Deck 34: Fungi: Structure, Function, and Diversity

Question 1

A researcher is looking at different petri dishes that contain the yeast C. albicans. In the first dish she evaluates, she notices that the yeast do not form hyphae. Is this a mutant strain of yeast?

A)Yes, because the lack of hyphae denotes pathogenic yeast.
B)Yes, because yeast typically form hyphae.
C)No, because yeast do not normally form hyphae.
D)No, because yeast always form rhizoids and not hyphae.

Answer 1

C

Question 2

What is the specific role of cyanobacteria (or green algae) in lichens?

A)to help attach the lichens to surfaces
B)to synthesize defensive compounds
C)to provide fungi with carbohydrates produced by photosynthesis
D)to transport water throughout lichens
E)Cyanobacteria and green algae play no role in lichens, because lichens consist of fungi.

Answer 2

C

Question 3

What is the primary reason that fungi are important in the carbon cycle?

A)Fungi are able to reach incredibly large sizes, storing carbon while they are alive, and contributing carbon back to the atmosphere when they die and decompose.
B)Fungi are able to reach incredibly large sizes. Their high ratio of surface area to volume allows them to decompose large amounts of dead/decaying material, thereby returning carbon to the atmosphere.
C)Fungi are able to reach incredibly large sizes. They have a high ratio of surface area to volume and are able to fix more carbon through photosynthesis than other plants of comparable size.
D)Fungi are able to reach incredibly large sizes. Their high ratio of surface area to volume allows them to store more carbon (in the form of sugar)obtained through mycorrhizal associations than their symbiotic hosts.

Answer 3

B

Question 4

Many antibiotics work by inhibiting the synthesis of peptidoglycan, a component of the bacterial cell wall. What is a possible mechanism of action for anti-fungal drugs?

A)inhibiting the synthesis of peptidoglycan in fungi
B)inhibiting the synthesis of cellulose in fungi
C)inhibiting the synthesis of chitin in fungi
D)inhibiting the synthesis of lignin in fungi

Question 5

In some of the earliest plant fossils, there is evidence of mycorrhizal associations. Fungi may have been instrumental in plant colonization of land by:

A)colonizing areas as lichens and facilitating dispersal by terrestrial plants.
B)increasing nutrient uptake by early plant species.
C)increasing levels of organic matter in the soil.
D)releasing antibiotics to kill bacteria in the soil where plants would colonize.

Question 6

How do the two species that make up a lichen benefit from their symbiotic association?

A)The fungi receive carbohydrates from the algae, while the algae receive nitrogen from the fungi.
B)Both partners are able to grow on substrates on which each would not be able to grow on their own.
C)The algae receive carbon as a result of the fungi's ability to degrade lignin and cellulose, while the fungi receive nitrogen from the algae.
D)The fungi receive carbohydrates and, in some cases nitrogen, from the algae, while the algae gain a "home" that anchors them on the substrate.

Question 7

How do fungi digest their food sources?

A)by engulfing food particles and digesting them in vacuoles
B)by extending hyphae into a food source (e.g., an animal carcass)
C)by secreting enzymes externally, directly into their surrounding environment
D)by funneling food particles through septa, which break down larger molecules

Question 8

Imagine that you are on a nature walk. Your guide points out a lichen growing on a tree trunk and comments that lichens are actually a type of fungi. You know that this description is not correct. Why?

A)Lichens are actually vascular plants that produce hyphae instead of roots.
B)Lichens are actually composed of both fungi and green algae (or cyanobacteria).
C)Lichens are actually composed of both fungi and bryophytes.
D)Lichens are actually bryophytes that produce hyphae instead of roots.

Question 9

How does the size of fungal hyphae contribute to their ability to decompose detritus?

A)Fungal hyphae have a low ratio of surface area to volume, so they are able to absorb more nutrients.
B)Fungal hyphae have high ratio of surface area to volume, so they are able to absorb more nutrients.
C)Fungal hyphae have a low ratio of surface area to volume, so they are able to secrete more digestive enzymes into the surrounding environment to break down detritus.
D)Fungal hyphae have a high ratio of surface area to volume, so they are able to secrete enzymes into a greater area of soil to break down detritus.

Question 10

Consider the figure below. The bars show changes in primary productivity with and without endomychorrhizal associations for a group of plants that diverged early in the history of terrestrial plants. Which of the following statements supports the data shown in the figure?

A)Endomycorrhizal associations do not increase primary productivity in these plants.
B)Endomycorrhizal associations increase primary productivity in these plants.
C)Endomycorrhizal associations only help these plants at high CO₂ concentrations.
D)Endomycorrhizal associations only help these plants at low CO₂ concentrations.

Question 11

A gardener applies a specific fungicide to her plot that kills all mycorrhizal fungi. Which of the graphs below depicts changes in the amount of phosphorus in the soil after application of the fungicide?

A)graph A
B)graph B
C)graph C

Question 12

Which plant-fungal symbionts exchange nutrients with their host plant MOST efficiently?

A)ectomycorrhizal symbionts
B)endomycorrhizal symbionts
C)endophytic symbionts

Question 13

Yeasts are unicellular fungi that do not produce hyphae. However, they are descended from a common ancestor that did produce hyphae. Which of the following statements explains why yeasts do not produce hyphae?

A)Hyphae require many cells, so a unicellular organism is unable to produce hyphae.
B)Yeasts grow in nutrient-rich environments, so they do not require hyphal growth to reach regions high in nutrients.
C)Yeasts are descended from unicellular bacteria, and hyphal growth is not a characteristic of bacteria.
D)Yeasts are representative of the earliest fungal lineages before hyphal growth evolved in the group.

Question 14

Saprophytic (something that lives on dead and decaying material) fungi are essential to life on Earth because they:

A)grow in mycorrhizal association with the roots of most plants, providing minerals to the plants.
B)speed the recycling of nutrients.
C)help to digest sap in phloem of dead and dying trees.
D)recycle organic compounds into inorganic compounds.
E)respire like plants taking in CO₂ and decrease greenhouse gasses.

Question 15

The majority of an individual fungus lives "in" its food source. What characteristics of the fungal growth form make this a necessity?

A)Fungi have a high ratio of surface area to volume and are highly susceptible to dessication.
B)Fungi have a low ratio of surface area to volume and are highly susceptible to dessication.
C)Fungi require the stimulus of "pushing" through the substrate to stimulate growth.
D)Fungi require more nutrients than other organisms, and large amounts of nutrients can only be acquired by living in a host.

Question 16

Why might endophytes be able to help protect trees from pathogens that infect their leaves?

A)Because fungal endophytes produce hyphae, they have a greater chance of encountering pathogens within the leaf.
B)Because fungal endophytes can degrade cellulose and lignin, they are able break down the cell walls of many plant pathogens.
C)Because fungal endophytes disperse spores through the air, they are able to spread to leaves even at the tops of tall trees.
D)Because fungal endophytes have a shorter generation time than trees, they can more rapidly evolve new defenses.
E)Because fungal endophytes have cell walls containing chitin, they are able to present a larger diversity of receptor molecules on their surface that can detect pathogens.

Question 17

Many people can get an infection called ringworm, which isn't a worm but a fungus. The characteristic growth pattern is a circle on the infected portion of the skin. The edges of the circle tend to appear redder, or more irritated, than the center. Where did the infection begin?

A)It began at the margins of the circle where it is most irritated, and the fungus grew around the margin of the circle.
B)It began at the center of the circle, and the fungus grew out from the initial point of infection.
C)Multiple fungal spores landed in the shape of the circle and led to infection.

Question 18

If all of the fungi on Earth ceased to exist, what would happen to the local carbon cycle?

A)Because fungi are photosynthetic, less CO₂ would be removed from the atmosphere.
B)Because fungi are decomposers, less CO₂ would be released back into the atmosphere.
C)Because fungi are photosynthetic, more CO₂ would be removed from the atmosphere.
D)Because fungi are decomposers, more CO₂ would be released back into the atmosphere.

Question 19

How do fungi in the soil of rain forests encourage plant diversity?

A)By serving as pathogens for particular plant species, fungi favor the establishment of less-common plant species.
B)By serving as pollinators, fungi introduce plant diversity into new regions.
C)By forming mycorrizhae with plants, fungi introduce plant diversity into new regions.

Question 20

Recall that the phloem sap of vascular plants moves through the phloem as a result of turgor pressure. How are nutrients transported through fungi?

A)through hyphae, as a result of turgor pressure
B)through sieve tubes, as a result of turgor pressure
C)through vessel elements, as a result of turgor pressure
D)through hyphae, as a result of capillary action
E)through sieve tubes, as a result of capillary action

Question 21

The filaments that MOST fungi produce to absorb nutrients are called:

A)root hairs.
B)ectomycorrhizae.
C)hyphae.
D)chitins.
E)fruiting bodies.

Question 22

Which of the following BEST describes the role of fungi in an ecosystem?

A)decomposers
B)autotrophs
C)herbivores
D)carnivores
E)producers

Question 23

Fungi include:

A)yeasts.
B)decomposers.
C)pathogens.
D)smuts.
E)All of these choices are correct.

Question 24

Imagine that fungal hyphae were as thick as a human hair. How might this increase in thickness affect the ecological role of fungi?

A)Their rates of decomposition of detritus would decrease because their ratio of surface area to volume would be decreased.
B)Their rates of decomposition of detritus would increase because their ratio of surface area to volume would be increased.
C)There would be no effect on the rates of decomposition of detritus.
D)There would be no effect on the rates of decomposition of detritus because the fungi would still be heterotrophic.

Question 25

The network of branching filaments that form the main body of a multicellular fungus is the:

A)mycelium.
B)hypha.
C)fruiting body.
D)spore.
E)rhizoid.

Question 26

Which of the following statements MOST accurately describes the anatomy of a multicellular fungus?

A)Numerous hyphae make up a mycelium.
B)Numerous mycelia make up a hypha.
C)Numerous mycelia make up a fruiting body.
D)Numerous fruiting bodies make up a mycelium.
E)Numerous septa make up a hypha.

Question 27

The fungi are most closely related to:

A)haploid protists, which are organisms that also have haploid nuclei.
B)arthropods, which are organisms that also produce chitin.
C)plants, which are organisms that also grow in the ground.

Question 28

Which of the following statements comparing fungal and animal nutrition is CORRECT?

A)Fungi digest and then absorb food, whereas animals ingest and then digest food.
B)Fungi are autotrophs, whereas animals are heterotrophs.
C)Fungi and animals both ingest their food before digestion.
D)Fungi are unable to break down complex molecules, whereas animals can break down complex molecules.
E)Fungi and animals both actively move through the environment in search of food.

Question 29

The numerous thin filaments that make up the body of a multicellular fungus are the:

A)hyphae.
B)mycelia.
C)fruiting bodies.
D)spores.
E)rhizoids.

Question 30

A researcher has been studying lichens in his hometown. Since he began his study, he has noticed several lichens dying in the vicinity of a new factory. What is MOST likely causing the decrease in lichen populations?

A)the diversion of water sources to the factory (i.e., lichens are drying out)
B)an increase in air temperature, which is the result of CO₂ emissions from the factory
C)the blocking of sun by the factory (i.e., the lichens aren't getting enough sunlight)
D)an increase in industrial pollutants in the area

Question 31

The _____ is a web of hyphae produced by a fungus in response to encountering a food source.

Question 32

Lichens are able to obtain nutrients from their environment by:

A)secreting organic acids that liberate nutrients from surrounding materials.
B)associating with a specific photosynthetic symbiont.
C)digesting "pollutants" in highly polluted environments.
D)digesting small organisms that live on the surface of the lichen.

Question 33

Basidiomycetes are the only fungal group that produces lignin peroxidases, which are chemicals that can break down lignin and lignified tissues. Basidiomycetes growing within a fallen log would get less nutrition than ascomycetes because more of the cellulose in the log would be available to be broken down and absorbed.

Question 34

Which of the compounds found in wood are difficult to degrade (or break apart)?

A)cellulose
B)lignin
C)starch.
D)protein

Question 35

Fungi feed through extracellular digestion and then absorption. How would the rates of decomposition of detritus be altered if fungicide (something that kills fungi) were sprayed on the forest floor?

A)Decomposition rates would be lowered because fungi would be destroyed.
B)Decomposition rates would be higher because bacteria would take over the role of decomposition, and they reproduce at faster rates than fungi.
C)Decomposition rates would be the same because fungi don't have hyphae above ground, so they would not be destroyed.
D)Decomposition rates would be lowered because fungi would choose to grow in an area without fungicide.

Question 36

What is the advantage of a fungal body being composed of numerous thin hyphae instead of one or two very thick hyphae?

A)A greater surface area is available for absorption of nutrients.
B)Less energy is required to produce the hyphae.
C)Better support is provided by numerous hyphae.
D)More exposure to the sun allows for increased photosynthesis.
E)All of these choices are correct.

Question 37

Fungal cell walls are composed of what material?

A)chitin
B)cellulose
C)peptidoglycan
D)lignin
E)glycogen

Question 38

The development of septa in the hyphae of fungi was an important evolutionary step. Why?

A)If a hypha is damaged, fungi can seal septal pores to prevent the cytoplasm from leaking out.
B)If a hypha is damaged, septa can secrete chemicals to attract symbiotic cyanobacteria.
C)Septa can produce fungal spores during both sexual and asexual reproduction.
D)Septa can produce different fungal mating types that aid in sexual reproduction.

Question 39

Fungi can cause various diseases, but they can also be beneficial to humans. Which of the following result from fungi?

A)smut or rust crop infections
B)leavened bread
C)soy sauce
D)certain skin infections
E)some soft cheeses

Question 40

Which of the following materials can serve as food sources for fungi?

A)elephant dung in the Serengeti
B)leaf matter in a New England forest
C)a bear carcass in Siberia
D)a fallen redwood tree in California
E)the fruit in your refrigerator

Question 41

Which feature of fungi allows the production of large fruiting bodies?

A)the ability to produce hyphae
B)the ability to grow by means of mitotic cell division
C)turgor pressure in hyphae
D)the presence of flagellated sperm

Question 42

Which of the following is an example of a mutualistic association involving a fungus?

A)Fungal hyphae penetrate a plant root, then provide the plant with nutrients and receive organic molecules in return.
B)Fungal spores infect and then eventually kill an insect.
C)A fungus produces rings that allow it to capture and feed upon nematode worms.
D)A fungus invades the xylem of a tree and eventually kills it.
E)A fungus causes athlete's foot in a human.

Question 43

Which of the following statements about lichens is INCORRECT?

A)Lichens are symbiotic relationships between a fungus and a plant.
B)The partnership in a lichen is not species specific.
C)Lichens can reproduce asexually.
D)Lichens can extract nutrients from rocks or rainfall.
E)Lichens are very sensitive to air pollution.

Question 44

When plasmogamy occurs between two fungi of compatible mating types, a dikaryotic cell is formed in the hyphae. For some groups of fungi, only one or a few cells are dikaryotic. In other groups of fungi, a majority of the cells that make up the fungal hyphae are dikaryotic. What might be an advantage of having dikaryotic hyphae?

A)Dikaryotic hyphae have more nuclei and thus can achieve higher rates of transcription and translation, and make more digestive enzymes per cell.
B)Dikaryotic hyphae are able to divide more rapidly than hyphae with only one nucleus.
C)Karyogamy can occur in more than one cell and more fruiting bodies can be produced, increasing the number of spores produced during meiosis.
D)Karyogamy can occur more rapidly when a dikaryotic hypha encounters a compatible mating type.

Question 45

Which of the following statements about mycorrhizae is CORRECT?

A)Endomycorrhizal fungi constitute a monophyletic group.
B)The hyphae of ectomycorrhizal fungi penetrate plant root cells.
C)Endomycorrhizal fungi provide plant roots with nutrients, whereas ectomycorrhizal fungi do not.
D)Endomycorrhizal fungi receive carbohydrates from plants, whereas ectomycorrhizal fungi do not.
E)Endomycorrhizal fungi branch extensively in the soil surrounding plant roots, whereas ectomycorrhizal fungi do not.

Question 46

When a fungus encounters a particularly rich food source, what is the expected result?

A)Hyphae branch and extend rapidly from their tips to form a mycelium.
B)Hyphae stop growing in length, but increase in diameter.
C)Individual hyphae begin to produce spores.
D)Hyphae stop growing and a fruiting body forms to exploit the food source.
E)The mycelium breaks down into widely separated hyphae.

Question 47

During which of the following processes does the cytoplasm of two hyphal cells fuse to form a dikaryotic (n + n) cell?

A)karyogamy
B)heterokaryogamy
C)plasmodesmatogamy
D)plasmogamy

Question 48

Unicellular fungi are also known as:

A)yeasts.
B)bacteria.
C)buds.
D)hyphae.
E)mushrooms.

Question 49

Imagine that sexual reproduction could occur between hyphae that were the same mating type. How might this affect rates of evolution in fungi?

A)Rates of evolution would be lower because genetic variation would be lower.
B)Rates of evolution would be higher because more novel genetic combinations are generated through sexual reproduction.
C)Rates of evolution would stay the same because as long as sexual reproduction is occurring, it does not matter if it is between individuals of the same or different mating type.

Question 50

Fungi are the most important decomposers of wood in the ecosystem.

Question 51

Which of the following would be considered a fruiting body?

A)a portobello mushroom in the grocery store
B)a toadstool in your backyard
C)shiitake mushrooms growing on the trunk of a tree
D)a truffle growing underground

Question 52

Within the fungal body, nutrients are transported from the _____ to the _____ by the process of _____.

A)mycelium; fruiting body; bulk flow
B)fruiting body; mycelium; diffusion
C)mycelium; fruiting body; active transport
D)fruiting body; mycelium; vesicular transport
E)mycelium; fruiting body; diffusion

Question 53

A researcher isolates a species of fungus that only reproduces sexually. He introduces individual hyphae-all of the same mating type (e.g., with the same mating-type alleles)-into a petri dish. What do you expect will happen with the fungi in this dish?

A)Fungi in the dish will mate, forming spores by means of sexual reproduction.
B)Fungi in the dish will not mate, but will form spores by means of asexual reproduction.
C)No spores will be formed by fungi in the petri dish.

Question 54

Which of the following statements is TRUE regarding fungal spores?

A)They can be formed by means of asexual reproduction.
B)They can be formed by means of sexual reproduction.
C)They are often shaped to resist drag (similar to an airplane wing).
D)They are often shaped to promote drag (similar to a parachute).
E)They can be dispersed by fruiting bodies.

Question 55

Which of the following statements is true in parasexual fungi?

A)Crossing over occurs during mitosis.
B)Crossing over occurs during meiosis.
C)Chromosomes are lost until haploid (1n)cells are achieved.
D)Chromosomes are added until haploid (1n)cells are achieved.
E)The parasexual fungi produce dikaryotic (n + n)cells.

Question 56

Which of the following is NOT an example of a fungal pathogen?

A)endophytes
B)smuts
C)rusts
D)athlete's foot
E)vascular wilt fungus

Question 57

_____ is the process by which the nuclei within a heterokaryotic fungal cell fuse.

A)Karyogamy
B)Plasmogamy
C)Mitosis
D)Meiosis

Question 58

Which type of reproduction is typical in many molds and yeasts?

A)sexual reproduction through plasmogamy of diploid parental mycelia, and then production of spores
B)sexual reproduction through plasmogamy of haploid parental mycelia, and then production of spores
C)asexual reproduction of haploid spores from a diploid parental organism
D)asexual reproduction of haploid spores from a haploid parental organism

Question 59

How do endophytes differ from endomycorrhizal fungi?

A)Endophytes live within leaves, whereas endomycorrhizal fungi live within roots.
B)Endomycorrhizal fungi are beneficial to the plant, whereas endophytes are harmful.
C)Endophytes are unicellular, whereas endomycorrhizal fungi are multicellular.
D)Endophytes help plants absorb nutrients, whereas endomycorrhizal fungi help plants defend against predators and pathogens.
E)Endophytes penetrate into plant cells, whereas endomycorrhizal fungi live within and between plant cell walls.

Question 60

Spore production in fungi is an important part of reproduction. What is the adaptive significance of the protective coat found around fungal spores?

A)The protective coat inhibits spore growth until other fungi in the area die.
B)The protective coat keeps the spore viable until environmental conditions allow fungal growth.
C)The protective coat increases the distance of dispersal from the parental fungus.
D)The protective coat inhibits fungal growth wherever the spore lands.

Question 61

Mushrooms growing in your backyard are examples of _____, which are above-ground structures formed by fungi to disperse spores.

Question 62

The stage of the fungal life cycle during which two or more genetically distinct nuclei are found in the same cell is referred to as:

A)the heterokaryotic stage.
B)the diploid stage.
C)the zygote stage.
D)karyogamy.
E)plasmogamy.

Question 63

In a parasexual fungal species, genetic diversity would be the result of:

A)meiotic recombination.
B)mitotic recombination.
C)recombination between different mating-type alleles.
D)plasmogamy recombination.
E)hyphae recombination.

Question 64

Parasexuality is unique among eukaryotes. Parasexuality provides the benefits of sexual reproduction, without going through which of the following?

A)karyogamy
B)meiosis
C)plasmogamy
D)recombination

Question 65

Imagine that sexual reproduction could occur between hyphae that were the same mating type. How might this affect the population of one species of fungus?

A)The frequency of sexual reproduction would be higher.
B)The frequency of sexual reproduction would be lower.
C)The frequency of sexual reproduction would remain the same.

Question 66

How are asci and basidia similar?

A)Both are produced by glomeromycetes.
B)Both are produced by chytrids.
C)Both contain haploid (1n)spores.
D)Both are contained within haploid (1n)fruiting bodies.

Question 67

Which of the following statements is TRUE regarding fungi?

A)Many fungi demonstrate both asexual and sexual life cycles.
B)Fungi are heterotrophs.
C)Fungi are autotrophs.
D)Fungi only reproduce asexually (e.g., via budding).
E)Fungi are decomposers.

Question 68

In what ways are mycelia and fruiting bodies similar?

A)Both are composed of hyphae.
B)Both grow below ground.
C)Both produce spores.
D)Both are involved in gathering food.
E)All of these choices are correct.

Question 69

Which of the following statements about spores is NOT true?

A)Both sexual and asexual spores are produced by meiosis.
B)Both sexual and asexual spores allow for dispersal to new areas.
C)Asexual spores are genetically identical to the parent, whereas sexual spores are not.
D)Fungal species vary in their reliance on asexual versus sexual spore production.
E)Spore production is triggered, in part, by a shortage of resources.

Question 70

In fungi, _____ cells are cells composed of the cytoplasm of two or more cells, but they retain distinct sets of chromosomes contained in separate nuclei.

A)diploid
B)haploid
C)heterokaryotic
D)haplokaryotic

Question 71

All fungi can only reproduce sexually.

Question 72

Fungi are more likely to "self-fertilize" because hyphal strands of the same individual are in close proximity to each other.

Question 73

Why do fungi produce fruiting bodies?

A)to enhance spore dispersal
B)to provide food for animals
C)to enhance photosynthesis
D)to defend against predators
E)to indicate territorial boundaries

Question 74

One of the greatest advantages of sexual reproduction is the generation of variability.

Question 75

Which of the following fungal structures aid in spore dispersal?

A)fruiting bodies
B)septa
C)mycelia
D)pores
E)hyphae

Question 76

A scientist collects a spore from a new species of fungus and observes that this spore has a flagellum. What does the presence of a flagellum suggest about the lifestyle of this species?

A)It is aquatic.
B)It is an endomycorrhizal fungus.
C)It relies on insects for spore dispersal.
D)It is unicellular.
E)Its spores are produced asexually.

Question 77

Fungi are more likely to "self-fertilize" because hyphal strands of the same individual are in close proximity to each other.

Question 78

Below the surface of the soil, fungi can grow over a large area by extending their hyphae. Typically, when two hyphae are touching, mating can occur. How do fungi prohibit self-fertilization when the majority of hyphae in a localized area are likely from the same individual?

A)Fungi do not prohibit self-fertilization and readily self-fertilize.
B)Each fungal individual has specific alleles that allow it to identify fungal hyphae that are not the same mating type.
C)Fungal hyphae from the same individual can combine, but will use parasexuality to generate genetic diversity.
D)Fungal individuals of the same mating type must meet in order to mate.

Question 79

In the sexual life cycle of fungi, when is genetic variation generated?

A)during karyogamy when nuclei become diploid
B)during plasmogamy when hyphae become heterokaryotic
C)during germination when spores begin to grow
D)during meiosis when spores are formed

Question 80

When you eat a mushroom, what part of the fungus are you consuming?

A)a reproductive structure
B)a food-gathering structure
C)a photosynthetic structure
D)a support structure
E)a defensive structure