Deck 38: Fungi

Question 1

Organisms within the Kingdom Fungi are currently classified

A) phylogenetically.
B) on the basis of their reproduction, and are monophyletic.
C) on the basis of morphology, and are therefore a natural group.
D) into six groups.
E) by DNA analysis.

Answer 1

into six groups.

Question 2

Comparative molecular and biochemical analysis of fungi and protists suggest that fungi:

A) evolved from red algae.
B) evolved from the chytrid group of protists.
C) are distinct enough to be in a completely different evolutionary lineage to the other eukaryotes.
D) adopted a diploid nucleus in their vegetative cells.
E) and protists are closely related.

Answer 2

are distinct enough to be in a completely different evolutionary lineage to the other eukaryotes.

Question 3

What term best describes fungi that live in partnership with another fungi?

A) Parasite
B) Saprophyte
C) Mutualist
D) Mycelium
E) Symbiotic

Answer 3

Mutualist

Question 4

Hyphal growth is best described as

A) meristematic.
B) apical.
C) lateral.
D) branched.
E) mycelial.

Question 5

Fungal cell walls

A) differ from plant cell walls in that they lack polysaccharides.
B) are physiologically similar to plant cell walls, but not structurally similar.
C) are made of chitin only.
D) are similar to the plasma membrane and consist of lipids.
E) are synthesised in the Golgi apparatus.

Question 6

Some fungi have fruiting bodies composed of pseudoparenchyma tissue forming hyphal mats called

A) asci.
B) stroma.
C) rhizomorphs.
D) clerotia.
E) septa.

Question 7

Sclerotia in fungi are

A) meshed hyphae forming a fruiting body.
B) compacted hyphae forming a dormancy structure.
C) made up of pseudoparenchyma.
D) elaborate fruiting bodies.
E) spore-containing structures.

Question 8

A swelling at the tip of the hypha that can penetrate the host without damaging it is called

A) a conidiophore.
B) an haustorium.
C) an appressorium.
D) a rhizomorph.
E) the sclerotium.

Question 9

A hyphal cell contains two haploid nuclei that came from different sources. Such a cell would be described as

A) monokaryotic.
B) homokaryotic.
C) heterokaryotic.
D) plasmogamy.
E) karyogamic.

Question 10

Fungal mitosis is unusual because

A) the nuclear envelope remains intact except in the basidiomycetes.
B) at metaphase, the chromosomes align longitudinally rather than equatorially.
C) hyphae from compatible individuals anastomose.
D) microtubules do not connect to the kinetophores because the intact nuclear membrane precludes spindle formation.
E) plasmogamy delays karyogamy.

Question 11

Fungal nutrition is best described as

A) heterotrophic.
B) saprotrophic.
C) successional.
D) saprotrophic and parasitic.
E) degradative.

Question 12

Fungi exhibit successional stages in the decomposition of organic matter. In observing the decomposition of a complex substrate you would expect

A) the most competitive fungi to colonise the substrate first.
B) the most competitive fungi to be the fastest growing.
C) the first fungi to appear are usually Ascomycota which use cellulose and simple sugars.
D) the most primitive fungi, such as the Zygomycetes, in the pioneering stages and the most advanced fungi, such as the Basidiomycetes, in the latter stages of succession.
E) that the evolution of fungi is not correlated with competitive ability and succession.

Question 13

In nearly all fungi, the most common carbon source used is

A) glucose.
B) glycogen.
C) sucrose.
D) fructose.
E) glycerol.

Question 14

Fungi tolerate a wide range of environmental extremes. Which statement best describes a strategy that adapts fungi to an environmental extreme?

A) Xerotolerance is achieved through the interconversion of storage compounds, which makes water available.
B) Mesophiles adjust the lipid composition of their membranes to maintain constant membrane fluidity.
C) Hydrophobins are produced by fungi to enable them to grow in water.
D) Psychrophiles initiate dormancy at 5 $\degree$ C to prevent metabolic damage at low temperatures.
E) Halophiles rely on the rigidity of fungal cell walls to prevent turgor pressure from causing lysis.

Question 15

Which statement about fungal growth conditions is INCORRECT?

A) Fungi do not require light to grow.
B) Fungi that grow in very dry conditions can obtain water as a metabolic product of carbohydrate breakdown.
C) Cold or heat shock may be necessary in some species to stimulate spore formation.
D) Macrofungi have gravity-sensing mechanisms to enable them to orient their fruiting bodies.
E) Fungi are found in all environments except marine environments.

Question 16

Which statement about fungal spores is INCORRECT?

A) Sexual spores are always haploid.
B) Fungi reproduce by spores produced both sexually and asexually.
C) Spores have the ability to be dispersed over long distances.
D) There are eight ascospores in each ascus.
E) Spores produced under favourable conditions are generally asexually produced.

Question 17

Memnospores

A) are one of four types of conidiospores.
B) differ from xenospores in that they are produced in great numbers under favourable environmental conditions.
C) are sexual survival spores produced in response to nutrient depletion, the accumulation of staling products, or an environmental stimulus.
D) are minute, asexual animal parasites that lack mitochondria.
E) are produced more commonly than xenospores.

Question 18

Unlike the oomycetes, which are protists, chytrids ought to be classified with the fungi because

A) the pathway for lysine synthesis includes the intermediate diaminopimelic acid instead of aminoadipic acid.
B) they form motile zoospores.
C) some forms manifest a coenocytic mycelium.
D) their hyphae are coenocytic.
E) their mitochondria have flat, plate-like cristae.

Question 19

Phylum Zygomycota is a group of fungi that is characterised by

A) having a thick-walled structure surrounding a diploid zygote.
B) not having a known sexual stage.
C) being mutualistic symbionts with algae.
D) fusion of hyphae occurs in sexual reproduction.
E) having many plant-like characteristics.

Question 20

A particular fungus you are describing is a fast-growing saprophytic mould, where the hyphae lack any dividing septa and there are numerous microscopic sporangia. It is most likely to belong in the phylum

A) Zygomycota.
B) Ascomycota.
C) Basidiomycota.
D) Glomeromycota.
E) Deuteromycota.

Question 21

Yeasts used to ferment sugar to alcohol are

A) zygomycetes.
B) ascomycetes.
C) glomeromycota.
D) basidiomycetes.
E) deuteromycetes.

Question 22

Which of the following statements about basidiomycetes is true?

A) Basidiomycetes include important biotrophic plant pathogens, such as rusts, which manifest specialised structures, such as appressoria and haustoria, to overcome plant defences and exploit their hosts.
B) Basidiomycetes lack the dolipore septa of ascomycetes.
C) The vegetative mycelium of basidiomycetes is haploid and multinucleate and has septa with simple pores.
D) The life cycle of basidiomycetes differs from that of ascomycetes. While both groups have delayed karyogamy, the dikaryon is only found in the basidiocarp of basidiomycetes.
E) Basidiomycetes lack the clamp connections formed in mitotically dividing cells, which preserves the dikaryon observed in ascomycetes.

Question 23

In fungi, basidiospores are

A) haploid.
B) diploid.
C) the product of mitosis in the basidium.
D) found only in primary hyphae.
E) found only in secondary hyphae.

Question 24

In phylum Basidiomycota, the basidiospores form

A) from a monokaryotic basidium.
B) when two short hyphal branches fuse.
C) inside a thick-walled structure where two hyphae have fused.
D) in the primary mycelium.
E) on the basidiocarp

Question 25

The phylum Deuteromycota

A) is referred to as the fungi imperfecti because teleomorphs are commonly known in this group.
B) has members classified into natural groups on the basis of sexual and asexual spores.
C) is polyphyletic precluding a phylogenetic classification at this taxonomic rank.
D) includes large mushrooms, puffballs and bracket fungi.
E) is closely related to the phylum Ascomycota, to which all members of the group bear a strong morphological resemblance.

Question 26

The phylum Mycophycota

A) is an ecological rather than taxonomic grouping of fungi.
B) are classified on the conidiospore formation.
C) has members which reproduce by fragmentation or the production of sori.
D) is most closely related to the deuteromycetes.
E) form commensal relationships with cyanobacteria or chlorophytes.

Question 27

Mycorrhizae are mutualisms between fungi and plants. Which of the following statements about mycorrhizae is CORRECT?

A) Ectomycorrhizae form more intimate associations with the cells in plant roots than arbuscular mycorrhizae.
B) The Hartig net of mycelium is characteristic of the ectomycorrhizae.
C) Orchid mycorrhizal associations are most likely to be facultative particularly for the orchid.
D) Mycorrhizal fungi increase the uptake of carbon by the associated plant.
E) Epacrid mycorrhizae facilitate the growth of temperate forest trees, such as eucalypts and pines, in nutrient-depleted forest soils.

Question 28

Mycorrhizae are important because they assist plants to

A) resist temperature extremes.
B) take up mineral nutrients.
C) grow in acid soils.
D) increase phosphorous uptake in phosphate-deficient soils.
E) All of the answers are correct.

Question 29

What feature of fungi is most attractive to biotechnologists?

A) Their high nutrient value.
B) They are easy to grow in the laboratory.
C) They naturally secrete enzymes.
D) They taste great.
E) They have a simple genome.

Question 30

The kingdom Fungi is believed to have evolved from

A) euglenoids.
B) choanoflagellates.
C) green algae.
D) mycetozoa.
E) kinetoplastids.

Question 31

Which of the following statements about Fungi is CORRECT?

A) Many Zygomycota have lost their sexual stage and reproduce only asexually.
B) The earliest groups of Fungi are the Dikarya.
C) The Microsporidia, which includes mushrooms, evolved regular septa in their hyphae.
D) Morphological similarities between Fungi and red algae demonstrate convergent evolution towards the fungus.
E) Primitive Fungi adopted a diploid rather than a haploid nuclei in their vegetative cells and evolved a unique form of mitosis.

Question 32

Fungi grow and explore their substrates

A) production of coenocytic hyphae from rhizoids.
B) cell division by formation of septa across the hyphae.
C) increasing the hyphae length by absorption of nutrients through the cell wall.
D) by extension from the hyphal tip.
E) production and release of spores from the sporangium.

Question 33

Septa

A) form regular cross-walls formed during cell division of fungi.
B) grow inwards from the cell wall.
C) have a hole in them to allow cytoplasmic continuity along the hyphae.
D) form continuous walls only to separate spores.
E) All of the answers are correct.

Question 34

Sclerotia are

A) sites of new cell wall deposition.
B) a dormant stage of fungi which is resistant to degradation.
C) spores produced on elaborate fruiting bodies.
D) a mat of hyphae involved in spore production.
E) hyphae strands covered by a tough outer sheath.

Question 35

Dikarya differ from Zymomycota in that the dikarya

A) have multinucleate cells.
B) undergo asexual reproduction.
C) produce spores in elaborate fruiting bodies.
D) separate new cells and their nuclei with septa.
E) have coenocytic hyphae.

Question 36

Genetic diversity in asexual fungi is generated by

A) random mutation.
B) regular grafting of hyphae to enable recombination.
C) DNA methylation to change gene expression.
D) fusion of spored to form diploid nuclei with DNA from different parents.
E) changes in gene expression by epigenetic changes.

Question 37

DNA sequencing analysis classifies fungi into how many distinct phyla?

A) 6
B) 4
C) 8
D) 3
E) 9

Question 38

A mycologist collects a random sample from a forest floor and identifies several hyphae among the decaying matter. This is most likely to be a

A) parasite.
B) mutualist.
C) symbiont.
D) saprophyte.
E) pathogen.

Question 39

Most fungi are adapted to living and thriving in dark environments, but some exist in areas exposed to light. Unlike fungi that live in the dark, why do many light exposed fungi have melanin in their cell walls?

A) To prevent them getting sunburnt
B) To darken their fruiting bodies, making them less likely to appear palatable to foragers
C) To help protect against UV-mediated DNA damage
D) Uupon ingestion, melanin reacts in acidic environments to produce a gastric irritant
E) All fungi can produce melanin, but when exposed to light the photons react with specialised chitin compounds to produce melanin

Question 40

Unlike most other eukaryotes, microsporidia do not have mitochondria. However, their genome contains genes that are related to mitochondrial function. This suggests that

A) mitochondrial-function genes have been transferred by viral transmission from other fungal species.
B) microsporidia used to have mitochondria but they have been lost.
C) at some stage in the past, microsporidia have fused with another fungal phyla and produced a hybrid that still carries some of the mitochondrial-function genes even though they are now non-functional.
D) microsporidia no longer produce asexually.
E) microsporidia energy requirements are not ATP driven.

Question 41

A dairy farmer has several fields full of productive, vigorous pasture including rye grass and clover. However, whenever he feeds his herd on these particular fields his cows seem to lose their balance and stagger, and soon after have reduced appetites and therefore produce less milk. What course of action should the farmer take to address this problem?

A) Aapply an insecticide to kill any tsetse flies laying eggs in the field.
B) Apply a broad-spectrum antibiotic to kill any entero-gastric bacteria present in the field.
C) Apply a monocot-specific herbicide to kill any noxious weeds.
D) Apply a dicot-specific herbicide to kill any herbs or woody seedlings harbouring toxin-producing filamentous fungi.
E) Apply a fungicide to the field to kill any endophytes living in the pasture plants.

Question 42

A home brewer accidentally heats his brew during fermentation, briefly increasing the temperature to around 65 $\degree$ C. At the end of the brewing process the brewer decides to celebrate by getting rip-roaring drunk. He drinks a dozen bottles of beer and only succeeds in feeling sick. What went wrong?

A) The temperature spike caused the ethanol to evaporate.
B) The energy pathways of yeast are temperature dependant, thus the increase in temperature caused the yeast to switch from fermenting sugars to gluconeogenesis via fatty-acid metabolism.
C) Warmer water resulted in thermal currents within the brew, displacing and disturbing the yeast culture.
D) The temperature spike killed the yeast, resulting in no ethanol production.
E) Under higher temperatures, the ethanol chemical reverts to isopropyl-alcohol.

Question 43

When ingested, alkaloids from the ergot fungus results in

A) hallucinations.
B) psychotic episodes.
C) constriction of veins and arteries.
D) gastro-intestinal irritation.
E) death.

Question 44

A scientist wants to produce a large quantity of a pectinase enzyme, which breaks down cell walls and has various industrial applications. The scientist has also identified a yeast that produces and secretes this enzyme. How would she use this fungus to produce the pectinase in industrially significant concentrations in a short time frame?

A) Grow the fungus in a fermentation vat to high numbers and purify the enzyme from the media.
B) Grow the yeast on solid media until there is a thick culture, then purify the enzyme from the media.
C) Grow the fungus in shake flasks and purify the enzyme from the media.
D) Genetically engineer the yeast to produce very high amounts of the pectinase, then grow the culture.
E) Grow several generations of the yeast, measuring pectinase output at each generation, and select for those with the highest output.

Question 45

Plant fungal pathogens account for the direct loss of what percentage of the world's food production?

A) 2%
B) 5%
C) 10%
D) 15%
E) 20%