Chapter 31

soredia

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?

cytoplasmic streaming in hyphae

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?

the hypothesis that a toxin secreted by Jl cells kills Bd cells when both are present together on frog skin

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?

similar nucleus and less cytoplasm than the mother cell

After cytokinesis occurs in budding yeasts, the daughter cell has a _____.

by flagella

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?

4 → 1 → 5 → 2 → 3

Arrange the following in order from largest to smallest, assuming that they all come from the same fungus. 4. mycelium 1. basidiocarp 5. gill 2. basidium 3. basidiospore

3 → 2 → 4 → 1

Arrange the following in order from largest to smallest. 3. ascomycete 2. ascocarp 4. ascus 1. ascospore

It should produce fewer fermentation products per unit time.

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?

D

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

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

D

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?

plasmogamy

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

No effect is predicted, because the dominant species is unaffected by AMF diversity.

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

Carex flacca (graph a)

Based on the graphs in the figure above, which of the following plant species is most likely NOT to form mycorrhizal associations?

If a single mycorrhizal fungus formed symbiotic associations with more than one tree, carbon could travel from one plant to another.

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

no AMF are present

Based on the van der Heijden et al. (1998) graphs in the figure above, 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 _____.

This fungal group can break down the tough lignin, which cannot be harnessed for energy, to get to the more useful cellulose.

Basidiomycetes are the only fungal group capable of synthesizing lignin peroxidase. What advantage does this group of fungi have over other fungi because of this capability?

are the group of fungi that have, at present, no known sexual stage

Deuteromycetes _____.

colonization of land and loss of flagellated cells

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?

The larger surface area allows for more material to be transported through the cell membrane.

Fungi have an extremely high surface-area-to-volume ratio. What is the advantage of this to an organism that gets most of its nutrition through absorption?

the "9 + 2 pattern" of microtubules

Given the eukaryotic structures they lack, it should be expected that microsporidians also lack _____.

Their conversion from yeast to hyphal morphology allows such fast growth that the body's defenses are at least temporarily overwhelmed.

Humans have immune systems in which lymph nodes are important, because many phagocytes and lymphocytes reside there. Given that a successful infection by S. schenkii damages lymph nodes themselves, which of the following is most probable?

1 or 4

If Bd cannot grow properly at temperatures above 28°C (82°F), then, assuming the amphibians can survive, in which time or place should the chytrid infection proceed most rapidly? 1. cooler months 4. higher altitudes

100, carried on 7 chromosomes

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?

prokaryotes

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?

lichens are not purely mutualistic relationships

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 _____.

tree stump

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"?

This plant forms multiple AMF associations, growing best with increased fungal diversity.

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

results in heterokaryotic or dikaryotic cells

In most fungi, karyogamy does not immediately follow plasmogamy, which consequently _____.

skin mycoses

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?

Radioactively labeled sugars produced by plants eventually show up in the fungi with which they are associated.

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?

leaf mesophyll

Mycorrhizae are to the roots of vascular plants as endophytes are to vascular plants' _____.

by providing the embryos with some of the organic nutrients they have absorbed

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?

2 or 3

Plasmogamy can directly result in which of the following? 2. heterokaryotic cells 3. dikaryotic cells

Carbon-14 is found in the Douglas fir seedling's tissues and carbon-13 in the birch.

Refer to 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.]

Either carbon-13 or carbon-14 is found in the cedar seedling's tissues.

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.]

the cedar seedling, because it forms arbuscular mycorrhizae

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

deuteromycetes

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?

More 13C would be found in the birch than in the Douglas fir.

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 was placed over the birch seedlings and the cedar, and the Douglas fir was left in full sun, what result could Simard and colleagues expect?

mutualistic

Some fungal species can kill herbivores while feeding off of sugars from its plant host. What type of relationship does this fungus have with its host?

2 and 5

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 two of these are conclusions make sense on the basis of this information? 2. S. schenkii should be reclassified. 5. S. schenkii yeasts belonging to two different mating strains were introduced by the same thorn prick.

hyphae

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

an extensive surface area well suited for invasive growth and absorptive nutrition

The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to _____.

Does S. schenkii rely on animal infection to complete some part of its life cycle, or is the infection merely opportunistic?

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?

gap junctions — plasmodesmata

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?

1, 2, and 4

The microsporidian 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 how many of the following statements should be true? 1. Brachiola should kill the mosquitoes before the malarial parasite they carry reaches maturity. 2. The microsporidian should not be harmful to other insects. 4. The subsequent decline in anopheline mosquitoes should not significantly disrupt human food resources or other food webs.

by convergent evolution

The multicellular condition of animals and fungi seems to have arisen _____.

Both groups use chitin for support.

What do fungi and arthropods have in common?

Bromus erectus is unaffected by AMF diversity.

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

C

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

fungal enzymes

When a mycelium infiltrates an unexploited source of dead organic matter, what are most likely to appear within the food source soon thereafter?

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.

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?

fungicide might also kill mycorrhizae

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 _____.

flagellated spores

Which feature seen in chytrids supports the hypothesis that they diverged earliest in fungal evolution?

A

Which location is nearest to basidiocarps?

Photosynthetic cells are surrounded by fungal hyphae.

Which of the following best describes the physical relationship of the partners involved in lichens?

lichens

Which of the following has the LEAST affiliation with all of the others?

Fungi secrete extracellular enzymes that can break down large molecules.

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

Bromus erectus is the dominant plant species.

Why does total biomass (graph e in the figure above) not vary with AMF diversity?

Chytrids

You observe the gametes of a fungal species under the microscope and realize that they resemble animal sperm. To which of the following group does the fungus belong?