8e Biology, (Campbell) Chapter 31 Fungi Multiple-Choice Questions 1) Which of the following do all fungi have in common? A) meiosis in basidia B) coenocytic hyphae C) sexual life cycle D) absorption of nutrients E) symbioses with algae Answer: D Topic: Concept 31.1 Skill: Knowledge/Comprehension 2) The hydrolytic digestion of which of the following should produce monomers that are aminated (i.e., have an amine group attached) molecules of beta-glucose? A) insect exoskeleton B) plant cell walls C) fungal cell walls D) A and C only E) A, B and C Answer: D Topic: Concept 31.1 Skill: Knowledge/Comprehension 3) 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? A) plants B) protists C) prokaryotes D) animals E) mutualistic fungi Answer: C Topic: Concept 31.1 Skill: Application/Analysis 4) When a mycelium infiltrates an unexploited source of dead organic matter, what are most likely to appear within the food source soon thereafter? A) fungal haustoria B) soredia C) fungal enzymes
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D) increased oxygen levels E) larger bacterial populations Answer: C Topic: Concept 31.1 Skill: Application/Analysis 5) Which of the following is a characteristic of hyphate fungi (fungi featuring hyphae)? A) They acquire their nutrients by phagocytosis. B) Their body plan is a unicellular sphere. C) Their cell walls consist mainly of cellulose microfibrils. D) They are adapted for rapid directional growth to new food sources. E) They reproduce asexually by a process known as budding. Answer: D Topic: Concept 31.1 Skill: Knowledge/Comprehension 6) 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? A) desmosomes : tonoplasts B) gap junctions : plasmodesmata C) tight junctions : plastids D) centrioles : plastids E) flagella : central vacuoles Answer: B Topic: Concept 31.1 Skill: Application/Analysis 7) What is the primary role of a mushroom's underground mycelium? A) absorbing nutrients B) anchoring C) sexual reproduction D) asexual reproduction E) protection Answer: A Topic: Concept 31.1 Skill: Knowledge/Comprehension 8) What do fungi and arthropods have in common? A) Both groups are commonly coenocytic. B) The haploid state is dominant in both groups. C) Both groups are predominantly heterotrophs that ingest their food. D) The protective coats of both groups are made of chitin. E) Both groups have cell walls.
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Answer: D Topic: Concept 31.1 Skill: Knowledge/Comprehension 9) In septate fungi, what structures allow cytoplasmic streaming to distribute needed nutrients, synthesized compounds, and organelles throughout the hyphae? A) multiple chitinous layers in cross walls B) pores in cross walls C) complex microtubular cytoskeletons D) two nuclei E) tight junctions that form in cross walls between cells Answer: B Topic: Concept 31.1 Skill: Knowledge/Comprehension 10) What accounts most directly for the extremely fast growth of a fungal mycelium? A) rapid distribution of synthesized proteins by cytoplasmic streaming B) a long tubular body shape C) the readily available nutrients from their ingestive mode of nutrition D) a dikaryotic condition that supplies greater amounts of proteins and nutrients Answer: A Topic: Concept 31.1 Skill: Knowledge/Comprehension 11) The vegetative (nutritionally active) bodies of most fungi are A) composed of hyphae. B) referred to as a mycelium. C) usually underground. D) A and B only E) A, B, and C Answer: E Topic: Concept 31.1 Skill: Knowledge/Comprehension 12) Both fungus-farming ants and their fungi can synthesize the same structural polysaccharide from the beta-glucose. What is this polysaccharide? A) amylopectin B) chitin C) cellulose D) lignin E) glycogen Answer: B Topic: Concept 31.1 Skill: Application/Analysis
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13) 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 A) fewer nuclei. B) more pores. C) less chitin. D) less cytoplasm. E) reduced cytoplasmic streaming. Answer: C Topic: Concept 31.1 Skill: Application/Analysis 14) Which of the following terms is correctly associated with fungi in general? A) sporophytes B) make only sexually produced spores C) ecologically important D) polyphyletic E) ingestive nutrition Answer: C Topic: Concept 31.1 Skill: Knowledge/Comprehension 15) Which of the following vary tremendously from each other in morphology and belong to several fungal phyla? A) lichens B) ascomycetes C) club fungi D) arbuscular mycorrhizae E) ergot fungi Answer: A Topic: Concept 31.2 Skill: Knowledge/Comprehension 16) In most fungi, karyogamy does not immediately follow plasmogamy, which consequently A) means that sexual reproduction can occur in specialized structures. B) results in multiple diploid nuclei per cell. C) allows fungi to reproduce asexually most of the time. D) results in heterokaryotic or dikaryotic cells. E) is strong support for the claim that fungi are not truly eukaryotic. Answer: D Topic: Concept 31.2 Skill: Application/Analysis
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17) If all of their nuclei are equally active transcriptionally then, in terms of the gene products they can make, the cells of both dikaryotic and heterokaryotic fungi are essentially A) haploid. B) diploid. C) alloploid. D) completely homozygous. E) completely hemizygous. Answer: B Topic: Concept 31.2 Skill: Knowledge/Comprehension 18) Which process occurs in fungi and has the opposite effect on a cell's chromosome number than does meiosis I? A) mitosis B) plasmogamy C) crossing-over D) binary fission E) karyogamy Answer: E Topic: Concept 31.2 Skill: Knowledge/Comprehension Please refer to the following information to answer the following questions. 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. 19) 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, 7 B) 100, 14 C) 200, 7 D) 200, 14 E) 400, 14 Answer: A Topic: Concept 31.2 Skill: Application/Analysis 20) What is the ploidy of a single mature ascospore? A) monoploid B) diploid C) triploid D) tetraploid
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E) polyploid Answer: A Topic: Concept 31.2 Skill: Knowledge/Comprehension 21) 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 Topic: Concept 31.2 Skill: Application/Analysis 22) Fungal cells can reproduce asexually by undergoing mitosis followed by cytokinesis. Many fungi can also prepare to reproduce sexually by undergoing A) cytokinesis followed by karyokinesis. B) binary fission followed by cytokinesis. C) plasmolysis followed by karyotyping. D) plasmogamy followed by karyogamy. E) sporogenesis followed by gametogenesis. Answer: D Topic: Concept 31.2 Skill: Knowledge/Comprehension 23) Which of the following statements is true of deuteromycetes? A) They are the second of five fungal phyla to have evolved. B) They represent the phylum in which all the fungal components of lichens are classified. C) They are the group of fungi that have, at present, no known sexual stage. D) They are the group that includes molds, yeasts, and lichens. E) They include the imperfect fungi that lack hyphae. Answer: C Topic: Concept 31.2 Skill: Knowledge/Comprehension 24) For mycelia described as heterokaryons or as being dikaryotic, which process has already occurred, and which process has not yet occurred? A) germination, plasmogamy B) karyogamy, germination C) meiosis, mitosis D) germination, mitosis
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E) plasmogamy, genetic recombination Answer: E Topic: Concept 31.2 Skill: Application/Analysis 25) A chemical secreted by a female Bombyx moth helps the male of the species locate her, at which time sexual reproduction may occur. This chemical is most similar in function to which chemicals used by sexually reproducing fungi? A) chitin B) enzymes C) lysergic acids D) aflatoxins E) pheromones Answer: E Topic: Concept 31.2 Skill: Application/Analysis 26) Which of the following is characterized by the lack of an observed sexual phase in its members' life cycle? A) Glomeromycota B) Basidiomycota C) Chytridiomycota D) Deuteromycota E) Zygomycota Answer: D Topic: Concept 31.2 Skill: Knowledge/Comprehension 27) A biologist is trying to classify a newly discovered fungus on the basis of the following characteristics: filamentous appearance, reproduction by asexual spores, no apparent sexual phase, and parasitism of woody plants. If asked for advice, to which group would you assign this new species? A) Deuteromycota B) Zygomycota C) Ascomycota D) Basidiomycota E) Glomeromycota Answer: A Topic: Concept 31.2 Skill: Application/Analysis 28) Which of these structures are most likely to be a component of both chytrid zoospores and motile animal cells? A) cilia
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B) flagella C) pseudopods D) heterokaryons E) haustoria Answer: B Topic: Concept 31.3 Skill: Knowledge/Comprehension 29) 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? A) presence of "coal forests" and change in mode of nutrition B) periods of drought and presence of filamentous body shape C) predominance in swamps and presence of cellulose in cell walls D) colonization of land and loss of flagellated cells E) continental drift and mode of spore dispersal Answer: D Topic: Concept 31.3 Skill: Knowledge/Comprehension 30) Which of the following characteristics is shared by both chytrids and other kinds of fungi? A) presence of flagella B) zoospores C) autotrophic mode of nutrition D) cell walls of cellulose E) nucleotide sequences of several genes Answer: E Topic: Concept 31.3 Skill: Knowledge/Comprehension 31) The multicellular condition of animals and fungi seems to have arisen A) due to common ancestry. B) by convergent evolution. C) by inheritance of acquired traits. D) by natural means, and is a homology. E) by serial endosymbioses. Answer: B Topic: Concept 31.3 Skill: Knowledge/Comprehension 32) 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. B) It should produce ribosomal RNA at a slower rate.
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C) It should be transcriptionally less active. D) It should have reduced motility. E) It should have a smaller nucleus. Answer: A Topic: Concept 31.3 Skill: Application/Analysis 33) This phylum contains organisms that most closely resemble the common ancestor of fungi and animals: A) Zygomycota B) Ascomycota C) Basidiomycota D) Glomeromycota E) Chytridiomycota Answer: E Topic: Concept 31.4 Skill: Knowledge/Comprehension 34) This phylum formerly included the members of the new phylum Glomeromycota: A) Zygomycota B) Ascomycota C) Basidiomycota D) Glomeromycota E) Chytridiomycota Answer: A Topic: Concept 31.4 Skill: Knowledge/Comprehension 35) Members of this phylum produce two kinds of haploid spores, one kind being asexually produced conidia: A) Zygomycota B) Ascomycota C) Basidiomycota D) Glomeromycota E) Chytridiomycota Answer: B Topic: Concept 31.4 Skill: Knowledge/Comprehension 36) This phylum contains the mushrooms, shelf fungi, and puffballs: A) Zygomycota B) Ascomycota C) Basidiomycota D) Glomeromycota
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E) Chytridiomycota Answer: C Topic: Concept 31.4 Skill: Knowledge/Comprehension 37) Members of this phylum form arbuscular mycorrhizae: A) Zygomycota B) Ascomycota C) Basidiomycota D) Glomeromycota E) Chytridiomycota Answer: D Topic: Concept 31.4 Skill: Knowledge/Comprehension 38) You have been given the assignment of locating living members of the phylum Glomeromycota. Where is the best place to look for these fungi? A) between the toes of a person with "athlete's foot" B) in stagnant freshwater ponds C) the roots of vascular plants D) growing on rocks and tree bark E) the kidneys of mammals Answer: C Topic: Concept 31.4 Skill: Application/Analysis 39) Zygosporangia are to zygomycetes as basidia are to A) basal fungi. B) chytrids. C) sac fungi. D) basidiospores. E) club fungi. Answer: E Topic: Concept 31.4 Skill: Knowledge/Comprehension 40) What are the sporangia of the bread mold Rhizopus? A) asexual structures that produce haploid spores B) asexual structures that produce diploid spores C) sexual structures that produce haploid spores D) sexual structures that produce diploid spores E) vegetative structures with no role in reproduction Answer: A
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Topic: Concept 31.4 Skill: Knowledge/Comprehension 41) The gray-black, filamentous, haploid mycelium growing on bread is most likely what kind of organism? A) chytrid B) ascomycete C) basidiomycete D) deuteromycete E) zygomycete Answer: E Topic: Concept 31.4 Skill: Knowledge/Comprehension 42) The ascomycetes get their name from which aspect of their life cycle? A) vegetative growth form B) asexual spore production C) sexual structures D) shape of the spore E) type of vegetative mycelium Answer: C Topic: Concept 31.4 Skill: Knowledge/Comprehension 43) Which of these paired fungal structures are structurally and functionally most alike? A) conidia and basidiocarps B) sporangia and hyphae C) soredia and gills D) haustoria and arbuscules E) zoospores and mycelia Answer: D Topic: Concept 31.4 Skill: Knowledge/Comprehension 44) 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? A) zygomycete B) ascomycete C) deuteromycete D) chytrid E) basidiomycete Answer: B Topic: Concept 31.4 Skill: Knowledge/Comprehension
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45) Which has the least affiliation with all of the others? A) Glomeromycota B) mycorrhizae C) lichens D) arbuscules E) mutualistic fungi Answer: C Topic: Concept 31.4 Skill: Knowledge/Comprehension 46) Which of these is a fungal structure that is usually associated with asexual reproduction? A) zygosporangium B) basidium C) conidiophore D) ascus E) antheridium Answer: C Topic: Concept 31.4 Skill: Knowledge/Comprehension 47) Arrange the following from largest to smallest: 1. ascospore 2. ascocarp 3. ascomycete 4. ascus A) 3 4 2 1 B) 3 2 4 1 C) 3 4 1 2 D) 2 3 4 1 E) 2 4 1 3 Answer: B Topic: Concept 31.4 Skill: Knowledge/Comprehension 48) In which phylum are mushrooms and toadstools A) classified? Basidiomycota B) Ascomycota C) Deuteromycota D) Zygomycota E) Chytridiomycota Answer: A Topic: Concept 31.4 Skill: Knowledge/Comprehension
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49) 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 A) 4, 5, 1, 2, 3 B) 5, 1, 4, 2, 3 C) 5, 1, 4, 3, 2 D) 5, 1, 3, 2, 4 E) 4, 1, 5, 2, 3 Answer: E Topic: Concept 31.4 Skill: Knowledge/Comprehension 50) Mushrooms with gills have meiotically produced spores located in or on A) asci. B) conidiophores. C) basidia. D) soredia. E) zygosporangia. Answer: C Topic: Concept 31.4 Skill: Knowledge/Comprehension 51) Among sac fungi, which of these correctly distinguishes ascospores from conidia? A) ascospores are diploid, conidia are haploid B) ascospores are produced only by meiosis, conidia are produced only by mitosis C) ascospores have undergone genetic recombination during their production, conidia have not D) ascospores are larger, conidia are smaller E) ascospores will germinate into haploid hyphae, conidia will germinate into diploid hyphae Answer: C Topic: Concept 31.4 Skill: Knowledge/Comprehension 52) 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 these accounts for the fungal movement, as described here? A) karyogamy B) mycelial flagella C) alternation of generations D) breezes distributing spores E) cytoplasmic streaming in hyphae
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Answer: E Topic: Concept 31.4 Skill: Application/Analysis 53) In what structures do both Penicillium and Aspergillus produce asexual spores? A) asci B) zygosporangia C) rhizoids D) gametangia E) conidiophores Answer: E Topic: Concept 31.4 Skill: Knowledge/Comprehension Figure 31.1 below depicts the outline of a large fairy ring that has appeared overnight in an open meadow, as viewed from above. The fairy ring represents the furthest advance of this mycelium through the soil. Locations AD are all 0.5 meters below the soil surface. Responses may be used once, more than once, or not at all.
Figure 31.1 54) What is the most probable location of the oldest portion of this mycelium? Answer: C Topic: Concept 31.4 Skill: Application/Analysis 55) Which location is nearest to basidiocarps? Answer: A Topic: Concept 31.4 Skill: Application/Analysis 56) At which location is the mycelium currently absorbing the most nutrients per unit surface area, per unit time?
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Answer: A Topic: Concept 31.4 Skill: Application/Analysis 57) At which location should one find the lowest concentration of fungal enzymes, assuming that the enzymes do not diffuse far from their source, and that no other fungi are present in this habitat? Answer: D Topic: Concept 31.4 Skill: Application/Analysis 58) Assume now that all four locations are 0.5 m above the surface. On a breezy day with prevailing wings blowing from left to right, where should one expect to find the highest concentration of free basidiospores in an air sample? Answer: D Topic: Concept 31.4 Skill: Application/Analysis 59) In which of these human mycoses should one expect to find a growth pattern most similar to that of the mycelium that produced the fairy ring? A) skin mycoses B) coccidiomycosis (lung infection) C) systemic (blood-borne) Candida infection D) Sporothrix infection of lymphatic vessels E) Tinea tonsurans infection limited to interior of hair shafts Answer: A Topic: Concept 31.4 Skill: Application/Analysis 60) If the fungus that produced the fairy ring can also produce arbuscules, then which of the following is most likely to be buried at location "C"? A) septic tank B) tree stump C) deceased animal D) fire pit E) cement-capped well Answer: B Topic: Concepts 31.4, 31.5 Skill: Application/Analysis 61) Chemicals, secreted by soil fungi, that inhibit the growth of bacteria, are known as A) antibodies. B) aflatoxins.
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C) hallucinogens. D) antigens. E) antibiotics. Answer: E Topic: Concept 31.5 Skill: Knowledge/Comprehension 62) Lichens are symbiotic associations of fungi and A) mosses. B) cyanobacteria. C) green algae. D) either A or B E) either B or C Answer: E Topic: Concept 31.5 Skill: Knowledge/Comprehension 63) Lichens sometimes reproduce asexually using A) coenocytic fungal hyphae located within photosynthetic cells. B) the fruiting bodies of fungi. C) flagellated, conjoined spores of both the fungus and alga. D) specialized conidiophores. E) small clusters of fungal hyphae surrounding photosynthetic cells. Answer: E Topic: Concept 31.5 Skill: Knowledge/Comprehension 64) In both lichens and mycorrhizae, what does the fungal partner provide to its photosynthetic partner? A) carbohydrates B) fixed nitrogen C) antibiotics D) water and minerals E) protection from harmful UV Answer: D Topic: Concept 31.5 Skill: Knowledge/Comprehension 65) The symbiotic associations involving roots and soil fungi are considered A) parasitic. B) mutualistic. C) commensal. D) harmful to the plant partner. E) the beginning stages of the formation of soil.
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Answer: B Topic: Concept 31.5 Skill: Knowledge/Comprehension 66) If all mycorrhizae were somehow disrupted, then which of the following would be true? A) There would be fewer infectious diseases. B) We wouldn't have any antibiotics. C) There would be no mushrooms for pizza. D) Most vascular plants would be stunted in their growth. E) Cheeses like blue cheese or Roquefort would not exist. Answer: D Topic: Concept 31.5 Skill: Knowledge/Comprehension 67) Which of the following best describes the physical relationship of the partners involved in lichens? A) Fungal cells are enclosed within algal cells. B) Lichen cells are enclosed within fungal cells. C) Photosynthetic cells are surrounded by fungal hyphae. D) The fungi grow on rocks and trees and are covered by algae. E) Algal cells and fungal cells mix together without any apparent structure. Answer: C Topic: Concept 31.5 Skill: Knowledge/Comprehension 68) 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 A) algae and cyanobacteria are autotrophic. B) lichens are not purely mutualistic relationships. C) algae require maximal contact with the fungal partner in order to grow at optimal rates. D) fungi get all of the nutrition they need via the "leakiness" of photosynthetic partners. E) soredia are asexual reproductive structures combining both the fungal and photosynthetic partners. Answer: B Topic: Concept 31.5 Skill: Application/Analysis 69) How are the vascular plants that are involved in mycorrhizae and the photosynthetic cells that are involved in lichens alike? A) They provide organic nutrients to fungal partners. B) They secrete acids that keep the fungal partner from growing too quickly. C) They are in intimate associations with chytrids. D) They are digested by fungal enzymes while still alive.
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E) They contain endosymbiotic fungi. Answer: A Topic: Concept 31.5 Skill: Knowledge/Comprehension 70) 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 A) fungicide might also kill the native yeasts residing on the surfaces of the grapes. B) fungicide isn't also harmful to insect pests. C) lichens growing on the vines' branches are not harmed. D) fungicide might also kill mycorrhizae. E) sheeting is transparent so that photosynthesis can continue. Answer: D Topic: Concept 31.5 Skill: Application/Analysis 71) Which term below refers to symbiotic relationships that involve fungi living between the cells in plant leaves? A) pathogens B) endosymbioses C) endophytes D) lichens E) mycorrhizae Answer: C Topic: Concept 31.5 Skill: Knowledge/Comprehension 72) 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. B) It was probably a red alga. C) It was probably a member of the domain Bacteria. D) It was probably a heterotrophic prokaryote. E) It was probably infected by bacteriophage. Answer: A Topic: Concept 31.5 Skill: Application/Analysis 73) 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? A) They are currently classified among the deuteromycetes. B) They do not form heterokaryons.
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C) Their spores are produced by mitosis. D) Only A and B are correct. E) A, B, and C are correct. Answer: E Topic: Concept 31.5 Skill: Knowledge/Comprehension 74) Both fungus-derived antibiotics and hallucinogens used by humans probably evolved in fungi as a means to A) reduce competition for nutrients. B) help humanity survive. C) promote their ingestion of foodstuffs. D) eliminate other fungi. E) discourage animal predators. Answer: A Topic: Concept 31.5 Skill: Knowledge/Comprehension 75) 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? A) basiodiospores B) spores of ectomycorrhizae C) soredia D) yeasts E) leaves (as food for fungus-farming ants) Answer: C Topic: Concept 31.5 Skill: Application/Analysis 76) Mycorrhizae are to the roots of vascular plants as endophytes are to vascular plants' A) leaf mesophyll. B) stem apical meristems. C) root apical merisems D) xylem. E) waxy cuticle. Answer: A Topic: Concept 31.5 Skill: Knowledge/Comprehension 77) Which of the following conditions is caused by a fungus that is accidentally consumed along with rye flour? A) ergotism B) athlete's foot
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C) ringworm D) candidiasis (Candida yeast infection) E) coccidioidomycosis Answer: A Topic: Concept 31.5 Skill: Knowledge/Comprehension 78) 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 these represents the most likely means by which fungi might assist in seed germination, given what the seeds lack? A) by transferring some chloroplasts to the embryo in each seed B) by providing the seeds with water and minerals C) by providing the embryos with some of the organic nutrients they have absorbed D) by strengthening the seed coat that surrounds each seed Answer: C Topic: Concept 31.5 Skill: Application/Analysis The following questions are based on the description below. 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 drains. 79) 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? A) Do these yeasts perform fermentation while growing on the rose-bush thorns, or do they wait until inside a human host? B) Does S. schenkii rely on animal infection to complete some part of its life cycle, or is the infection merely opportunistic? C) Are the hyphae in lymphatic vessels septate, or are they coenocytic? D) Is S. schenkii best described as a decomposer, parasite, pathogen, or mutualist of humans? E) Being a yeast, does S. schenkii perform the process of budding? Answer: B Topic: Concept 31.5 Skill: Synthesis/Evaluation 80) 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.
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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. A) 1 and 3 B) 1 and 5 C) 2 and 3 D) 2 and 5 E) 4 and 5 Answer: D Topic: Concept 31.5 Skill: Synthesis/Evaluation 81) Humans have immune systems in which lymph nodes are important, because many phagocytes and lymphocytes reside therein. Given that a successful infection by S. schenkii damages lymph nodes themselves, which of these is most probable? A) The hyphae secrete antibiotics, which increases the ability of the infected human to tolerate the fungus. B) Their conversion from yeast to hyphal morphology allows such fast growth that the body's defenses are at least temporarily overwhelmed. C) Defensive cells of humans cannot detect foreign cells that are covered with cell walls composed of cellulose. D) Given that most fungal pathogens attack plants, human defenses are simply not adapted to seek out and destroy fungi. E) Given that most fungal pathogens of humans infect only the skin, human defenses are not adapted to seek out and destroy systemic fungal infections. Answer: B Topic: Concept 31.5 Skill: Application/Analysis Self-Quiz Questions 1) All fungi share which of the following characteristics? A) symbiotic B) heterotrophic C) flagellated D) pathogenic E) act as decomposers Answer: B 2) Which feature seen in chytrids supports the hypothesis that they diverged earliest in fungal evolution? A) the absence of chitin within the cell wall B) coenocytic hyphae C) flagellated spores
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D) formation of resistant zygosporangia E) parasitic lifestyle Answer: C 3) Which of the following cells or structures are associated with asexual reproduction in fungi? A) ascospores B) basidiospores C) zygosporangia D) conidiophores E) ascocarps Answer: D 4) The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to A) the ability to form haustoria and parasitize other organisms. B) avoiding sexual reproduction until the environment changes. C) the potential to inhabit almost all terrestrial habitats. D) the increased probability of contact between different mating types. E) an extensive surface area well suited for invasive growth and absorptive nutrition. Answer: E 5) The photosynthetic symbiont of a lichen is often a(n) A) moss. B) green alga. C) brown alga. D) ascomycete. E) small vascular plant. Answer: B 6) Among the organisms listed here, which are thought to be the closest relatives of fungi? A) animals B) vascular plants C) mosses D) brown algae E) slime molds Answer: A
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