Deck 29: Fungi

Question 1

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?

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

The question(s) below refer to the following phylogenetic trees.
Which tree depicts the microsporidians as a sister group of the fungi, rather than as a fungus?

A) I
B) II
C) III
D) IV

Answer 2

D

Question 3

Long, branching fungal filaments are called ________.

A) roots
B) ascus
C) septa
D) mycelia
E) hyphae

Answer 3

E

Question 4

Why is it more difficult to treat fungal infections than bacterial infections in humans?

A) Fungi are larger organisms than bacteria and thus require stronger drugs to stop an infection.
B) Most fungi are multicellular and thus the drugs required to treat a fungal infection must be able to kill several types of cells; bacteria, on the other hand, are unicellular and thus simpler to kill.
C) Fungal and animal cells and proteins are similar. Thus, drugs that disrupt fungal cell or protein function may also disrupt human cell or protein function.
D) Fungi are able to mutate more quickly than bacteria, so they quickly develop resistance to antifungal drugs.

Question 5

What is the major distinguishing characteristic of fungi?

A) acquiring nutrition through ingestion
B) sedentary lifestyle
C) prokaryotic cells
D) nutrient acquisition via external digestion
E) decomposition of dead organisms

Question 6

Chemicals, secreted by soil fungi, which inhibit the growth of bacteria, are known as ________.

A) antibodies
B) aflatoxins
C) hallucinogens
D) antigens
E) antibiotics

Question 7

Which of the following is an important role for fungi in the carbon cycle?

A) Fungi release fixed carbon back to the environment for other plants and photosynthetic organisms to utilize.
B) Fungi provide fixed carbon to plants for the production of plant cellular tissues.
C) Fungi fix carbon by undergoing photosynthesis.
D) Fungi reduce atmospheric carbon dioxide.

Question 8

You are a forester charged with increasing productivity in a South American forest newly planted with pines from Oregon. You believe that the southern forest lacks the fungal diversity needed by the North American pines and that this lack of fungi is affecting the pines' productivity, but you have no evidence to support your ideas. To count how many fungal species were present in the Oregon forest, which methodology would you choose?

A) Count all the plant species and multiply by 6, as David Hawksworth did when determining the ratio of fungal to plant species in England.
B) Collect all the fruiting structures (mushrooms, morels, etc.) found aboveground.
C) Do direct sequencing on representative soil samples from across the forest.
D) Expose the trees to radiolabeled carbon dioxide and then collect the soil samples with the greatest radioactivity and do direct sequencing.

Question 9

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) meiosis
B) fertilization
C) karyogamy
D) plasmogamy
E) germination

Question 10

Which of these fungal features supports the phylogenetic conclusion that fungi are more closely related to animals than to plants?

A) Fungi are able to change their body shape continuously throughout their life.
B) Zygomycetes have flagellated gametes.
C) Fungi store polysaccharides as starch.
D) The cell walls of fungi are made of chitin.

Question 11

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, whereas 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 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

Question 13

The vegetative (nutritionally active) bodies of most fungi are ________.
I) composed of hyphae
II) referred to as a mycelium
III) usually underground

A) I and II
B) II and III
C) only II
D) I and III
E) I, II, and III

Question 14

Among the organisms listed here, which are thought to be the closest relatives of fungi?

A) animals
B) vascular plants
C) mosses
D) brown algae
E) slime molds

Question 15

Fungi with hyphae ________.

A) acquire their nutrients by phagocytosis
B) have a body plan that is a unicellular sphere
C) have cell walls that consist mainly of cellulose microfibrils
D) are adapted for rapid directional growth to new food sources
E) reproduce asexually by a process known as budding

Question 16

Predict what you would see if you were looking at a new species of Zygomycetes.

A) a zygote enclosed in a tough outer coat
B) flagellated spores
C) susceptibility to fungicide
D) multicellularity
E) its ability to form an association with plant roots

Question 17

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

A) fungal haustoria
B) soredia
C) fungal enzymes
D) increased oxygen levels
E) larger bacterial populations

Question 18

All fungi are ________.

A) symbiotic
B) heterotrophic
C) flagellated
D) pathogenic
E) decomposers

Question 19

The question(s) below refer to the following phylogenetic trees.
Which tree depicts the microsporidians as a sister group of the ascomycetes?

A) I
B) II
C) III
D) IV

Question 20

Fungi that absorb nutrients from decaying plant matter are called ________.

A) saprobes
B) mycorrhizae
C) mushrooms
D) yeasts
E) molds

Question 21

Use the following information to answer the question(s) below.
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 4 to 5 days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100 percent; 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 pseudopods
E) by hyphae

Question 22

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 potentially even dikaryotic cells
E) is strong support for the claim that fungi are not truly eukaryotic

Question 23

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

A) This plant grows best when AMF taxa A or C are 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 24

Use the following information to answer the question(s) below.
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 4 to 5 days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100 percent; other species seem able to survive the infection.
Why are mycorrhizal fungi superior to plants at acquiring mineral nutrition from the soil?

A) Hyphae are 100 to 1000 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 25

Why does total biomass (graph e in the accompanying figure) 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 26

The sporangia of the bread mold Rhizopus are ________.

A) asexual structures that produce haploid spores
B) asexual structures that produce diploid spores
C) sexual structures that produce haploid spores
D) sexual structures that produce diploid spores

Question 27

Use the following information to answer the question(s) below.
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 below, 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 in the accompanying 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 fungus A is present
C) AMF fungus B is present
D) AMF fungus C is present
E) all AMF are present

Question 28

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 29

In septate fungi, what structures allow cytoplasmic streaming to distribute needed nutrients, synthesized compounds, and organelles throughout the hyphae?

A) multiple chitinous layers in cross-walls
B) pores in septa
C) complex microtubular cytoskeletons
D) two nuclei
E) tight junctions that form in cross-walls between cells

Question 30

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
E) Microsporidia

Question 31

Which of the following characteristics is unique to chytrids compared to other groups of fungi?

A) flagellated spores
B) endospores
C) autotrophic mode of nutrition
D) cell walls of cellulose
E) nucleotide sequences of several genes

Question 32

What group of fungi has the ability to penetrate its host's cell wall, thus increasing the efficiency with which materials are passed from fungus to host?

A) ectomycorrhizal fungi
B) arbuscular mycorrhizal fungi
C) endophytes
D) lichens

Question 33

Which of the following terms refers to symbiotic relationships involving fungi living between the cells in plant leaves?

A) pathogens
B) endosymbioses
C) endophytes
D) lichens
E) mycorrhizae

Question 34

Use the following information to answer the question(s) below.
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 4 to 5 days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100 percent; other species seem able to survive the infection.
It has been hypothesized that fungi and plants have a mutualistic relationship because fungi provide critical nitrogen for the plants' use. How do we know this happens? In experiments using radioactively labeled ________.

A) nitrogen, plants acquired more radioactive nitrogen when they were associated with fungi
B) nitrogen, labeled nitrogen showed up in fungi when the fungi were symbiotic with plants
C) nitrogen, when plants were associated with fungi, the plants could fix labeled nitrogen
D) proteins, plants transported labeled proteins to adjacent fungi

Question 35

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?

A) parasitic
B) mutualistic
C) commensal
D) predatory

Question 36

Use the following information to answer the question(s) below.
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 4 to 5 days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100 percent; other species seem able to survive the infection.
The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to ________.

A) the ability to form haustoria and parasitize other organisms
B) avoiding sexual reproduction until the environment changes
C) the potential to inhabit almost all terrestrial habitats
D) the increased probability of contact between different mating types
E) an extensive surface area well suited for invasive growth and absorptive nutrition

Question 37

You are given an organism to identify. It has a fruiting body that contains many structures with eight haploid spores lined up in a row. What kind of a fungus is this?

A) zygomycete
B) ascomycete
C) deuteromycete
D) chytrid
E) basidiomycete

Question 38

Use the following information to answer the question(s) below.
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 below, 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 the graphs in the accompanying figure, which of the following plant species is most likely NOT to form mycorrhizal associations?

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

Question 39

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?

A) This is always the first group of fungi to begin any kind of plant decomposition.
B) This fungal group can break down the tough lignin, which cannot be harnessed for energy, to get to the more useful cellulose.
C) This is the only group of fungi that can use lignin for adenosine triphosphate (ATP) production.
D) This enzyme releases heat energy from the breakdown of lignin that is used to kill off competing fungi.

Question 40

Why is it important that ectomycorrhizal fungi (EMF) have peptidase enzymes?

A) These enzymes are necessary to break through the tough lignin layers in plants.
B) These enzymes assist with the breakdown of cellulose.
C) These enzymes are needed to release nitrogen from dead plant material in colder environments.
D) These enzymes catalyze the formation of the compounds used during decomposition.

Question 41

In both lichens and mycorrhizae, what does the fungal partner provide to its photosynthetic partner?

A) carbohydrates
B) fixed nitrogen
C) antibiotics
D) water and minerals
E) protection from harmful ultraviolet light

Question 42

Some fungi have been instrumental in the development of human culture, including __________ in the Phylum ________ as they have been in use for hundreds of years in producing beer and bread.

A) chytrids; Chytridiomycota
B) yeasts; Ascomycota
C) puffballs; Basidiomycota
D) bread molds; Zygomycota
E) arbuscular mycorhizae; Glomeromycota

Question 43

Microsporidians are considered parasitic because of the ability to penetrate their host cells using ________.

A) a mycelium
B) a polar tube
C) sporangia
D) chitin

Question 44

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

A) Fungal cells are enclosed within algal cells.
B) Lichen cells are enclosed within fungal cells.
C) Photosynthetic cells are surrounded by fungal hyphae.
D) The fungi grow on rocks and trees and are covered by algae.
E) Algal cells and fungal cells mix together without any apparent structure.

Question 45

________ form ectomycorrhizal relationships with temperate forest trees while ________ form arbuscular (endomycorrhizal) relationships with plants in grasslands and tropical forests.

A) Zygomycetes; chytridiomycetes
B) Ascomycetes; zygomycetes
C) Basidiomycetes; glomeromycetes
D) Glomeromycetes; ascomycetes
E) Chytridiomycetes; basidiomycetes

Question 46

Many amphibian populations have been decimated by a parasitic fungus classified as a member of the ________.

A) Chytridiomycota
B) Ascomycota
C) Basidiomycota
D) Zygomycota
E) Glomeromycota

Question 47

Lichens are symbiotic associations of fungi and ________.

A) mosses or algae
B) cyanobacteria or algae
C) green algae or liverworts
D) mosses or cyanobacteria
E) mosses or sponges