells when both are present together on frog skin Answer: A
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A snail-like, coiled, porous test (shell) of calcium carbonate is characteristic of which group? B) foraminiferans Answer: B
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According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria originate? B) from engulfed, originally free-living proteobacteria Answer: B
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After cytokinesis occurs in budding yeasts, the daughter cell has a D) similar nucleus and less cytoplasm than the mother cell. Answer: D
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All fungi share which of the following characteristics? B) heterotrophic Answer: B
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All of the following are common to both charophytes and land plants except B) lignin. Answer: B
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All of the following cellular structures are functionally important in cells of the gametophytes of both angiosperms and gymnosperms except D) chloroplasts. Answer: D
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All protists are B) eukaryotic. Answer: B
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Among sac fungi, which of these correctly distinguishes ascospores from conidia? C) Ascospores have undergone genetic recombination during their production, whereas conidia have not. Answer: C
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Among the organisms listed here, which are thought to be the closest relatives of fungi? A) animals Answer: A
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An individual mixotroph loses its plastids, yet continues to survive. Which of the following most likely accounts for its continued survival? C) It engulfs organic material by phagocytosis or by absorption. Answer: C
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Angiosperm double fertilization is so-called because it features the formation of D) one embryo involving one sperm cell and an endosperm involving a second sperm cell. Answer: D
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Angiosperms are the most successful terrestrial plants. Which of the following features is unique to them and helps account for their success? C) fruits enclosing seeds Answer: C
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As is true of the gametophytes of all land plants, the gametophytes of true mosses lack stomata. Yet, the feather moss Pleurozium harbors nitrogen-fixing cyanobacteria. Which of the following is a feature of moss gametophytes that is most important for the continued survival of these cyanobacteria in the tissues of the feather moss gametophyte? E) lack of multiple cell layers in "leaves" of "buds" Answer: E
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Asexual reproduction in yeasts occurs by budding. Due to unequal cytokinesis, the "bud" cell receives less cytoplasm than the parent cell. Which of the following should be true of the smaller cell until it reaches the size of the larger cell? A) It should produce fewer fermentation products per unit time. Answer: A
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Biologists have long been aware that the defunct kingdom Protista is polyphyletic. Which of these statements is most consistent with this conclusion? C) The eukaryotic condition has evolved more than once among the protists. Answer: C
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Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because B) all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids. Answer: B
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Both fungus-farming ants and their fungi can synthesize the same structural polysaccharide from the β-glucose. What is this polysaccharide? B) chitin Answer: B
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Carpels and stamens are E) modified sporophylls. Answer: E
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Chemicals, secreted by soil fungi, that inhibit the growth of bacteria are known as E) antibiotics. Answer: E
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Consider two hyphae having equal dimensions: one from a septate species and the other from a coenocytic species. Compared with the septate species, the coenocytic species should have C) less chitin. Answer: C
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Considering that the mature sporophytes of true mosses get their nutrition from the gametophytes on which they grow, and considering these generations as individual plants, what is true of the relationship between true moss sporophytes and gametophytes? D) Sporophytes are parasites of gametophytes. Answer: D
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Cutting down rain forests can lead to B) decreased rainfall. Answer: B
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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? C) How do diatoms with their glasslike valves keep from sinking into poorly lit waters? Answer: C
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During glacial periods in the early evolution of land plants, which of the following would have been a beneficial adaptation regarding the number of stomata per unit surface area, and what accounts for it? B) increased numbers of stomata, to maximize ability to absorb low levels of atmospheric CO2 Answer: B
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Fossil fungi date back to the origin and early evolution of plants. What combination of environmental and morphological change is similar in the evolution of both fungi and plants? D) colonization of land and loss of flagellated cells Answer: D
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Generally, wind pollination is most likely to be found in seed plants that grow B) in dense, single-species stands. Answer: B
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Given its composition and location, the phragmoplast should be directly involved in the D) construction of the cell plate during cytokinesis. Answer: D
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Given the differences between angiosperms and gymnosperms in the development of the integument(s), which of these statements is the most logical consequence? A) The seed coats of angiosperms should be relatively thicker than those of gymnosperms. Answer: A
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Green algae differ from land plants in that many green algae B) are unicellular. Answer: B
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Gymnosperms and angiosperms have the following in common except D) ovaries. Answer: D
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Gymnosperms differ from both extinct and extant (living) ferns because they C) have pollen. Answer: C
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How have fruits contributed to the success of angiosperms? B) by facilitating dispersal of seeds Answer: B
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Hypothetically, one of the major benefits of double fertilization in angiosperms is to D) coordinate developmental timing between the embryo and its food stores. Answer: D
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If Penicillium typically secretes penicillin without disturbing the lichen relationship in which it is engaged, then what must have been true about its partner? A) It should have lacked peptidoglycan in its cell wall. Answer: A
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If all fungi in an environment that perform decomposition were to suddenly die, then which group of organisms should benefit most, due to the fact that their fungal competitors have been removed? C) prokaryotes Answer: C
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If all of their nuclei are equally active transcriptionally, then the cells of both dikaryotic and heterokaryotic fungi, in terms of the gene products they can make, are essentially B) diploid. Answer: B
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If haustoria from the fungal partner were to appear within the photosynthetic partner of a lichen, and if the growth rate of the photosynthetic partner consequently slowed substantially, then this would support the claim that B) lichens are not purely mutualistic relationships. Answer: B
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If humans had been present to build log structures during the Carboniferous period (they weren't), which plant types would have been suitable sources of logs? D) ferns, horsetails, and lycophytes Answer: D
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If infection primarily involves the outermost layers of adult amphibian skin, and if the chytrids use the skin as their sole source of nutrition, then which term best applies to the chytrids? D) aerobic chemoheterotroph Answer: D
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If the Archaeplastidae are eventually designated a kingdom, and if land plants are excluded from this kingdom, then what will be true of this new kingdom? C) It will be paraphyletic. Answer: C
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If we were to apply the most recent technique used to fight potato late blight to the fight against the malarial infection of humans, then we would E) insert genes from a Plasmodium-resistant strain of mosquito into Anopheles mosquitoes. Answer: E
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If you are looking for structures that transfer water and nutrients from a bryophyte gametophyte to a bryophyte sporophyte, then on which part of the sporophyte should you focus your attention? C) foot Answer: C
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If you were faced with the choice of eliminating all mutualistic symbioses involving plants and other organisms (besides humans), with the goal being to preserve the most plant biomass, which of the following would you save from elimination? D) associations between soil fungi and roots or rhizoids Answer: D
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Immediately after karyogamy occurs, which term applies? D) diploid Answer: D
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In animal cells and in the meristem cells of land plants, the nuclear envelope disintegrates during mitosis. This disintegration does not occur in the cells of most protists and fungi. According to our current knowledge of plant evolution, which group of organisms should feature mitosis most similar to that of land plants? C) charophytes Answer: C
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In both lichens and mycorrhizae, what does the fungal partner provide to its photosynthetic partner? D) water and minerals Answer: D
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In life cycles with an alternation of generations, multicellular haploid forms alternate with D) multicellular diploid forms. Answer: D
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In most fungi, karyogamy does not immediately follow plasmogamy, which consequently D) results in heterokaryotic or dikaryotic cells. Answer: D
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In plants, which of the following are produced by meiosis? D) haploid spores Answer: D
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In seed plants, which of the following is part of a pollen grain and has a function most like that of the seed coat? C) sporopollenin Answer: C
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In septate fungi, what structures allow cytoplasmic streaming to distribute needed nutrients, synthesized compounds, and organelles throughout the hyphae? B) pores in cross-walls Answer: B
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In terms of alternation of generations, the internal parts of the pollen grains of seed-producing plants are most similar to a E) fern gametophyte bearing only antheridia. Answer: E
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In what structures do both Penicillium and Aspergillus produce asexual spores? E) conidiophores Answer: E
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In which of the following taxa does the mature sporophyte depend completely on the gametophyte for nutrition? B) Bryophyta Answer: B
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Increasing the number of stomata per unit surface area of a leaf when atmospheric CO2 levels decline is most analogous to a human B) putting more red blood corpuscles (RBCs) into circulation when atmospheric O2 levels decline. Answer: B
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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? B) The coral animals' endosymbiotic dinoflagellates may get "shaded out" by the diatoms. Answer: B
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Many infected animals are induced by the parasitic microsporidians to develop huge cells, known as xenomas, which are full of spores. Given their large size, what should be true of the xenomas? A) The parasite must endow the xenoma with some way to overcome its unfavorable surface area-to-volume ratio. Answer: A
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Many mammals have skins and mucous membranes that are sensitive to phenolic secretions of plants like poison oak (Rhus). These secondary compounds are primarily adaptations that E) inhibit herbivory. Answer: E
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Microphylls are found in which plant group? C) lycophytes Answer: C
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Mycorrhizae are to the roots of vascular plants as endophytes are to vascular plants' A) leaf mesophyll. Answer: A
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On a field trip, a student in a marine biology class collects an organism that has differentiated organs, cell walls of cellulose, and chloroplasts with chlorophyll a. Based on this description, the organism could be a brown alga, a red alga, a green alga, a charophyte recently washed into the ocean from a freshwater or brackish water source, or a land plant washed into the ocean. The presence of which of the following features would definitively identify this organism as a land plant? E) embryos Answer: E
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Orchid seeds are tiny, with virtually no endosperm and with miniscule cotyledons. If such seeds are deposited in a dark, moist environment, then which of the following represents the most likely means by which fungi might assist in seed germination, given what the seeds lack? C) by providing the embryos with some of the organic nutrients they have absorbed Answer: C
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Plasmogamy can directly result in which of the following? 1. cells with a single haploid nucleus 2. heterokaryotic cells 3. dikaryotic cells 4. cells with two diploid nuclei C) 2 or 3 Answer: C
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Sexual reproduction has never been observed among the fungi that produce the blue-green marbling of blue cheeses. What is true of these fungi and others that do not have a sexual stage? C) Their spores are probably produced by mitosis. Answer: C
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Sexual reproduction has not been observed in Bd. If its morphology and genetics did not identify it as a chytridiomycete, then to which fungal group would Bd be assigned? E) deuteromycetes Answer: E
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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, what would be true of such a taxon? A) It would be polyphyletic. Answer: A
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Some fungi can exist either as unicellular yeasts or as filamentous hyphae. Which of these forms would be most favorable in an environment where nutrients are limited? D) a longer filamentous hypha Answer: D
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Some green algae exhibit alternation of generations. All land plants exhibit alternation of generations. No charophytes exhibit alternation of generations. Keeping in mind the recent evidence from molecular systematics, the correct interpretation of these observations is that B) plants evolved alternation of generations independently of green algae. Answer: B
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Sporophylls can be found in which of the following? D) pterophytes Answer: D
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Structurally, phragmoplasts should be most similar to E) spindle fibers. Answer: E
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Suppose an efficient conducting system evolved in a moss that could transport water and other materials as high as a tall tree. Which of the following statements about "trees" of such a species would not be true? C) Females could produce only one archegonium. Answer: C
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Surface area represents the area available for exchange with the environment, whereas volume represents the cytoplasm which requires nutrients and from which waste products (usually toxic) must be removed. Which of the following should provide the most favorable conditions for effective exchange? D) a longer filamentous hypha Answer: D
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The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to E) an extensive surface area well suited for invasive growth and absorptive nutrition. Answer: E
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The best evidence for not classifying the slime molds as fungi comes from slime molds' A) DNA sequences. Answer: A
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The chloroplasts of all of the following are thought to be derived from ancestral red algae, except those of D) green algae. Answer: D
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The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence? A) cyanobacteria → green algae → land plants Answer: A
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The fact that infection by Bd causes lethargy in many infected amphibians can have what effect on efforts to accurately census the numbers of dead or dying amphibians at a particular time, in a particular habitat? E) Two of the above statements are plausible. Answer: E
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The following are all adaptations to life on land except A) rings of cellulose-synthesizing complexes. Answer: A
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The fruit of the mistletoe, a parasitic angiosperm, is a one-seeded berry. In members of the genus Viscum, the outside of the seed is viscous (sticky), which permits the seed to adhere to surfaces, such as the branches of host plants or the beaks of birds. What should be expected of the fruit if the viscosity of Viscum seeds is primarily an adaptation for dispersal rather than an adaptation for infecting host plant tissues? C) It should be nutritious. Answer: C
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The functional role of sporopollenin is primarily to B) reduce dehydration. Answer: B
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The functional significance of porous septa in certain fungal hyphae is most similar to that represented by which pair of structures in animal cells and plant cells, respectively? B) gap junctionsplasmodesmata Answer: B
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The generative cell of male angiosperm gametophytes is haploid. This cell divides to produce two haploid sperm cells. What type of cell division does the generative cell undergo to produce these sperm cells? B) mitosis Answer: B
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The hydrolytic digestion of which of the following should produce monomers that are aminated (i.e., have an amine group attached) molecules of β-glucose? E) Two of these responses are correct. Answer: E
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The leaflike appendages of moss gametophytes may be one to two cell layers thick. Consequently, which of the following is least likely to be found associated with such appendages? C) stomata Answer: C
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The multicellular condition of animals and fungi seems to have arisen B) by convergent evolution. Answer: B
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The photosynthetic symbiont of a lichen is often B) a green alga. Answer: B
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The seed coat's most important function is to provide E) desiccation resistance. Answer: E
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The seeds of orchids are among the smallest known, with virtually no endosperm and with miniscule seed leaves. Consequently, what should one expect to be true of such seeds? C) They germinate very soon after being released from the ovary. Answer: C
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The structural integrity of bacteria is to peptidoglycan as the structural integrity of plant spores is to D) sporopollenin. Answer: D
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The vegetative (nutritionally active) bodies of most fungi are D) Three of these responses are correct. Answer: D
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What accounts most directly for the extremely fast growth of a fungal mycelium? A) rapid distribution of synthesized proteins by cytoplasmic streaming Answer: A
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What are the sporangia of the bread mold Rhizopus? A) asexual structures that produce haploid spores Answer: A
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What do fungi and arthropods have in common? D) The protective coats of both groups are made of chitin. Answer: D
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What is the greatest threat to plant diversity? E) human population growth Answer: E
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What is true of charophytes? C) They are the closest living algal relatives of land plants. Answer: C
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What is true of stamens, sepals, petals, carpels, and pinecone scales? C) They are modified leaves. Answer: C
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What makes it risky to rely on the presence of chitin in adult amphibian skin as the sole positive test for the presence of chytrids? E) Two of the responses above are correct. Answer: E
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When a mycelium infiltrates an unexploited source of dead organic matter, what are most likely to appear within the food source soon thereafter? C) fungal enzymes Answer: C
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When pathogenic fungi are found growing on the roots of grape vines, grape farmers sometimes respond by covering the ground around their vines with plastic sheeting and pumping a gaseous fungicide into the soil. The most important concern of grape farmers who engage in this practice should be that the C) fungicide might also kill mycorrhizae. Answer: C
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Where in an angiosperm would you find a megasporangium? D) within an ovule contained within an ovary of a flower Answer: D
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Which description does not apply equally well to both sexual and asexual spores? C) are produced by meiosis Answer: C
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Which event during the evolution of land plants probably made the synthesis of secondary compounds most beneficial? D) the rise of herbivory Answer: D
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Which feature seen in chytrids supports the hypothesis that they diverged earliest in fungal evolution? C) flagellated spores Answer: C
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Which group is incorrectly paired with its description? C) red algaeacquired plastids by secondary endosymbiosis Answer: C
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Which group is noted for the independence of gametophyte and sporophyte generations from each other? A) ferns Answer: A
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Which of the following are actual mutualistic partnerships that involve a protist and a host organism? E) all except that involving humans Answer: E
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Which of the following are land plants that use the same means of getting sperm to egg that algae use? D) Two of the responses above are correct. Answer: D
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Which of the following are protists, the organisms thought to share the closest ancestor with the chytrids? A) nucleariids Answer: A
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Which of the following are structures of angiosperm gametophytes? B) pollen tubes Answer: B
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Which of the following best describes the physical relationship of the partners involved in lichens? C) Photosynthetic cells are surrounded by fungal hyphae. Answer: C
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Which of the following cells or structures are associated with asexual reproduction in fungi? D) conidiophores Answer: D
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Which of the following characteristics helped seedless plants better adapt to life on land? D) stomata on leaves Answer: D
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Which of the following characteristics is shared by both chytrids and other kinds of fungi? E) nucleotide sequences of several genes Answer: E
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Which of the following characteristics of plants is absent in their closest relatives, the charophyte algae? E) alternation of multicellular generations Answer: E
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Which of the following conditions is caused by a fungus that is accidentally consumed along with rye flour? A) ergotism Answer: A
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Which of the following flower parts develops into a seed? A) ovule Answer: A
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Which of the following flower parts develops into the pulp of a fleshy fruit? D) ovary Answer: D
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Which of the following has the least affiliation with all of the others? C) lichens Answer: C
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Which of the following is a characteristic of all angiosperms? B) double internal fertilization Answer: B
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Which of the following is a characteristic of hyphate fungi (fungi featuring hyphae)? D) They are adapted for rapid directional growth to new food sources. Answer: D
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Which of the following is a characteristic of the water molds (oomycetes)? A) the presence of filamentous feeding structures Answer: A
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Which of the following is a land plant that has flagellated sperm and a sporophyte-dominated life cycle? A) fern Answer: A
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Which of the following is a true statement about angiosperm carpels? D) Carpels surround and nourish the female gametophyte. Answer: D
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Which of the following is a true statement about plant reproduction? B) Both male and female bryophytes produce gametangia. Answer: B
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Which of the following is correctly described as a primary producer? D) diatom Answer: D
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Which of the following is most important in making the typical seed more resistant to adverse conditions than the typical spore? C) integument(s) Answer: C
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Which of the following is not a characteristic that distinguishes gymnosperms and angiosperms from other plants? A) alternation of generations Answer: A
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Which of the following is not evidence that charophytes are the closest algal relatives of plants? B) the presence of chloroplasts Answer: B
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Which of the following is true concerning flowering plants? A) The flower includes sporophyte tissue. Answer: A
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Which of the following is true of seedless vascular plants? B) Whole forests were dominated by large, seedless vascular plants during the Carboniferous period. Answer: B
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Which of the following is true of the life cycle of mosses? C) Antheridia and archegonia are produced by gametophytes. Answer: C
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Which of the following pairs of protists and their characteristics is mismatched? D) ciliates-red tide organisms Answer: D
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Which of the following sex and generation combinations most directly produces the fruit? D) female sporophyte Answer: D
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Which of the following sex and generation combinations most directly produces the integument of a pine seed? D) female sporophyte Answer: D
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Which of the following sex and generation combinations most directly produces the megasporangium of pine ovules? D) female sporophyte Answer: D
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Which of the following sex and generation combinations most directly produces the pollen tube? A) male gametophyte Answer: A
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Which of the following should have had gene sequences most similar to the charophyte that was the common ancestor of the land plants? B) early bryophytes Answer: B
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Which of the following statements about dinoflagellates is true? A) They possess two flagella. Answer: A
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Which of the following statements concerning protists is true? A) All protists have mitochondria, though in some species they are much reduced and known by different names. Answer: A
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Which of the following statements correctly describes a portion of the pine life cycle? A) Female gametophytes use mitosis to produce eggs. Answer: A
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Which of the following statements is true of archegonia? B) They may temporarily contain sporophyte embryos. Answer: B
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Which of the following statements is true of deuteromycetes? C) They are the group of fungi that have, at present, no known sexual stage. Answer: C
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Which of the following statements is true of monocots? C) They, along with the eudicots, magnoliids, and basal angiosperms, are currently placed in the phylum Anthophyta. Answer: C
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Which of the following statements is true of the pine life cycle? D) Conifer pollen grains contain male gametophytes. Answer: D
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Which of the following terms refers to symbiotic relationships that involve fungi living between the cells in plant leaves? C) endophytes Answer: C
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Which of the following was derived from an ancestral cyanobacterium? A) chloroplast Answer: A
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Which of the following was not a challenge for survival of the first land plants? D) animal predation Answer: D
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Which of these paired fungal structures are structurally and functionally most alike? D) haustoria and arbuscules Answer: D
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Which pair of alternatives is highlighted by the life cycle of the cellular slime molds, such as Dictyostelium? B) unicellular or multicellular Answer: B
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Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without the net loss of any genetic information? B) horizontal gene transfer Answer: B
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Which process occurs in fungi and has the opposite effect on a cell's chromosome number than does meiosis I? E) karyogamy Answer: E
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Which process results in genetic recombination, but is separate from the process by which the population size of Paramecium increases? D) conjugation Answer: D
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Which protists are in the same eukaryotic supergroup as land plants? E) both green algae and red algae Answer: E
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Which structure is common to both gymnosperms and angiosperms? C) ovule Answer: C
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Which structure(s) must pass through the micropyle for successful fertilization to occur in angiosperms? D) Two of the responses above are correct. Answer: D
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Which taxon is essentially equivalent to the "embryophytes"? B) Plantae Answer: B
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Why is the filamentous morphology of the water molds considered a case of convergent evolution? C) In both cases, filamentous shape is an adaptation for the absorptive nutritional mode of a decomposer. Answer: C
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With respect to angiosperms, which of the following is incorrectly paired with its chromosome count? B) megaspore-2n Answer: B
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You are designing an artificial drug-delivery "cell" that can penetrate animal cells. Which of these protist structures should provide the most likely avenue for research along these lines? B) apical complex Answer: B
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You are given an organism to identify. It has a fruiting body that contains many structures with eight haploid spores lined up in a row. What kind of a fungus is this? B) ascomycete Answer: B
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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 three nuclei, one large and two small. This organism is most likely to be a member of which group? C) ciliates Answer: C
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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. Answer: A
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You are hiking in a forest and come upon a mysterious plant, which you determine is either a lycophyte sporophyte or a pterophyte sporophyte. Which of the following would be most helpful in determining the correct classification of the plant? B) whether it has microphylls or megaphylls Answer: B
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You are hiking in a forest and happen upon a plant featuring a central stemlike structure from which sprout many, tiny, leaflike structures. Which of the following would be the most certain means of distinguishing whether it was a true moss or a club moss? E) the appearance of its spore-producing structures Answer: E
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The microsporidian, Brachiola gambiae, parasitizes the mosquito, Anopheles gambiae. Adult female mosquitoes must take blood meals in order 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 true?
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 other food webs. 5. Brachiola must be harmful to male mosquitoes, but not to female mosquitoes. C) three statements Answer: C
A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. This alga probably belongs to which group? A) red algae Answer: A
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A fruit is most commonly A) a mature ovary. Answer: A
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At some time during their existence, bryophytes may feature D) sporangia. Answer: D
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Both fungus-derived antibiotics and hallucinogens used by humans probably evolved in fungi as a means to A) reduce competition for nutrients. Answer: A
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If a fern gametophyte is a hermaphrodite (that is, has both male and female gametangia on the same plant), then it A) belongs to a species that is homosporous. Answer: A
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In addition to seeds, which of the following characteristics are unique to the seed-producing plants? C) pollen Answer: C
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Lichens are symbiotic associations of fungi and E) Two of these responses are correct. Answer: E
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Mitotic activity by the apical meristem of a root makes which of the following more possible? A) increase of the aboveground stem. Answer: A
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Over human history, which process has been most important in improving the features of plants that have long been used by humans as staple foods? B) artificial selection Answer: B
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Plastids that are surrounded by more than two membranes are evidence of D) secondary endosymbiosis. Answer: D
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Reinforced, threadlike pseudopods that can perform phagocytosis are generally characteristic of which group? A) radiolarians and forams Answer: A
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Reptilian embryos are protected from desiccation by a leathery shell. Similarly, which pair of structures protects seed plants' embryos and male gametophytes, respectively, from desiccation? E) integumentssporopollenin Answer: E
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Which of the following can be found in gymnosperms? D) pollen Answer: D
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Which of the following is characteristic of ciliates? E) They are often multinucleate. Answer: E
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Arrange the following from largest to smallest, assuming that they all come from the same fungus.
1. basidiocarp 2. basidium 3. basidiospore 4. mycelium 5. gill E) 4 → 1 → 5 → 2 → 3 Answer: E
"The Brazil nut tree, Bertholletia excels (n = 17)..." Orchid bees are to Brazil nut trees as ________ are to pine trees.
Answer: A) breezes
"The Brazil nut tree, Bertholletia excels (n = 17)..." The taller a Brazil nut tree is,
Answer: C) 1 and 3
"The Brazil nut tree, Bertholletia excels (n = 17)..." Native peoples traditionally use Brazil nuts to treat stomach ache, inflammation, hypersensitivity, and hepatitis. Consequently, a scientist should be interested in promoting
Answer: D) the evaluation of Brazil nut chemicals for use as potential drugs.
"The Brazil nut tree, Bertholletia excels (n = 17)..." If a female orchid bee has just left a Brazil nut tree with nectar in her stomach, and if she visits another flower on a different Brazil nut tree, what is the sequence in which the following events should occur?
double fertilization pollen tube emerges from pollen grain pollen tube enters micropyle pollination Answer: A) 4, 2, 3, 1
Beginning with the germination of a moss spore, what is the sequence of structures that develop after germination? 1.
embryo 2. gametes 3. sporophyte 4. protonema 5. gametophore C) 4 → 5 → 2 → 1 → 3 Answer: C
Arrange the following terms from most inclusive to least inclusive. 1.
embryophytes 2. green plants 3. seedless vascular plants 4. ferns 5. tracheophytes B) 2, 1, 5, 3, 4 Answer: B
You are given the task of designing an aerobic, mixotrophic protist that can perform photosynthesis in fairly deep water (for example, 250 m deep), and can also crawl about and engulf small particles. With which two of the following structures would you provide your protist? 1.
hydrogenosome 2. apicoplast 3. pseudopods 4. chloroplast from red alga 5. chloroplast from green alga D) 3 and 4 Answer: D
Assuming that they all belong to the same plant, arrange the following structures from largest to smallest (or from most inclusive to least inclusive). 1.
spores 2. sporophylls 3. sporophytes 4. sporangia E) 3, 2, 4, 1 Answer: E
What is thought to be the correct sequence of the following events during the Carboniferous period? 1.
vascular plants become more prevalent 2. megaphylls with large surface areas become more prevalent 3. atmospheric CO2 levels decline by a factor of five 4. global cooling occurs, leading to widespread glaciations A) 1, 2 ,3, 4 Answer: A
Sexual reproduction has not been observed in Bd. A Bd sporangium initially contains a single, haploid cell. Which of the following processes must be involved in generating the multiple zoospores eventually produced by each sporangium?
1. S phase 2. cytokinesis 3. mitosis 4. meiosis D) 1, 2, and 3 Answer: D
What adaptations should one expect of the seed coats of angiosperm species whose seeds are dispersed by frugivorous (fruit-eating) animals, as opposed to angiosperm species whose seeds are dispersed by other means?
1. The exterior of the seed coat should have barbs or hooks. 2. The seed coat should contain secondary compounds that irritate the lining of the animal's mouth. 3. The seed coat should be able to withstand low pH's. 4. The seed coat, upon its complete digestion, should provide vitamins or nutrients to animals. 5. The seed coat should be resistant to the animals' digestive enzymes. D) 3 and 5 Answer: D
Among plants known as legumes (beans, peas, alfalfa, clover, etc.) the seeds are contained in a fruit that is itself called a legume, better known as a pod. Upon opening such pods, it is commonly observed that some ovules have become mature seeds, whereas other ovules have not. Thus, which of the following statements is (are) true?
1. The flowers that gave rise to such pods were not pollinated. 2. Pollen tubes did not enter all of the ovules in such pods. 3. There was apparently not enough endosperm to distribute to all of the ovules in such pods. 4. The ovules that failed to develop into seeds were derived from sterile floral parts. 5. Fruit can develop, even if all ovules within have not been fertilized. A) 1 only B) 1 and 5 C) 2 and 4 D) 2 and 5 E) 3 and 5 Answer: D
The cutting and burning of tropical rain forests leads to which of the following?
1. addition of CO2 to the atmosphere 2. decreased removal of CO2 from the atmosphere 3. greenhouse effect 4. global warming 5. decreasing sea level D) 1, 2, 3, and 4 Answer: D
Arrange the following from largest to smallest:
1. ascospore 2. ascocarp 3. ascomycete 4. ascus B) 3 → 2 → 4 → 1 Answer: B
Suppose that the cells of seed plants, like the skin cells of humans, produce a pigment upon increased exposure to UV radiation. Rank the following cells, from greatest to least, in terms of the likelihood of producing this pigment.
1. cells of sporangium 2. cells in the interior of a subterranean root 3. epidermal cells of sporophyte megaphylls 4. cells of a gametophyte C) 3, 1, 4, 2 Answer: C
Which of the following microsporidian features are shared with many other fungi?
1. chitinous cell wall 2. two haploid nuclei per cell 3. polar filament 4. chemoheterotrophy D) 1, 2, and 4 Answer: D
If Bd cannot grow properly at temperatures above 28°C (82°F), then, assuming the amphibians can survive, in which time or place should the chytrid infection proceed most rapidly?
1. cooler months 2. warmer months 3. lower altitudes 4. higher altitudes B) 1 or 4 Answer: B
In a typical angiosperm, what is the sequence of structures encountered by the tip of a growing pollen tube on its way to the egg?
1. micropyle 2. style 3. ovary 4. stigma A) 4 → 2 → 3 → 1 Answer: A
Arrange the following structures from largest to smallest, assuming that they belong to two generations of the same angiosperm.
1. ovary 2. ovule 3. egg 4. carpel 5. embryo sac E) 4, 1, 2, 5, 3 Answer: E
Which trait(s) is (are) shared by many modern gymnosperms and angiosperms?
1. pollen transported by wind 2. lignified xylem 3. microscopic gametophytes 4. sterile sporophylls, modified to attract pollinators 5. endosperm C) 1, 2, and 3 Answer: C
Arrange the following structures, which can be found on male pine trees, from the largest structure to the smallest structure (or from most inclusive to least inclusive).
1. sporophyte 2. microspores 3. microsporangia 4. pollen cone 5. pollen nuclei A) 1, 4, 3, 2, 5 Answer: A
Arrange the following in the correct sequence, from earliest to most recent, in which these plant traits originated.
1. sporophyte dominance, gametophyte independence 2. sporophyte dominance, gametophyte dependence 3. gametophyte dominance, sporophyte dependence E) 3 → 1 → 2 Answer: E
Within a gymnosperm megasporangium, what is the correct sequence in which the following should appear during development, assuming that fertilization occurs?
1. sporophyte embryo 2. female gametophyte 3. egg cell 4. megaspore B) 4 → 2 → 3 → 1 Answer: B
The Brazil nut tree, Bertholletia excels (n = 17), is native to tropical rain forests of South America. It is a hardwood tree that can grow to over 50 meters, is a source of high-quality lumber, and is a favorite nesting site for harpy eagles. As the rainy season ends, tough-walled fruits, each containing 825 seeds (Brazil nuts), fall to the forest floor. About $50 million worth of nuts are harvested each year. Scientists have discovered that the pale yellow, self-incompatible flowers of Brazil nut trees admit only female orchid bees as pollinators.
Animals that consume Brazil nuts are deriving nutrition mostly from tissue whose nuclei have how many chromosomes? Answer: C) 51 The agouti (Dasyprocta spp.), a cat-sized rodent, is the only animal with teeth strong enough to crack the hard wall of Brazil nut fruits. It typically eats some of the seeds, buries others, and leaves still others behind inside the fruit, which moisture can now enter. The uneaten seeds may subsequently germinate. Consequently, which terms describe the relationship between the Brazil nut tree and the agouti? parasitic commensalistic symbiotic endosymbiotic mutualistic Answer: D) 3 and 5
"The Brazil nut tree, Bertholletia excels (n = 17)..." People who attempted to plant Brazil nuts in hopes of establishing plantations of Brazil nut trees played roles most similar to those of
Answer: A) agoutis.
"The Brazil nut tree, Bertholletia excels (n = 17)..." The harpy eagle, Harpia harpyja, is the largest, most powerful raptor in the Americas. It nests only in trees taller than 25 meters. It is a "sloth specialist," but will also take agouti. Thus, if these eagles capture too many agoutis from a particular locale, they might contribute to their own demise by
Answer: B) increasing habitat loss.
"The Brazil nut tree, Bertholletia excels (n = 17)..." The same bees that pollinate the flowers of the Brazil nut trees pollinate orchids, which are epiphytes (in other words, plants that grow on other plants); however, orchids cannot grow on Brazil nut trees. These observations explain
Answer: B) why Brazil nut trees do not set fruit in plantations.
When adult amphibian skin harbors populations of the bacterium, Janthinobacterium lividum (Jl), chytrid infection seems to be inhibited. Which of the following represents the best experimental design for conclusively determining whether this inhibition is real?
Answer: C) Take infected amphibians and assign them to two populations. Leave one population alone inoculate the other with Jl. Measure the rate at which infection proceeds in both populations.
"The Brazil nut tree, Bertholletia excels (n = 17)..." The agouti is most directly involved with the Brazil nut tree's dispersal of
Answer: C) sporophyte embryos.
"The Brazil nut tree, Bertholletia excels (n = 17)..." Brazil nut trees begin producing fruit at the age of 10 years, reach final height at about 120 years, and can live for over 500 years. A landowner can earn more by felling a Brazil nut tree and selling it for lumber than from several seasons' worth of Brazil nut harvests from the same tree. Thus, it makes greater financial sense in the long run to harvest
Answer: C) the nuts for many seasons.
"The Brazil nut tree, Bertholletia excels (n = 17)..." To help ensure a prosperous future for the largest number of people, developed countries should
Answer: D) reuse, recycle, and reduce at home, while encouraging the same abroad.
"The Brazil nut tree, Bertholletia excels (n = 17)..." If a female orchid bee has just left a Brazil nut tree with nectar in her stomach, and if she visits only other flowers on the same tree, the result should be
Answer: E) Two of the responses above are correct.
"The Brazil nut tree, Bertholletia excels (n = 17)..." Entrepreneurs attempted, but failed, to harvest nuts from plantations grown in Southeast Asia. Attempts to grow Brazil nut trees in South American plantations also failed. In both cases, the trees grew vigorously, produced healthy flowers in profusion, but set no fruit. Consequently, what is the likely source of the problem?
Answer: E) pollination failure
"The Brazil nut tree, Bertholletia excels (n = 17)..." In the long run, harvesting Brazil nut trees for their lumber is most likely to benefit
Answer: E) sloths.
For several decades now, amphibian species worldwide have been in decline. A significant proportion of the decline seems to be due to the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Chytrid sporangia reside within the epidermal cells of infected animals, animals that consequently show areas of sloughed skin. They can also be lethargic, which is expressed through failure to hide and failure to flee. The infection cycle typically takes four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100% other species seem able to survive the infection.
Apart from direct amphibian-to-amphibian contact, what is the most likely means by which the zoospores spread from one free-living amphibian to another? B) by flagella Answer: B The chytrid sporangia reside within the amphibian epidermal cells. Consequently, which term(s) apply to Bd? 1. ectosymbionts 2. parasites 3. commensals 4. pathogens 5. endosymbionts E) 2, 4, and 5 Answer: E
Two small, poorly drained lakes lie close to each other in a northern forest. The basins of both lakes are composed of the same geologic substratum. One lake is surrounded by a dense Sphagnum mat,the other is not. Compared to the pond with Sphagnum, the pond lacking the moss mat should have
D) less-acidic water. Answer: D
Recent genetic studies of the structure of microsporidian genomes, as well as the sequences of their tubulin genes and the gene for RNA polymerase II, indicate that microsporidians are closely related to the fungi. Microsporidians lack flagella, centrioles, peroxisomes, and mitochondria (although they do have degenerate mitochondria, called mitosomes). They have the smallest genome of any eukaryote, and it is a genome that changes quickly. The genome is contained within two haploid nuclei. All microsporidians are obligate intracellular parasites. They use a unique organelle called a polar filament to gain access to the cells of their hosts. One species causes chronic diarrhea in AIDS patients. Another parasitizes Anopheles gambiae, the mosquito that transmits a fatal form of malaria to humans.
Given the eukaryotic structures they lack, it should be expected that microsporidians also lack A) the "9 + 2 pattern" of microtubules. Answer: A The lifestyle of microsporidians is most similar to that of B) viruses. Answer: B
In onions (Allium), cells of the sporophyte have 16 chromosomes within each nucleus. Match the number of chromosomes present in each of the following onion tissues.
How many chromosomes should be in a tube cell nucleus? A) 4 B) 8 C) 16 D) 24 E) 32 Answer: B How many chromosomes should be in an endosperm nucleus? A) 4 B) 8 C) 16 D) 24 E) 32 Answer: D How many chromosomes should be in a generative cell nucleus? A) 4 B) 8 C) 16 D) 24 E) 32 Answer: B How many chromosomes should be in an embryo sac nucleus? A) 4 B) 8 C) 16 D) 24 E) 32 Answer: B How many chromosomes should be in an embryo nucleus? A) 4 B) 8 C) 16 D) 24 E) 32 Answer: C How many chromosomes should be in a megasporangium nucleus? A) 4 B) 8 C) 16 D) 24 E) 32 Answer: C
Diploid nuclei of the ascomycete, Neurospora crassa, contain 14 chromosomes. A single diploid cell in an ascus will undergo one round of meiosis, followed in each of the daughter cells by one round of mitosis, producing a total of eight ascospores.
If a single, diploid G2 nucleus in an ascus contains 400 nanograms (ng) of DNA, then a single ascospore nucleus of this species should contain how much DNA (ng), carried on how many chromosomes? A) 100, carried on 7 chromosomes B) 100, carried on 14 chromosomes C) 200, carried on 7 chromosomes D) 200, carried on 14 chromosomes E) 400, carried on 14 chromosomes Answer: A What is the ploidy of a single mature ascospore? A) monoploid B) diploid C) triploid D) tetraploid E) polyploid Answer: A Each of the eight ascospores present at the end of mitosis has the same chromosome number and DNA content (ng) as each of the four cells at the end of meiosis. What must have occurred in each spore between the round of meiosis and the round of mitosis? A) double fertilization B) crossing over C) nondisjunction D) autopolyploidy E) S phase Answer: E
Harold and Kumar are pre-med and pre-pharmacy students, respectively. They complain to their biology professor that they should not have to study about plants because plants have little relevance to their chosen professions.
It would be best for these students, and for society in the long run, if their biology professor responds by Answer: C) offering extra credit for a research paper on plants that harm humans, as well as plants that heal humans. From reading their biology textbook, what would Harold and Kumar discover? Answer: A) About one-quarter of all prescription drugs come from seed plants. Kumar, especially, might be well advised to learn more about Answer: B) secondary metabolites. Which adaptation(s) of land plants is (are) likely to provide Harold with future patients? Answer: E) Two of the responses above are potentially medically significant.
Of the following list, flagellated (swimming) sperm are generally present in which groups? 1.
Lycophyta 2. Bryophyta 3. Angiosperms 4. Chlorophyta 5. Pterophyta B) 1, 2, 4, and 5 Answer: B
Which two genera have members that can evade the human immune system by frequently changing their surface proteins? 1.
Plasmodium 2. Trichomonas 3. Paramecium 4. Trypanosoma 5. Entamoeba B) 1 and 4 Answer: B
Rose-picker's disease is caused by the yeast, Sporothrix schenkii. The yeast grows on the exteriors of rose-bush thorns. If a human gets pricked by such a thorn, the yeasts can be introduced under the skin. The yeasts then assume a hyphal morphology and grow along the interiors of lymphatic vessels until they reach a lymph node. This often results in the accumulation of pus in the lymph node, which subsequently ulcerates through the skin surface and then drains.
The answer to which of these questions would be of most assistance to one who is attempting to assign the genus Sporothrix to the correct fungal phylum? B) Does S. schenkii rely on animal infection to complete some part of its life cycle, or is the infection merely opportunistic? Answer: B Say S. schenkii had initially been classified as a deuteromycete. Asci were later discovered in the pus that oozed from an ulcerated lymph node, and the spores therein germinated, giving rise to S. schenkii yeasts. Which two of these are conclusions that make sense on the basis of this information?1. S. schenkii produces asexual spores within lymph nodes. 2. S. schenkii should be reclassified. 3. S. schenkii continues to have no known sexual stage. 4. The hyphae growing in lymphatic vessels probably belonged to a different fungal species. 5. S. schenkii yeasts belonging to two different mating strains were introduced by the same thorn prick. D) 2 and 5 Answer: D Humans have immune systems in which lymph nodes are important, because many phagocytes and lymphocytes reside there. Given that a successful infection by S. schenkii damages lymph nodes themselves, which of the following is most probable? B) Their conversion from yeast to hyphal morphology allows such fast growth that the body's defenses are at least temporarily overwhelmed. Answer: B
Paulinella chromatophora is one of the few cercozoans that is autotrophic, carrying out aerobic photosynthesis with its two elongated "cyanelles." The cyanelles 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. What type of evidence permits biologists to make this claim about relatedness? D) genetic Answer: D 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? C) a vacuole with food inside Answer: C 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 Answer: A Which of the following represents the true significance of the finding that the cyanelles of P. chromatophora stem from a different type of cyanobacterium than gave rise to chloroplasts? A) This finding indicates that there is a second evolutionary lineage of photosynthetic eukaryotes. Answer: A 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 cyanelle 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 conclusion that can be drawn from this comparison? B) P. chromatophora's cyanelle is the result of an evolutionarily recent endosymbiosis. Answer: B If true, which of the following would be most important in determining whether P. chromatophora's cyanelle is still an endosymbiont, or is an organelle, as the term cyanelle implies? E) If there has been movement of genes from the cyanelle genome to the nuclear genome, such that these genes are no longer present in the cyanelle genome. Answer: E If true, which of the following is the best evidence that the cyanelles are providing nutrition (in other words, calories) to the surrounding cercozoan? D) If radiolabeled 14CO2 enters the cyanelle and if, subsequently, radiolabeled glucose is present in cercozoan cytosol. Answer: D A crucial photosynthetic gene of the cyanobacterium that gave rise to the cyanelle is called psaE. This gene is present in the nuclear genome of the cercozoan, but is not in the genome of the cyanelle. This is evidence of B) horizontal gene transfer from bacterium to eukaryotes. Answer: B What must occur for asexual reproduction to be successful in P. chromatophora? 1. mitosis 2. S phase 3. meiosis 4. equal distribution of cyanelles during cytokinesis D) 1, 2, and 4 Answer: D 64) Including the membrane of the surrounding vesicle, how many phospholipid (NOT lipopolysaccharide) bilayers should be found around each cyanelle, and which one of these bilayers should have photosystems embedded in it? A) two Answer: A
Giardia lamblia 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 trophozoites of Giardia were first observed in 1681 in the diarrhea stools of the first known person to view protists with a microscope, a person named D) van Leeuwenhoek. Answer: D Given that Flagyl produces only minor side effects (if any) in humans, and given the set of parasites that it kills, Flagyl's mode of action probably involves C) anaerobic metabolic pathways. Answer: C Giardia's mitosome can be said to be "doubly degenerate," because it is a degenerate form of ________, an organelle that is itself a degenerate form of ________. Answer: C) mitochondrion proteobacterium 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? D) 2, 4, and 5 Answer: D 47) Given the putative ancestry of Giardia's mitosome, what should we predict is true of the mitosome? B) It has a double membrane. Answer: B 48) 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) 1 only Answer: A Unlike most excavates, Giardia trophozoites have no oral groove and are unable to form food vacuoles. Thus, we should expect its nutrition (mostly glucose) to come from E) plasma membrane proteins that are transporters or pumps. Answer: E Diplomonads, such as Giardia, contain two haploid nuclei per trophozoite. Thus, during the G1 phase of the cell cycle, there should be a total of how many unreplicated chromosomes per trophozoite, and during the G2 phase, how many replicated chromosomes per trophozoite? Answer: C) 10 10 During passage through the large intestine, a trophozoite will often secrete a case around itself, forming a cyst. Cysts contain four haploid nuclei. When cysts "hatch" within a new host, two trophozoites are released. Thus, which of the following must happen within the cyst, prior to hatching? E) 2, 3, and 4 Answer: E The cysts of Giardia are most analogous to the. C) endospores of bacteria. Answer: C 53) 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? Answer: C) nucleus The primary treatment for giardiasis (infection with Giardia), as well as for trichomoniasis (infection with Trichomonas vaginalis) and for amoebic dysentery (infection with Entamoeba histolytica), is a drug marketed as Flagyl (generic name is metronidazole). The drug also kills anaerobic gut bacteria. Consequently, which of these are cues that Flagyl's mode of action has nothing to do with attacking or disabling the parasites' flagella, as the drug's name might imply? E) 2, 3, and 4 Answer: E
Oviparous (egg-laying) animals have internal fertilization (sperm cells encounter eggs within the female's body). Yolk and/or albumen is (are) provided to the embryo, and a shell is then deposited around the embryo and its food source. Eggs are subsequently deposited in an environment that promotes their further development, or are incubated by one or both parents.
The yolk and/or albumen of an animal egg is what type of angiosperm analog? Answer: A) endosperm The shell of an animal egg is what type of angiosperm analog? Answer: E) integuments The internal fertilization that occurs prior to shell deposition is what type of angiosperm analog? Answer: B) pollen tube and sperm nuclei The dispersal and/or nurture of young after hatching from the egg is what type of angiosperm analog? Answer: D) fruit
A biology student hiking in a forest happens upon an erect, 15-cm-tall plant that bears microphylls and a strobilus at its tallest point. When disturbed, the cone emits a dense cloud of brownish dust. A pocket magnifying glass reveals the dust to be composed of tiny spheres with a high oil content.
This student has probably found a(n) E) lycophyte sporophyte. Answer: E Besides oil, what other chemical should be detected in substantial amounts upon chemical analysis of these small spheres? A) sporopollenins Answer: A This organism probably belongs to the same phylum as the B) club mosses, quillworts, and spike mosses. Answer: B A dissection of the interior of this organism's stem should reveal A) lignified vascular tissues. Answer: A
Big Bend National Park in Texas is mostly Chihuahuan desert, where rainfall averages about 10 inches per year. Yet, it is not uncommon when hiking in this bone-dry desert to encounter mosses and ferns. One such plant is called "flower of stone." It is not a flowering plant, nor does it produce seeds. Under arid conditions, its leaflike structures curl up. However, when it rains, it unfurls its leaves, which form a bright green rosette on the desert floor. Consequently, it is sometimes called the "resurrection plant." At first glance, it could be a fern, a true moss, or a spike moss.
What feature of both true mosses and ferns makes it most surprising that they can survive for many generations in dry deserts? A) flagellated sperm Answer: A Which of the following features is most important in order for true mosses and ferns to survive and reproduce in the desert? C) either that their gametophytes grow close together, or that they be hermaphroditic Answer: C Which of the following characteristics is (are) possessed in common by true mosses, ferns, and spike mosses, and therefore becomes useless at helping to determine to which of these groups flower of stone belongs? 1. a sporophyte generation that is dominant 2. true leaves and roots 3. flagellated sperm 4. strobili 5. alternation of generations D) 3 and 5 Answer: D Upon closer inspection of the leaves of flower of stone, one can observe tiny, cone-like structures. Each cone-like structure emits spores of two different sizes. Based on this information, which of the following can be properly inferred about flower of stone? 1. It is heterosporous. 2. It is a fern. 3. The cone-like structures are sori. 4. It is a lycophyte. 5. It has separate male and female gametophytes. D) 1, 4, and 5 Answer: D Upon closer inspection of the leaves of flower of stone, one can observe tiny, cone-like structures. Each cone-like structure emits spores of two different sizes. Consequently, which of the following is the closest living relative of flower of stone? B) club moss Answer: B Upon closer inspection of the leaves of flower of stone, one can observe tiny, cone-like structures. Each cone-like structure emits spores of two different sizes. Consequently, flower of stone should be expected to possess which other characteristics? 1. a gametophyte generation that is dominant 2. lignified vascular tissues 3. microphylls 4. filamentous rhizoids, but not true roots 5. spores that are diploid when mature C) 2 and 3 Answer: C In which combination of locations would one who is searching for the gametophytes of flower of stone have the best chance of finding them? 1. moist soil 2. underground, nourished there by symbiotic fungi 3. south- or west-facing slopes 4. permanently shady places 5. far from any flower of stone sporophytes C) 1, 2, and 4 Answer: C
The cycads, a mostly tropical phylum of gymnosperms, evolved about 300 million years ago and were dominant forms during the Age of the Dinosaurs. Though their sperm are flagellated, their ovules are pollinated by beetles. These beetles get nutrition (they eat pollen) and shelter from the microsporophylls. Upon visiting megasporophylls, the beetles transfer pollen to the exposed ovules. In cycads, pollen cones and seed cones are borne on different plants. Cycads synthesize neurotoxins, especially in the seeds, that are effective against most animals, including humans.
Which feature of cycads distinguishes them from most other gymnosperms? 1. They have exposed ovules. 2. They have flagellated sperm. 3. They are pollinated by animals. A) 1 only B) 2 only C) 3 only D) 2 and 3 E) 1, 2, and 3 Answer: D Which feature of cycads makes them similar to many angiosperms? 1. They have exposed ovules. 2. They have flagellated sperm. 3. They are pollinated by animals. A) 1 only B) 2 only C) 3 only D) 2 and 3 E) 1, 2, and 3 Answer: C If the beetles survive by consuming cycad pollen, then whether the beetles should be considered mutualists with, or parasites of, the cycads depends upon A) the extent to which their overall activities affect cycad reproduction. B) the extent to which the beetles are affected by the neurotoxins. C) the extent to which the beetles damage the cycad flowers. D) the distance the beetles must travel between cycad microsporophylls and cycad megasporophylls. Answer: A On the Pacific island of Guam, large herbivorous bats called "flying foxes" commonly feed on cycad seeds, a potent source of neurotoxins. The flying foxes do not visit male cones. Consequently, what should be true? A) The flying foxes are attracted to cycad fruit, and eat the enclosed seeds only by accident. B) Flying foxes are highly susceptible to the effects of the neurotoxins. C) The flying foxes assist the beetles as important pollinating agents of the cycads. D) Flying foxes can be dispersal agents of cycad seeds if the seeds sometimes get swallowed whole (in other words, without getting chewed). Answer: D If one were to erect a new taxon of plants that included all plants that are pollinated by animals, and only plants that are pollinated by animals, then this new taxon would be A) monophyletic. B) paraphyletic. C) polyphyletic. D) identical in composition to the phylum Anthophyta. E) identical in composition to the phylum Cycadophyta. Answer: C
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 gathers 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? E) mixotroph Answer: E Which term accurately describes the behavior of Paramecium species that lack zoochlorellae in an aquarium with light coming from one side only? D) negative phototaxis Answer: D Which term best describes the symbiotic relationship of well-fed P. bursaria to their zoochlorellae? A) mutualistic Answer: A The motility that permits P. bursaria to move toward a light source is provided by D) many cilia. Answer: D 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? B) abundant light, abundant bacterial prey Answer: B 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? B) commensalistic Answer: B Theoretically, P.bursaria can obtain zoochlorella 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 what is true? C) The zoochlorellae also reproduced asexually, at a fairly constant rate over time. Answer: C
If intelligent extraterrestrials visited Earth 475 million years ago, and then again 300 million years ago (at the close of the Carboniferous period), what trends would they have noticed in Earth's terrestrial vegetation over this period? 1.
a trend from dominant gametophytes to dominant sporophytes 2. a trend from sporangia borne on modified leaves (sporophylls) to sporangia borne on stalks (seta) 3. a trend from no true leaves, to microphylls, to megaphylls 4. a trend from soil-surface-hugging plants to "overtopping" plants 5. a trend toward increased lignification of conducting systems D) 1, 3, 4, and 5 Answer: D
Assuming that they all belong to the same plant, arrange the following structures from largest to smallest. 1.
antheridia 2. gametes 3. gametophytes 4. gametangia D) 3, 4, 1, 2 Answer: D