Ch 31 Flashcards


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1

1) Use the following information to answer the question.

In the United States and Canada, bats use one of two strategies to survive winter. They either migrate south, or they hibernate. Recently, those that hibernate seem to have come under attack by a fungus, Geomyces destructans (Gd), an attack that is occurring from Missouri to New England, Canada, and even the state of Washington. Many infected bats have a delicate, white filamentous mat on their muzzles, which is referred to as white-nose syndrome (WNS). The fungus invades the bat tissues, causes discomfort, and awakens the bat from its hibernation. The bat fidgets and wastes calories, using up its stored fat. The bat then behaves abnormally, leaving its cave during daytime in winter to search for food. Their food, primarily insects, is scarce during the winter, and the bats ultimately starve to death. Since 2006, it is estimated that over six million bats have perished from WNS.

The Gd mat on the fur of the bats should be expected to consist of ________.

A) hyphae
B) haustoria
C) yeasts

D) basidia

A

2

2) What do fungi and arthropods have in common?
A) The haploid state is dominant in both groups.
B) Both groups are predominantly autotrophs that produce their own food.

C) Both groups use chitin for support.
D) Both groups have cell walls.

C

3

3) Fungi have an extremely high surface-to-volume ratio. What is the advantage of this characteristic to an organism that gets most of its nutrition through absorption?
A) The high ratio allows for more material to be acquired from the surroundings and transported through the cell membrane.
B) The lower volume prevents the cells from drying out too quickly, which can interfere with absorption.
C) This high ratio creates more room inside the cells for additional organelles involved in absorption.
D) This high ratio means that fungi have a thick, fleshy structure that allows the fungi to store more of the food it absorbs.

A

4

9) 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) flowering plants

B) protists
C) prokaryotes
D) grasses

C

5

10) 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) fungal enzymes

C) increased oxygen levels
D) larger bacterial populations

B

6

11) 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?
A) karyogamy

B) mycelial flagella
C) breezes distributing spores
D) cytoplasmic streaming in hyphae

D

7

12) 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) lichens growing on the vines' branches are not harmed
C) fungicide might also kill mycorrhizae
D) sheeting is transparent so that photosynthesis can continue

C

8

13) 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) the potential to inhabit almost all terrestrial habitats

C) the increased probability of contact between different mating types
D) an extensive surface area well suited for invasive growth and absorptive nutrition

D

9

14) Some fungal species live in plants and can kill herbivores that feed on the plant. What type of relationship does this fungus have with its host?
A) parasitic
B) mutualistic

C) commensal
D) predatory

B

10

23) Some companies advertise and sell mycorrhizae to home gardeners and commercial farms, claiming that the presence of mycorrhizae improves plant growth and survival. If the company conducted experiments on plants with and without mycorrhizae, which of the following measurements would support their claim?

A) smaller apple size in plants with mycorrhizae than in plants without mycorrhizae
B) increased production of corn ears in plants with mycorrhizae than in plants without mycorrhizae
C) increased need for fertilizer in plants with mycorrhizae than in plants without mycorrhizae

D) increased mortality in plants with mycorrhizae than in plants without mycorrhizae

B

11

24) Some nematode worms suck plant juices from the roots of plants and are economically important agricultural pests. Some fungi are usually decomposers of plant material, but some trap and kill nematodes at times. Arthrobotrys traps and kills nematodes, especially when they lack nitrogen sources. These two facts suggest that farmers could find Arthrobotrys an important tool in combating nematode infestations. Which of the following research questions would make a good starting point for developing such a defense against plant-sucking nematodes?

A) Does nitrogen fertilization of crops affect the likelihood that Arthrobotrys will trap and kill nematodes?
B) Do nitrogen-fixing bacteria provide nitrogen to the fungi?
C) What is the evolutionarily oldest method of trapping nematodes?

D) What mechanisms do nematodes have that could allow them to escape from Arthrobotrys?

A

12

25) At which stage of a basidiomycete's life cycle would reproduction be halted if an enzyme that prevented the fusion of hyphae was introduced?
A) fertilization
B) karyogamy

C) plasmogamy
D) germination

C

13

26) Deuteromycetes ________.
A) represent the phylum in which all the fungal components of lichens are classified

B) are the group of fungi that have, at present, no known sexual stage
C) are the group that includes molds, yeasts, and lichens
D) include the imperfect fungi that lack hyphae

B

14

27) Use the following information to answer the question.

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.

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?
A) zygomycetes
B) glomeromycetes

C) basidiomycetes
D) deuteromycetes

D

15

28) Plasmogamy can directly result in which of the following?

A) cells with a single haploid nucleus or dikaryotic cells
B) heterokaryotic cells or dikaryotic cells
C) heterokaryotic cells or cells with two diploid nuclei

D) dikaryotic cells or cells with two diploid nuclei

B

16

29) After cytokinesis occurs in budding yeasts, the daughter cell has a ________.

A) similar nucleus and more cytoplasm than the mother cell
B) smaller nucleus and less cytoplasm than the mother cell
C) larger nucleus and less cytoplasm than the mother cell

D) similar nucleus and less cytoplasm than the mother cell

D

17

30) 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

D

18

31) 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 statements should be an accurate characterization 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 be transcriptionally less active.

C) It should have reduced motility.
D) It should have a smaller nucleus.

A

19

32) The ascomycete Brachiola gambiae parasitizes the mosquito Anopheles gambiae. Adult female mosquitoes must take blood meals for their eggs to develop, and it is while they take blood that they transmit malarial parasites to humans. Male mosquitoes drink flower nectar. If humans are to safely and effectively use Brachiola gambiae as a biological control to reduce human deaths from malaria, then which of the following statements should be correct?

A) The ascomycete should not be harmful to other insects and must be harmful to male mosquitoes, but not to female mosquitoes.
B) The ascomycete should kill the mosquitoes before the malarial parasite they carry reaches maturity and should not be harmful to other insects.
C) The ascomycete should not be harmful to other insects and should infect mosquito larvae, rather than mosquito adults.
D) The ascomycete should infect mosquito larvae, rather than mosquito adults, and the subsequent decline in anopheline mosquitoes should not significantly disrupt human food resources.

B

20

33) Why are mycorrhizal fungi superior to plants at acquiring mineral nutrition from the soil?

A) Hyphae are 100 to 1,000 times larger than plant roots.
B) Hyphae have a smaller surface area-to-volume ratio than do the hairs on a plant root.
C) Mycelia are able to grow in the direction of food.

D) Fungi secrete extracellular enzymes that can break down large molecules.

D

21

34) 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

D

22

35) 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 serial endosymbioses

B

23

36) 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
D) parasitic lifestyle

C

24

37) Chitin is a long-chain polymer derived from glucose. It strengthens cell walls of fungi and the outer covering (exoskeleton) of arthropods (including crabs, shrimps, and insects). The presence of chitin in these groups is likely due to ________.
A) secondary endoparasitism

B) horizontal gene transfer

C) paraphyletic evolution

D) convergent evolution

D

25

38) Early fungi probably formed mutualistic associations with early plants, providing nutrients to the plant and receiving energy-containing compounds. Evidence that plants' ability to form a mutualistic association with fungi is due to ancient genes includes which of the following occurrences?

A) presence of genes in the earliest fungi that showed an ability to digest cellulose and lignin

B) presence of genes for chitin in the oldest flowering plants and oldest fungi
C) fossils that show hyphae wrapped around seeds
D) restoration of the ability to form mycorrhizae with fungi by a flowering plant after biologists transferred a gene from a liverwort to the flowering plant

B

26

39) It has been hypothesized that fungi and plants have a mutualistic relationship because plants make sugars available for the fungi's use. What is the best evidence in support of this hypothesis?

A) Fungi survive better when they are associated with plants.
B) Radioactively labeled sugars produced by plants eventually show up in the fungi with which they are associated.

C) Fungi associated with plants have the ability to undergo photosynthesis and produce their own sugars, while those not associated with plants do not produce their own sugars.
D) Radioactive labeling experiments show that plants pass crucial raw materials to the fungus for manufacturing sugars.

B

27

40) You observe the gametes of a fungal species under the microscope and realize that they resemble animal sperm. To which of the following groups does the fungus belong?
A) chytrids
B) zygomycetes

C) Basidiomycota
D) Ascomycota

A

28

41) Arrange the following in order from largest to smallest.

A) ascomycete, ascocarp, ascus, ascospore
B) ascomycete, ascus, ascospore, ascocarp
C) ascocarp, ascomycete, ascus, ascospore

D) ascocarp, ascus, ascospore, ascomycete

A

29

42) Arrange the following in order from largest to smallest, assuming that they all come from the same fungus.
A) mycelium, gill, basidiocarp, basidium, basidiospore
B) gill, basidiocarp, mycelium, basidium, basidiospore

C) gill, basidiocarp, basidiospore, basidium, mycelium

D) mycelium, basidiocarp, gill, basidium, basidiospore

D

30

49) Use the following information to answer the question.

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?
A) by wind-blown spores
B) by flagella

C) by cilia
D) by hyphae

B

31

50) Use the following information to answer the question.

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.

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 to test whether this inhibition is real?
A) Inoculate uninfected amphibians with Jl, and determine whether the amphibians continue to remain uninfected by chytrids.

B) Inoculate infected amphibians with Jl and determine whether the amphibians recover from infection by chytrids.
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.
D) Take infected amphibians and assign them to two populations. Inoculate one population with a high dose of Jl; inoculate the other with a low dose of Jl. Measure the survival frequency in both populations.

C

32

51) Use the following information to answer the question.

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. However, when adult amphibian skin harbors populations of the bacterium Janthinobacterium lividum (Jl), chytrid infection seems to be inhibited.

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) A toxin secreted by Jl cells kills Bd cells when both are present together on frog skin.
B) Jl cells infect and kill Bd cells when both are present together on frog skin.
C) Jl outcompetes Bd when both are present together on a frog's skin.
D) The presence of Jl on frog skin causes a skin reaction that prevents attachment by Bd cells.

A

33

52) 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 ng on 7 chromosomes
B) 100 ng on 14 chromosomes
C) 200 ng on 7 chromosomes
D) 200 ng on 14 chromosomes

A

34

53) Which of the following characteristics would be most helpful in distinguishing among different species of fungi?
A) morphology
B) hyphae structure

C) DNA sequence
D) life cycle

C

35

59) The Neurospora genome is quite compact, lacking many of the noncoding DNA sequences that occur in humans and many other eukaryotes. Which of the following are probable benefits of the compactness of the genome?
A) The organism saves energy during cell division because fewer DNA bases must be duplicated.
B) It is more difficult for viruses to insert themselves into a compact genome.
C) There is less genetic variation that can lead to mutation.
D) The spores will be small and thus travel a greater distance.

A

36

61) Use the following information to answer the question.

Rose-picker's disease is caused by the yeast Sporothrix schenkii (S. 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.

Humans have immune systems in which lymph nodes are important, because many white blood cells (phagocytes and lymphocytes) reside there. Given that a successful infection by S. schenkii damages lymph nodes themselves, which of the following is most probable?
A) The hyphae secrete antibiotics, which increases the ability of the infected human to tolerate the fungus.

B) The fungal 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.

B

37

62) 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) soredia are asexual reproductive structures combining both the fungal and photosynthetic partners

B

38

63) 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) basidiospores

B) spores of ectomycorrhizae

C) soredia
D) yeasts

C

39

64) 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?

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 the fungi have absorbed

D) by strengthening the seed coat that surrounds each seed

C

40

65) Use the following information to answer the question.

Rose-picker's disease is caused by the yeast Sporothrix schenkii (S. 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.

Suppose that 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 of these statements make sense on the basis of this information?

A) S. schenkii produces asexual spores within lymph nodes; it continues to have no known sexual stage.
B) S. schenkii produces asexual spores within lymph nodes; S. schenkii yeasts belonging to two different mating strains were introduced by the same thorn prick.
C) S. schenkii should be reclassified; S. schenkii yeasts belonging to two different mating strains were introduced by the same thorn prick.
D) The hyphae growing in lymphatic vessels probably belonged to a different fungal species; S. schenkii yeasts belonging to two different mating strains were introduced by the same thorn prick.

C

41

66) 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) Fungi grow on rocks and trees and are covered by algae.

C

42

67) Mycorrhizae are to the roots of vascular plants as endophytes are to the ________ of vascular plants.
A) leaf mesophyll
B) stem apical meristems

C) root apical meristems
D) xylem

A

43

68) Fungi interact with many organisms in mutualistic ways. Which of the following involves a fungus that is mutualistic with another organism?
A) a fungus and a protozoan that live together as a lichen
B) a fungus that is raised by ants on leaves that the ants collect from trees and shrubs

C) a fungus that lives inside plant roots and produces toxins that kill neighboring plants

D) a fungus that produces penicillin that is used by humans to kill infectious bacteria

B

44

69) Fungi produce many compounds that humans are able to use medically. How can you account for these compounds?
A) Humans used artificial selection to develop fungi that produced specific compounds.
B) The presence of the compounds in the fungi were accidentally produced and have no function.

C) The compounds probably provide a benefit to the fungi.

D) The compounds are produced as a result of sexual reproduction and recombination.

C

45

70) Truffles are the fruiting bodies of certain fungi whose mycelium grows below ground. The truffle is also underground and can be detected by many mammals, which eat the truffle and expel the spores with their feces. Which of the following statements is likely accurate with respect to this interaction?

A) The truffle spores are probably wind dispersed.
B) Truffles produce an odor that mammals can detect and find attractive.
C) Truffles probably produce toxins that can harm the mammals that eat them.

D) Truffle fruiting bodies are important in decomposition of wood.

B

46

71) If you wanted to use fungi to improve the environment, which of the following research goals would make the most sense?
A) Discover the lignin-digesting enzymes of fungi, and use them to digest plant tissues left over from food-crop residues and produce a biofuel.
B) Discover the enzymes that the fungal partner in lichens uses to break down rock so that large rock expanses can be turned into agricultural lands.
C) Discover the enzymes that fungi use to break down plant matter and use them to increase decomposition rates in order to slow global warming.
D) Develop a strain of fungus that produces enzymes that absorb oxygen and will help slow global warming.

A

47

1) All fungi are
A) symbiotic.
B) heterotrophic.
C) flagellated.
D) decomposers.

B

48

2) Which of the following cells or structures are associated with asexual reproduction in fungi?

A) ascospores
B) basidiospores
C) zygosporangia

D) conidiophores

D

49

3) The closest relatives of fungi are thought to be the

A) animals.
B) vascular plants.
C) mosses.

D) slime molds.

A

50

4) The most important adaptive advantage associated with the filamentous nature of fungal mycelia is
A) the ability to form haustoria and parasitize other organisms.
B) the potential to inhabit almost all terrestrial habitats.

C) the increased chance of contact between mating types.
D) an extensive surface area well suited for invasive growth and absorptive nutrition.

D