Deck 31: Fungi

Question 1

Use the following information to answer the question.
Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).
Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig.A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (¹³C and ¹⁴C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant.

Figure A
Based on the idea that fungi have pores between their cell walls that allow cytoplasm to move from one end of the mycelium to the other, which of the following hypotheses is the most plausible?

A) If a single mycorrhizal fungus formed symbiotic associations with more than one tree, carbon could travel from one plant to another.
B) Parasitic fungi steal nutrients from their hosts.
C) Predatory fungi capture their prey by encircling them with hyphae, and the flowing of the cytoplasm through the pores helps the hyphae to move around the prey.
D) Fungi function as part of the global carbon cycle, not only by converting carbon from one form to another, but by physically moving it from one location to another.

Answer 1

A

Question 2

Use the following information to answer the question.
Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).
Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig.A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (¹³C and ¹⁴C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant.

Figure A
Referring to Simard et al. (1997), which design element is the control in this experiment and why?

A) the bags over the seedlings to contain the different types of carbon dioxide
B) the fact that all the seedlings are different species
C) the cedar seedling, because it is not bagged
D) the cedar seedling, because it does not form ectomycorrhizal connections with the tested fungus

Answer 2

D

Question 3

Use the following information to answer the question.
There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

A) Carex flacca (graph a)
B) Lotus corniculatus (graph b)
C) Sanguisorba officinalis (graph c)
D) Centaurium erythrea (graph d)

Answer 3

A

Question 4

Use the following information to answer the question.
Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).
Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig.A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (¹³C and ¹⁴C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant.

Figure A
Which of the following results would support Simard et al.'s (1997) hypothesis that fungi can move carbon from one plant to another? [Hypothesis: Sugars made by one plant during photosynthesis can travel through a mycorrhizal fungus and be incorporated into the tissues of another plant.]

A) Carbon-14 is found in the birch seedling's tissues and carbon-13 in the Douglas fir.
B) Carbon-14 is found in the Douglas fir seedling's tissues and carbon-13 in the birch.
C) Either carbon-13 or carbon-14 is found in the fungal tissues.
D) Either carbon-13 or carbon-14 is found in the cedar seedling's tissues.

Question 5

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

Question 6

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

Question 7

Use the following information to answer the question.
Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).
Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig.A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (¹³C and ¹⁴C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant.

Simard et al. (1997) further hypothesized that if reciprocal transfer did occur, it would be a source-sink relationship driven by photosynthetic rates. That is, if one seedling is in full sun and the other in deep shade, there will be a net movement of carbon from the seedling in full sun to the one in deep shade. If a shade were placed over the birch seedlings and the cedar, and the Douglas fir was left in full sun, what result could Simard and colleagues expect?

A) More ¹³C would be found in the birch than ¹⁴C in the Douglas fir.
B) The amounts of ¹³C and ¹⁴C would be equal in the Douglas fir and in the birch.
C) The most ¹³C would be found in the cedar.
D) The most ¹⁴C would be found in the cedar.

Question 8

There is much discussion in the media about protecting biodiversity. But does biodiversity really matter?
Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

Examine the effect of AMF species on Sanguisorba officinalis. Which of the following conclusions can be correctly drawn from the data?

A) Growth is best with AMF species D.
B) Growth is best with AMF species A.
C) Growth is best with a mixture of AMF species.
D) AMF presence had no effect on S. officinalis growth.

Question 9

Use the following information to answer the question.
Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph. Graph e is the total biomass (grams) of all 11 plant species combined; graph f is the biomass of Bromus erectus plants only, separated from the total.

What is the major difference between Bromus erectus (graph f) and the other plant species (graphs a-d) included in the study?

A) Bromus erectus grows best with a diversity of fungal partners.
B) Bromus erectus is unaffected by AMF diversity.
C) Bromus erectus does not form mycorrhizal associations.
D) Bromus erectus produces very little biomass regardless of AMF.

Question 10

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

Question 11

Use the following information to answer the question.
There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

Based on the van der Heijden et al. (1998) graphs in the figure, which of the following is the best description of the data supporting the idea that a plant species did not form mycorrhizae with a fungus? Its biomass is greatest when ________.

A) no AMF are present
B) AMF species A is present
C) AMF species B is present
D) AMF species C is present

Question 12

There is much discussion in the media about protecting biodiversity. But does biodiversity really matter?
Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph

Examine all four graphs and choose the plant species that grows best with a combination of AMF species.

A) Carex flacca (graph a)
B) Lotus corniculatus (graph b)
C) Sanguisorba officinalis (graph c)
D) Centaurium erythrea (graph d)

Question 13

Use the following information to answer the question.
Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).
Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig.A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (¹³C and ¹⁴C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant.

Figure A
Referring to Simard et al. (1997), what is the result that would most strongly refute their hypothesis? [Hypothesis: Sugars made by one plant during photosynthesis can travel through a mycorrhizal fungus and be incorporated into the tissues of another plant.]

A) No movement: Carbon-14 is found in the birch seedling's tissues and carbon-13 in the Douglas fir.
B) Reciprocal exchange: Carbon-14 is found in the Douglas fir seedling's tissues and carbon-13 in the birch.
C) Either carbon-13 or carbon-14 is found in the fungal tissues.
D) Either carbon-13 or carbon-14 is found in the cedar seedling's tissues.

Question 14

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

Question 15

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

Question 16

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

Question 17

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.

Question 18

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.

Question 19

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

Question 20

Use the following information to answer the question.
There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

In graph b in the figure, which of the following best explains the data given about Lotus corniculatus?

A) This plant grows best when AMF taxa A or C is present.
B) Lotus corniculatus does not form mycorrhizal associations.
C) Mycorrhizal fungi parasitize the plant's roots when they are present, reducing its growth.
D) This plant forms multiple AMF associations, growing best with increased fungal diversity.

Question 21

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

Question 22

Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph. Graph e is the total biomass (grams) of all 11 plant species combined; graph f is the biomass of Bromus erectus plants only, separated from the total.

Based on graphs e and f, which is the most well-supported prediction for the effect on total plant biomass if AMF diversity were increased to eight species?

A) No effect is predicted, because the dominant species is unaffected by AMF diversity.
B) Total biomass for eight species would double in comparison to that for four species.
C) Rare species would produce more biomass compared to the case when fewer AMF are present.
D) No effect is predicted, because the dominant species is non-mycorrhizal.

Question 23

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

Question 24

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

Question 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

Question 26

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?

Question 27

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

Question 28

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.

Question 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

Question 30

Use the following information to answer the question.
Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D), no AMF species (O), or all four AMF species together (A + B + C + D); and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together). The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph. Graph e is the total biomass (grams) of all 11 plant species combined; graph f is the biomass of Bromus erectus plants only, separated from the total.

What is the most likely explanation for the observation that total biomass (graph e) does not vary with AMF diversity?

A) Plant growth is unaffected by fungal diversity.
B) Most of the plants in this system do not form mycorrhizal associations.
C) Bromus erectus is the dominant plant species.
D) Lotus corniculatus is a rare species.

Question 31

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

Question 32

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.

Question 33

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

Question 34

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

Question 35

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

Question 36

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.

Question 37

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.

Question 38

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

Question 39

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

Question 40

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

Question 41

Use the information to answer the following question.
The figure 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 A-D are all 0.5 meters below the soil surface.

What is the most probable location of the oldest portion of this mycelium?

A) A
B) B
C) C
D) D

Question 42

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.

Question 43

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.

Question 44

Use the information to answer the following question.
The figure 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 A-D are all 0.5 meters below the soil surface.

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?

A) A
B) B
C) C
D) D

Question 45

Use the following information to answer the question.
The figure 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 A-D are all 0.5 meters below the soil surface.

In which of the following 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 (bloodborne) Candida infection
D) infection of lymphatic vessels

Question 46

Use the following information to answer the question.
Heterobasidion is a basidiomycete that contributes to mortality of trees. Kuhlman isolated 23 strains of Heterobasidion and applied them to 16 seedlings of 10 different tree species. Partial results of this experiment are shown in the table. (From Kuhlman, E. G. 1970. Seedling inoculations with Fomes annosus show variation in virulence and in host susceptibility. Phytopathology 60:1743-1746. https://www.apsnet.org/publications/phytopathology/backissues/Documents/1970Articles/Phyto60n12_1743.PDF)
% mortality of five host species from five Heterobasidion isolates

Which of the following conclusions can best be drawn from these results?

A) All tree species are susceptible to Heterobasidion.
B) Heterobasidion strains are equally lethal to all tree species.
C) Heterobasidion reduces mortality of some species.
D) Tree species vary in their susceptibility to Heterobasidion.

Question 47

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

Question 48

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

Question 49

Use the information to answer the following question.
The figure 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 A-D are all 0.5 meters below the soil surface.

Which location is nearest to basidiocarps?

A) A
B) B
C) C
D) D

Question 50

Use the following information to answer the question.
Along with bacteria and protozoa, some chytrid fungi live in the digestive tracts of cattle and aid in the digestion of plant matter; thus, all three groups represent potential mutualists with cattle. In an experiment designed to test how much of a contribution to cell wall digestion was made by fungi in one part of the stomach (rumen), Lee et al. fed grain to cattle and then removed samples of the rumen contents. They took these samples to the laboratory and experimentally treated them with various chemicals to produce fractions that contained (A) only fungi, (B) only bacteria, (C) only protozoa, and (D) all of the potential mutualists. They then measured the percent of the cell wall that was degraded (see the figure).

Degradation rates of cell walls extracted from Orchard grass by the monoculture system to assess the relative contributions of digestion by bacterial (square), protozoan (triangle), and fungal (diamond) systems, and all components (closed circle) as a control. The lowercase letters above the spots indicate statistical significance; mean values with different letters are significantly different (P < 0.05).
Which of the following reasons provides the best explanation for the use of a control that contained all potential mutualists? Comparison to a fraction that contained all potential mutualists allowed the researchers to ________.

A) demonstrate that their laboratory culture conditions allowed all potential mutualists to grow
B) determine how much each potential mutualist contributed to cell wall degradation
C) better mimic the conditions of the rumen
D) demonstrate that the various potential mutualists did not compete with each other

Question 51

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

Question 52

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.

Question 53

Use the following information to answer the question.
Heterobasidion is a basidiomycete that contributes to mortality of trees. Kuhlman isolated 23 strains of Heterobasidion and applied them to 16 seedlings of 10 different tree species. Partial results of this experiment are shown in the table. (From Kuhlman, E. G. 1970. Seedling inoculations with Fomes annosus show variation in virulence and in host susceptibility. Phytopathology 60:1743-1746. https://www.apsnet.org/publications/phytopathology/backissues/Documents/1970Articles/Phyto60n12_1743.PDF)
% mortality of five host species from five Heterobasidion isolates

Which of the following conclusions can best be drawn from these results?

A) All tree species are susceptible to Heterobasidion.
B) Heterobasidion strains are equally lethal to all tree species.
C) Heterobasidion strains vary in their effect on tree species.
D) Some strains of Heterobasidion reduce tree mortality.

Question 54

Use the information to answer the following question.
The figure 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 A-D are all 0.5 meters below the soil surface.

At which location is the mycelium currently absorbing the most nutrients per unit surface area, per unit time?

A) A
B) B
C) C
D) D

Question 55

Use the following information to answer the question.
Along with bacteria and protozoa, some chytrid fungi live in the digestive tracts of cattle and aid in the digestion of plant matter; thus, all three groups represent potential mutualists with cattle. In an experiment designed to test how much of a contribution to cell wall digestion was made by fungi in one part of the stomach (rumen), Lee et al. fed grain to cattle and then removed samples of the rumen contents. They took these samples to the laboratory and experimentally treated them with various chemicals to produce fractions that contained (A) only fungi, (B) only bacteria, (C) only protozoa, and (D) all of the potential mutualists. They then measured the percent of the cell wall that was degraded (see the figure).

Degradation rates of cell walls extracted from Orchard grass by the monoculture system to assess the relative contributions of digestion by bacterial (square), protozoan (triangle), and fungal (diamond) systems, and all components (closed circle) as a control. The lowercase letters above the spots indicate statistical significance; mean values with different letters are significantly different (P < 0.05).
Which of the following conclusions can be drawn correctly from the data?

A) Of all three potential mutualists, protozoa contribute the most to cell wall digestion.
B) Of all three potential mutualists, fungi contribute the least to cell wall digestion.
C) Fungi contribute as much to cell wall degradation as all the potential mutualists together.
D) The cattle did not benefit from the presence of fungi; therefore, the fungi are not mutualistic with the cattle.

Question 56

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

Question 57

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

Question 58

Use the information to answer the following question.
The figure 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 A-D are all 0.5 meters below the soil surface.

Assume that all four locations are 0.5 meters above the surface. On a breezy day with prevailing winds blowing from left to right, where should one expect to find the highest concentration of free basidiospores in an air sample?

A) A
B) B
C) C
D) D

Question 59

Use the information to answer the following question.
The figure 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 A-D are all 0.5 meters below the soil surface.

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) tree stump
B) deceased animal
C) fire pit
D) cement-capped well

Question 60

Use the following information to answer the question.
Along with bacteria and protozoa, some chytrid fungi live in the digestive tracts of cattle and aid in the digestion of plant matter; thus, all three groups represent potential mutualists with cattle. In an experiment designed to test how much of a contribution to cell wall digestion was made by fungi in one part of the stomach (rumen), Lee et al. fed grain to cattle and then removed samples of the rumen contents. They took these samples to the laboratory and experimentally treated them with various chemicals to produce fractions that contained (A) only fungi, (B) only bacteria, (C) only protozoa, and (D) all of the potential mutualists. They then measured the percent of the cell wall that was degraded (see the figure).

Degradation rates of cell walls extracted from Orchard grass by the monoculture system to assess the relative contributions of digestion by bacterial (square), protozoan (triangle), and fungal (diamond) systems, and all components (closed circle) as a control. The lowercase letters above the spots indicate statistical significance; mean values with different letters are significantly different (P < 0.05).
Predict the results if the researchers had used a control that contained no potential mutualists (negative control).

A) The negative control would have as much cell wall degradation as was shown by fungi alone.
B) The negative control would have very little cell wall degradation.
C) The negative control would have as much cell wall degradation as all three of the potential mutualists together.
D) The negative control would have more cell wall digestion than protozoans alone.

Question 61

All fungi are

A) symbiotic.
B) heterotrophic.
C) flagellated.
D) decomposers.

Question 62

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.

Question 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

Question 64

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.

Question 65

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

Question 66

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

Question 67

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.

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

Question 69

The closest relatives of fungi are thought to be the

A) animals.
B) vascular plants.
C) mosses.
D) slime molds.

Question 70

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

Question 71

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

A) ascospores
B) basidiospores
C) zygosporangia
D) conidiophores

Question 72

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.

Question 73

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.

Question 74

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.

Question 75

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.