Chapter 31

Which of the following is a difference between plants and fungi?

Fungi are heterotrophic, and plants are autotrophic.
Plants have diploid and haploid phases, and fungi have only haploid stages.
Plants produce spores.
Fungi have cell walls.
Fungi are strictly asexual, and plants undergo sexual reproduction.

Fungi are heterotrophic, and plants are autotrophic. Fungi are heterotrophic and absorb their nutrients, and plants are photosynthetic.

Fungi obtain nutrients through _____.

absorption
ingestion
photosynthesis
endocytosis
chemosynthesis

absorption Fungi are heterotrophs that acquire their nutrients by absorbing small molecules from the surrounding medium.

The body of most fungi consists of threadlike _____, which form a network called a _____.

mycelia … dikaryon
sporangia … dikaryon
hyphae … chytrid
hyphae … mycelium
mycelia … hypha

hyphae … mycelium Hyphae form a network called a mycelium.

Which of the following is a characteristic of hyphate fungi (fungi featuring hyphae)?

They acquire their nutrients by phagocytosis.
Their cell walls consist mainly of cellulose microfibrils.
They reproduce asexually by a process known as budding.
Their body plan is a unicellular sphere.
They are adapted for rapid directional growth to new food sources.

They are adapted for rapid directional growth to new food sources.

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?

flagella-central vacuoles
tight junctions-plastids
desmosomes-tonoplasts
centrioles-plastids
gap junctions-plasmodesmata

gap junctions-plasmodesmata

What do fungi and arthropods have in common?

The haploid state is dominant in both groups.
Both groups are commonly coenocytic.
Both groups are predominantly heterotrophs that ingest their food.
The protective coats of both groups are made of chitin.
Both groups have cell walls.

The protective coats of both groups are made of chitin.

The vegetative (nutritionally active) bodies of most fungi are

usually underground.
composed of hyphae.
referred to as a mycelium.
All of these responses are correct.

All of these responses are correct.

Which tree depicts the closest relationship between zygomycetes and chytrids?

I
II
III
IV

III Sister taxa

Immediately after karyogamy occurs, which term applies?

diploid
heterokaryotic
plasmogamy
dikaryotic

diploid

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

means that sexual reproduction can occur in specialized structures.
results in heterokaryotic or dikaryotic cells.
is strong support for the claim that fungi are not truly eukaryotic.
results in multiple diploid nuclei per cell.
allows fungi to reproduce asexually most of the time.

results in heterokaryotic or dikaryotic cells.

If all of their nuclei are equally active transcriptionally, then the cells of dikaryotic fungi, in terms of the gene products they can make, are essentially

diploid.
alloploid.
haploid.
completely homozygous.
completely hemizygous.

diploid.

Which process occurs in fungi and has the opposite effect on a cell’s chromosome number than does meiosis I?

crossing over
plasmogamy
karyogamy
binary fission
mitosis

plasmogamy

Please refer to the following information to answer the question.

Diploid nuclei of the ascomycete, Neurospora crassa, contain 14 chromosomes. A single diploid cell in an ascus will undergo one round of meiosis, followed in each of the daughter cells by one round of mitosis, producing a total of eight ascospores.

What is the ploidy of a single mature ascospore?

haploid
triploid
polyploid
tetraploid
diploid

haploid

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 four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100%; other species seem able to survive the infection.

What makes it risky to rely on the presence of chitin in adult amphibian skin as the sole positive test for the presence of chytrids?

Other mycoses may be in progress in the same amphibian simultaneously.
Bacterial infections may be simultaneously underway in the amphibian.
The amphibian may harbor arthropod ectoparasites simultaneously.
Three of the responses above are correct.
Two of the responses above are correct.

Two of the responses above are correct.

An important example of interaction between fungi and certain other organisms is mycorrhizae, in which the fungal partners _____.

help plants take up nutrients and water
control soil nematodes
cause the decay of cellulose and lignin
provide carbohydrates to the plant partner
sicken herbivores that attempt to feed on plants

help plants take up nutrients and water Mycorrhizae are mutualistic associations with the roots of plants, which enhance the absorption of nutrients.

The multicellular condition of animals and fungi seems to have arisen

by natural means, and is a homology.
by serial endosymbioses.
by convergent evolution.
due to common ancestry.
by inheritance of acquired traits.

by convergent evolution.

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 four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100%; other species seem able to survive the infection.

If infection primarily involves the outermost layers of adult amphibian skin, and if the chytrids use the skin as their sole source of nutrition, then which term best applies to the chytrids?
anaerobic chemoautotroph
anaerobic chemoheterotroph
aerobic chemoheterotroph
aerobic chemoautotroph

aerobic chemoheterotroph

Almost all of the members of this phylum form arbuscular mycorrhizae in a mutualistic partnership with plants.

Basidiomycota
Chytridiomycota
Zygomycota
Glomeromycota
Ascomycota

Glomeromycota Nearly all glomeromycetes form arbuscular mycorrhizae.

Fungi of the phylum Ascomycota are recognized on the basis of their production of _____ during sexual reproduction.

yeasts
lichens
saclike structures
a dikaryotic structure
flagellated zoospores

saclike structures The production of saclike structures during sexual reproduction is characteristic of the phylum Ascomycota.

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

heterotrophic mode of nutrition
cell walls of cellulose
presence of flagella
autotrophic mode of nutrition
nucleotide sequences of several genes

presence of flagella

What are the sporangia of the bread mold Rhizopus?

sexual structures that produce haploid spores
asexual structures that produce diploid spores
asexual structures that produce haploid spores
sexual structures that produce diploid spores

asexual structures that produce haploid spores

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?

alternation of generations
karyogamy
mycelial flagella
breezes distributing spores
cytoplasmic streaming in hyphae

cytoplasmic streaming in hyphae

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 four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100%; other species seem able to survive the infection.

Which of the following are protists, the organisms thought to share the closest ancestor with the chytrids?

diplomonads
choanoflagellates
nucleariids
algae
zygomycetes

nucleariids

Lichens are symbiotic associations of fungi and

A. mosses.
B. cyanobacteria.
C. green algae.
A and B
B and C.

B and C

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

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

Photosynthetic cells are surrounded by fungal hyphae.

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

fungicide might also kill mycorrhizae.
fungicide might also kill the native yeasts residing on the surfaces of the grapes.
sheeting is transparent so that photosynthesis can continue.
lichens growing on the vines’ branches are not harmed.

fungicide might also kill mycorrhizae

All fungi share which of the following characteristics?

heterotrophic
symbiotic
pathogenic
flagellated
act as decomposers

heterotrophic

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

flagellated spores
coenocytic hyphae
formation of resistant zygosporangia
the absence of chitin within the cell wall
parasitic lifestyle

flagellated spores

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

vascular plants
brown algae
slime molds
animals
mosses

animals

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

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

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

In fungi, haploid hyphae fuse to produce dikaryotic and then diploid nuclei, only to restore the haploid condition by meiosis before the growth of new hyphae. What is the significance of a transient diploid state in fungi?

The diploid state is more advanced than the haploid state.
All organisms must reproduce sexually at some point in their life cycle.
These sexual processes generate genetic variation.

These sexual processes generate genetic variation. The sexual processes of karyogamy and meiosis generate extensive genetic variation, a prerequisite for natural selection.