Ch. 25

True or false: Because they grow in soil and produce mushrooms above ground, fungi are more similar to plants than they are to animals.

True or false: Because they grow in soil and produce mushrooms above ground, fungi are more similar to plants than they are to animals.

False

Fungal filaments are called

hyphae

The cytoplasm of fungal cells can exhibit a characteristic flow. Where is this flow observed?

Throughout the hyphae, as cytoplasm passes through pores in the septa

In some species, fungal hyphae do not have septa and contain multiple nuclei. Such hyphae are called ___ hyphae.

coenocytic

Fungal hyphae are very long but only grow at their tips. How can they achieve such rapid growth?

Because of cytoplasm streaming, proteins synthesized throughout the hyphae can be quickly transported to the growing tips.

When compared with other multicellular eukaryotic organisms, fungi are described as which of the following?

More similar to animals than they are to plants

Which describes mycelium?

A mass of connected hyphae

Which of the following best describes hyphae?

Long chains of cells joined end-to-end and divided by cross-walls with pores.

The cell walls of fungi are composed of the polysaccharide

chitin

Which of the following is a characteristic of the cytoplasm in fungal cells?

Their cytoplasm streams freely throughout the hyphae, because it can pass through larger pores in the septa.

When a fungus undergoes mitosis, which of the following occurs?

The spindle apparatus forms within the nucleus.

Which statement about fungal cells is true?

They may have one, two, or more nuclei

Many fungi can reproduce by making both sexual and asexual

spores

What is one unique evolutionary advantage of the unique multicellularity of fungi?

Free cytoplasmic flow due to pores in septa allows them to very rapidly make use of nutrients encountered in the environment.

A mass of connected ___ is called a mycelium.

hyphae

In some fungi, namely the basidiomycetes and ascomycetes, an intervening ___ stage occurs after fusion of two haploid cells and before the parental nuclei fuse to form a diploid nucleus.

dikaryotic

Fungal cell walls are made of ____.

chitin

Mitosis in multicellular fungi differs from that of other organisms in which way?

It is not followed by cell division.

How do fungi reproduce?

Both sexually and asexually

The aboveground portion of a fungus, such as a mushroom, is which of the following?

Reproductive structure

Fungal spores ____.

can be produced through sexual or asexual reproduction

The dikaryon stage occurs primarily in which of the following fungi?

Ascomycetes

Basidiomycetes

Fungi are ____.

heterotrophs

What does the structure of a mycelium accomplish in terms of fungal feeding?

It provides a high surface area for the absorption of organic molecules, water, and minerals.

What are you looking at when you see a fungus growing above the ground in forest soil?

The reproductive structures

The main decomposers in the biosphere are ____.

bacteria and fungi

The most common means of reproduction in fungi is through the production of

spores

If a symbiotic fungus can survive without its host, this relationship is described as a(n) ___ symbiosis.

facultative

A symbiotic fungus that obtains resources from its host, but does not cause disease, is called a(n)

parasite

A fungus typically obtains food by secreting extracellular digestive ___, which break down organic molecules.

enzymes

Which of the following describes a relationship which benefits one partner without harming the other?

Commensalism

How does the structure of a mycelium allow for maximum absorption of nutrients?

Narrow, branching hyphae provide a large absorptive surface area.

What are fungal endophytes?

Fungi that live within tissues of other organisms

Fungi and bacteria are important in most ecosystems because of their role as ____.

decomposers

A lichen consists of an association between a fungus and which of the following?

Cyanobacterium or green alga

If a symbiosis is essential for survival, it is described as a(n) ___ symbiosis.

obligate

Describe the fungi in lichens.

It can not grow normally without their photosynthetic partners.

A symbiotic fungus that causes disease in its host is described as a(n)

pathogen

A relationship that benefits both a symbiotic fungus and its host is said to be

mutualistic

Fungi that live within the leaf and stem tissues of plants without causing disease, are known as fungal

endophytes

Select all possible living components of a lichen.

Fungus

Green alga

Cyanobacterium

In a lichen, the fungal partner does which of the following?

Penetrates the cell wall, but not plasma membrane, of the photosynthetic partner

What are mycorrhizae?

Associations between the hyphae of certain fungi and the roots of plants

Mycorrhizal relationships provide plants with

minerals

In a mycorrhizal relationship, the host ___ produces organic nutrients for use by the ___.

plant; fungus

Mutualistic associations between the hyphae of certain fungi and the roots of most seed plants are known as

mycorrhizae

Which type of mycorrhizae grows on the surfaces of tree roots, but not beyond the of walls of the root cells?

Ectomycorrhizae

Select all characteristics of ectomycorrhizae.

-The fungal component is usually a basidiomycete.

-Most plant hosts are forest trees such as pines, oaks, and birches

Which member of a mycorrhizal relationship benefits through improved uptake of nutrients?

Plant

What benefit do mycorrhizal fungi receive from their plant partners?

Organic nutrients

Fungi have formed mutualistic symbioses with which of the following?

Some animal species, such as ants and ruminants

Why is treating fungal diseases in animals particularly difficult?

Fungi are phylogenetically related to animals

Which of the following has hyphae that grow in the space between the cell wall and the plasma membrane of a plant cell?

Arbuscular mycorrhizae

Carcinogenic compounds produced by some Aspergillus flavus strains are called

aflatoxins

Compared to the arbuscular mycorrhizae, the ___ involve far fewer species of plants.

ectomycorrhizae

Traditionally, fungi were divided into four phyla based primarily on which characteristic?

Meiosis

Select all examples of mutual symbioses between fungi and animals.

-Leaf cutters ants that cultivate fungi

-Fungi in the guts of ruminant animals

In 2007, mycologists agreed to classify all fungi into seven phyla: _, Blastocladiomycota, Neocallimastigomycota, Chytridiomycota, _, Basidiomycota, and Ascomycota.

Glomeromycota; Microsporidia

It is often more difficult to treat human diseases caused by fungi than those by bacteria because ____.

both humans and fungi are eukaryotes

Based on DNA evidence showing the presence of mitochondrial genes, microsporidia have been moved to the fungal kingdom from which of the following?

Protist kingdom

Select all effects of aflatoxins.

Kidney damage

Nerve damage

Cancer

Blastocladiomycetes, neocallimastigomycetes, and chytridiomycetes were originally grouped as a single phylum, based on which of the following feature?

Presence of flagellated zoospores

Select the feature that distinguishes the chytridiomycota and relatives from the other groups of fungi.

Flagellated spores

Select the four traditional fungal phyla.

Zygomycota

Basidiomycota

Ascomycota

Chytridiomycota

Select all true statements about blastoclads.

They produce zoospores.

They are parasitic.

They have a haplodiplontic life cycle.

Which of the following is not a fungal group?

Poriferamycota

Microsporidia have been tentatively moved from the protists to the fungi based on which of the following?

Analysis of DNA sequence data

Until DNA evidence provided evidence to the contrary, flagellated spores were used to group the blastocladiomycetes with the ____.

chytrids

Chytridiomycota are distinguished from other fungi because they possess flagellated ___, released from a specialized structure called a chytridion.

zoospores

Which of the following is a feature of Blastocladiomycota?

Alternation of multicellular haploid and diploid life cycles

Select all true statements about neocallimastigomycetes.

-They are anaerobic.

-They produce zoospores with multiple flagella

Zygomycetes have cell walls that contain a modified form of chitin called

chitosan

Zygomycete asexual spores are contained in which structure?

Sporangia

Which phylum contains fungi that are anaerobic and use hydrogenosomes instead of mitochondria.

Neocallimastigomycota

Which of the following are glomeromycetes?

Mycorrhizae

How does the primary mycelium in Basidiomycota differ from that of the secondary mycelium?

The primary mycelium is made up of monokaryotic hyphae, while the secondary mycelium is composed of dikaryotic hyphae.

With the exception of their gametangia, the hyphae of zygomycetes

lack septa

Which of the following contain truffles and morels?

Ascomycetes

Zygomycete sporangia contain which of the following?

Thin-walled asexual spores

Which of the following best characterizes the hyphae of ascomycetes?

The hyphae are divided by septa with pores.

Select all true statements about the Glomeromycota.

They do not undergo sexual reproduction.

They form arbuscular mycorrhizae.

The basidiomycete mycelium composed of monokaryotic hyphae is called the ___ mycelium, while that containing dikaryotic hyphae is called the ___ mycelium.

primary; secondary

What are truffles and morels?

Edible fruiting bodies of ascomycetes

In ascomycetes, hyphae are ______.

separated by perforated septa and cytoplasm flows along the length of each hypha

Ascomycetes produce sexual spores within a sac called a(n)

ascus

True or false: The unicellular ascomycetes, yeast, cannot form ascospores.

False