Deck 31: Fungi

Question 1

There was a mass extinction of plants and animals at the end of the Permian period 250 million years ago.Which of the following would be a reasonable prediction for the fungal fossil record?

A)There should be a massive increase in mycorrhizal fossils during the extinction and few afterward.
B)There should be a massive increase in saprophytic fossils during the extinction,and then a massive decline shortly after the extinction was complete.
C)There should be a massive decrease in all fungal fossils just prior to the time that plant and animal species started to decline,and the number of these fossils should remain low throughout the extinction period.
D)There should be a slow increase in all fungal fossils during the time that plant and animal species declined,with their numbers staying relatively high afterward since there was little competition from other species.

Answer 1

B

Question 2

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?

A)Plants acquire more radioactive nitrogen when they are associated with fungi.
B)Radioactively labeled nitrogen shows up in fungi when they are symbiotic with plants.
C)When plants are associated with fungi,they can fix atmospheric nitrogen that has been tagged with a radioactive label.
D)Radioactively labeled sugars in plants eventually find their way to their symbiotic fungi.

Answer 2

A

Question 3

This 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

Answer 3

B

Question 4

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 5

Most coal was formed during the Carboniferous period.What is a reasonable hypothesis that explains this observation?

A)Plants from this period did not require fungal associations.
B)There were not many saprophytic fungi during this period.
C)There were not many mycorrhizal fungi during this period.
D)Coal was formed from an explosion of fungal species during this period.

Question 6

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 six,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 above ground.
C)Do direct sequencing on representative soil samples from across the forest.
D)Expose the trees to radiolabeled CO₂ and then collect the soil samples with the greatest radioactivity and do direct sequencing.

Question 7

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

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

Question 8

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 9

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 10

Long,branching fungal filaments are called _____.

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

Question 11

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 12

A cell has two haploid nuclei.This means it is _____.

A)yeast
B)a zygote
C)haploid
D)diploid
E)dikaryotic

Question 13

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?

A)Chytrids
B)Zygomycetes
C)Basidiomycota
D)Ascomycota
E)Microsporidia

Question 14

You decide to bake bread from scratch.Which of the following is required to make your dough rise?

A)Saccharomyces cerevisiae
B)a mycorrhizal fungus
C)a saprophytic fungus
D)a mutualistic fungus
E)a multicellular fungus

Question 15

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?

A)The larger surface area allows for more material to be 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 16

You want to run an experiment to determine if an organism is a fungus.You place the organism in a petri dish with a small piece of wood.Which of the following results would support your hypothesis that your unknown organism is indeed a fungus?

A)The presence of glucose in the dish.
B)The presence of lignin in the dish.
C)The presence of decomposing bacteria in the dish.
D)The presence of cellulose in the dish.
E)The presence of mold on the wood.

Question 17

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

A)Fungi help release fixed carbon back to the environment for other plants and photosynthetic organisms to utilize.
B)One of fungi's main roles is to provide already fixed carbon to plants that the plants then use for the production of cellular tissues.
C)Fungi get involved in the fixation of carbon by undergoing photosynthesis.
D)Fungi reduce atmospheric carbon dioxide.

Question 18

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 they are associated with.
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 label experiments show that plants pass crucial raw materials to the fungus for manufacturing sugars.

Question 19

Which of these fungal features supports the phylogenetic conclusion that fungi are more closely related to animals than 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 20

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 ATP production.
D)This enzyme releases heat energy from the breakdown of lignin that is used to kill off competing fungi.

Question 21

Use the following information when answering the corresponding question(s).
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).Figure 31.2 illustrates the team's experimental setup.Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years;two of the three species formed ectomycorrhizae (Douglas fir,birch)and the other (cedar)formed arbuscular mycorrhizae.For the experiment,the researchers placed airtight bags over the Douglas fir and birch seedlings;into each bag,they injected either carbon dioxide made from carbon-13 or carbon-14 (¹³CO₂ and ¹⁴CO₂,isotopes of carbon).As the seedlings photosynthesized,the radioactive carbon dioxide was converted into radioactively labeled sugars that could be tracked and measured by the researchers.
Figure 31.2

Figure 31.3

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 forms arbuscular mycorrhizae

Question 22

Figure 31.5
Use the graphs in Figures 31.4 and 31.5 and the following information when answering the corresponding questions.
Canadian and Swiss researchers (van der Heijden et al. ,1998),interested in factors affecting biodiversity,grew a variety of grassland plants in combination with one of four arbuscular mycorrhizal (AMF)species,no AMF,or all four AMF species together;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 were present.Use the graphs in Figure 31.5 to answer the questions that follow.Note that 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.


Figure 31.4 Figure 31.5
Based on graphs (e)and (f)in Figure 31.5,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

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 24

Which fungal class is not matched with its most common habitat?

A)EMF → northern coniferous forests
B)EMF → warm climate forests
C)AMF → tropics
D)AMF → grasslands

Question 25

The fungus used to produce penicillin and other antibiotics belongs to which fungal lineage?

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

Question 26

Use the following information when answering the corresponding question(s).
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).Figure 31.2 illustrates the team's experimental setup.Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years;two of the three species formed ectomycorrhizae (Douglas fir,birch)and the other (cedar)formed arbuscular mycorrhizae.For the experiment,the researchers placed airtight bags over the Douglas fir and birch seedlings;into each bag,they injected either carbon dioxide made from carbon-13 or carbon-14 (¹³CO₂ and ¹⁴CO₂,isotopes of carbon).As the seedlings photosynthesized,the radioactive carbon dioxide was converted into radioactively labeled sugars that could be tracked and measured by the researchers.
Figure 31.2

Figure 31.3

Referring to Simard et al.(1997),what is the result that would most strongly refute their hypothesis?

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 27

Figure 31.5
Use the graphs in Figures 31.4 and 31.5 and the following information when answering the corresponding questions.
Canadian and Swiss researchers (van der Heijden et al. ,1998),interested in factors affecting biodiversity,grew a variety of grassland plants in combination with one of four arbuscular mycorrhizal (AMF)species,no AMF,or all four AMF species together;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 were present.Use the graphs in Figure 31.5 to answer the questions that follow.Note that 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.


Figure 31.4 Figure 31.5
Why does total biomass (graph e Figure 31.5)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 is the dominant plant species.
D)Lotus corniculatus is a rare species.

Question 28

Use the following information when answering the corresponding question(s).
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).Figure 31.2 illustrates the team's experimental setup.Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years;two of the three species formed ectomycorrhizae (Douglas fir,birch)and the other (cedar)formed arbuscular mycorrhizae.For the experiment,the researchers placed airtight bags over the Douglas fir and birch seedlings;into each bag,they injected either carbon dioxide made from carbon-13 or carbon-14 (¹³CO₂ and ¹⁴CO₂,isotopes of carbon).As the seedlings photosynthesized,the radioactive carbon dioxide was converted into radioactively labeled sugars that could be tracked and measured by the researchers.
Figure 31.2

Figure 31.3

Refer to Figure 31.2.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 29

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

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

Question 30

Figure 31.4
Use the following information when answering the corresponding question(s).
There is much discussion in the media about protecting biodiversity,but does it 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,no AMF,or all four AMF species together;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.Use the graphs in Figure 31.4 to answer the questions that follow.Note that 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 graphs in Figure 31.4,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 31

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.

Question 32

Figure 31.5
Use the graphs in Figures 31.4 and 31.5 and the following information when answering the corresponding questions.
Canadian and Swiss researchers (van der Heijden et al. ,1998),interested in factors affecting biodiversity,grew a variety of grassland plants in combination with one of four arbuscular mycorrhizal (AMF)species,no AMF,or all four AMF species together;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 were present.Use the graphs in Figure 31.5 to answer the questions that follow.Note that 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.


Figure 31.4 Figure 31.5
What is the major difference between Bromus erectus (graph f)and the other plant species (graphs a-d)included in the study?

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

Question 33

Figure 31.4
Use the following information when answering the corresponding question(s).
There is much discussion in the media about protecting biodiversity,but does it 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,no AMF,or all four AMF species together;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.Use the graphs in Figure 31.4 to answer the questions that follow.Note that 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 Figure 31.4,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?

A)Its biomass is greatest when no AMF are present.
B)Its biomass is greatest when AM fungus A is present.
C)Its biomass is greatest when AM fungus B is present.
D)Its biomass is greatest when AM fungus C is present.
E)Its biomass is greatest when all AMF are present.

Question 34

Many amphibian populations have been decimated by a parasitic fungi belonging to which lineage?

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

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

Figure 31.4
Use the following information when answering the corresponding question(s).
There is much discussion in the media about protecting biodiversity,but does it 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,no AMF,or all four AMF species together;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.Use the graphs in Figure 31.4 to answer the questions that follow.Note that 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.

Which of the following best explains the data given in graph (b)of Figure 31.4 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 37

Use the following information when answering the corresponding question(s).
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).Figure 31.2 illustrates the team's experimental setup.Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years;two of the three species formed ectomycorrhizae (Douglas fir,birch)and the other (cedar)formed arbuscular mycorrhizae.For the experiment,the researchers placed airtight bags over the Douglas fir and birch seedlings;into each bag,they injected either carbon dioxide made from carbon-13 or carbon-14 (¹³CO₂ and ¹⁴CO₂,isotopes of carbon).As the seedlings photosynthesized,the radioactive carbon dioxide was converted into radioactively labeled sugars that could be tracked and measured by the researchers.
Figure 31.2

Figure 31.3

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?

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