Question 1

All fungi are
A) symbiotic.
B) heterotrophic.
C) flagellated.
D) decomposers.

Accepted Answer

Fungi are heterotrophic, meaning they cannot manufacture their own food and must obtain their nutrients from organic substances.

Question 2

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.

Accepted Answer

The compounds probably provide a benefit to the fungi. Fungi produce compounds as a means of defense against their environment, including protecting themselves from other microorganisms. These compounds can also serve to attract pollinators or deter predators. Humans have found medicinal uses for some of these compounds due to their potential therapeutic properties. However, the primary function of the compounds is to benefit the fungi themselves.

Question 3

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

Accepted Answer

Soredia are structures that contain both fungal and algal cells, which can help establish lichens on the island. Lichens contribute to soil formation by breaking down rocks and accumulating organic matter, thus facilitating plant growth.

Question 4

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.

Accepted Answer

The fungal conversion from yeast to hyphal morphology allows such fast growth that the body's defenses are at least temporarily overwhelmed. The accumulation of pus in the lymph node and subsequent ulceration and drainage show that the immune system is not immediately successful in combating the infection.

Question 5

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

Accepted Answer

The answer of Fungi interact with many organisms in mutualistic...

Question 6

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

Accepted Answer

Since orchid seeds have miniscule cotyledons and virtually no endosperm, they lack the resources to grow on their own. Therefore, fungi that form a mutualistic relationship with the orchid can provide organic nutrients that the orchid seeds need in order to germinate and grow. These fungi absorb nutrients from their environment and can provide these nutrients to the orchid seeds in exchange for carbohydrates produced by the orchids through photosynthesis.

Question 7

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.

Accepted Answer

Truffles are detected by mammals, which suggests that they produce an odor or scent that is attractive to these animals. This scent likely helps guide the mammals to the truffle, and in turn, allows for spore dispersal through the animal's feces.

Question 8

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

Accepted Answer

The appearance of haustoria from the fungal partner within the photosynthetic partner and the subsequent slow growth rate of the photosynthetic partner suggests that the partnership is not purely mutualistic. This is because the fungal partner is benefiting at the expense of the photosynthetic partner. Therefore, option B is the correct choice. The other options do not relate to the scenario described above.

Question 9

The closest relatives of fungi are thought to be the
A) animals.
B) vascular plants.
C) mosses.
D) slime molds.

Accepted Answer

Fungi and animals share a common ancestor and are both members of the Opisthokonta supergroup. While fungi and plants do share similarities such as cell walls and the ability to produce spores, they have different modes of nutrition and their closest shared ancestor is much more distant. Mosses and slime molds are not as closely related to fungi as animals are.

Question 10

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

Accepted Answer

Endophytes are fungi or bacteria that live inside plant tissues, commonly found in the leaf mesophyll, where they form symbiotic relationships with the plant.

Question 11

Which of the following cells or structures are associated with asexual reproduction in fungi?
A) ascospores
B) basidiospores
C) zygosporangia
D) conidiophores

Accepted Answer

Conidiophores are fungal structures associated with asexual reproduction, specifically the production of conidia (asexual spores). Ascospores and basidiospores are produced through sexual reproduction in fungi, while zygosporangia are associated with the formation of zygospores through sexual reproduction in zygomycetes.

Question 12

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.

Accepted Answer

The discovery of asci, which are structures associated with sexual reproduction, indicates that S. schenkii has a sexual stage. Therefore, it should be reclassified from deuteromycetes, which are fungi with no known sexual stage.

Question 13

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.

Accepted Answer

The filamentous nature of fungal mycelia provides an extensive surface area that is well suited for invasive growth and absorptive nutrition. The mycelium can easily penetrate and navigate through soil, decaying organic matter, and other substrates to acquire nutrients. This is the most important advantage of the filamentous nature of fungal mycelia, as it allows fungi to obtain nutrients more efficiently than other organisms.

Question 14

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.

Accepted Answer

Discovering the lignin-digesting enzymes of fungi and using them to produce a biofuel would be a practical and feasible way to use fungi to improve the environment. This would help reduce waste and provide a sustainable source of energy. Option B is not practical since the process of breaking down large rock expanses into agricultural lands using fungal enzymes would take a very long time. Option C is not efficient since it focuses on increasing decomposition rates, which may produce more greenhouse gases. Option D is not scientifically feasible as oxygen-absorbing enzymes do not exist in fungi.

Question 15

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.

Accepted Answer

Lichens are a mutualistic relationship between fungi and photosynthetic organisms, either algae or cyanobacteria. The photosynthetic cells are surrounded by fungal hyphae, forming a unique structure called a thallus. This thallus allows for the exchange of nutrients and protection from environmental stressors. The fungi provide a protective environment for the photosynthetic cells and supply them with necessary minerals, while the photosynthetic cells provide the fungi with sugars produced through photosynthesis.

Quiz 31: Fungi

All fungi are

Fungi produce many compounds that humans are able to use medically. How can you account for these compounds?

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?

Fungi interact with many organisms in mutualistic ways. Which of the following involves a fungus that is mutualistic with another organism?

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?

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 ________.

The closest relatives of fungi are thought to be the

Mycorrhizae are to the roots of vascular plants as endophytes are to the ________ of vascular plants.

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

The most important adaptive advantage associated with the filamentous nature of fungal mycelia is

If you wanted to use fungi to improve the environment, which of the following research goals would make the most sense?

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