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Fungi

Fungi flashcards
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Nutrition
Fungi are heterotrophs - they cannot make their own food

Unlike animals fungi do not ingest (eat) their food

Absorbs nutrients from the environment

They do this by secreting enzymes
Structure
The most common fungal body structures are multicellular filaments and single cells called yeasts.
Yeasts
Single Celled Fungi

Relatively few species of fungi grow as these
Hyphae
Tiny filaments that form bodies of fungi

Consist of tubular cell walls surrounding the cytoplasm of the cells
Chitin
Unlike plant cell walls, fungal cell walls are strengthened by this.
Mycelium
An interwoven mass formed by fungal hyphae
Septa
In most fungi, the hyphae are divided into cells by cross walls, known as this.

These generally have pores large enough to allow ribosomes, mitochondria, and even nuclei to flow from cell to cell.

Some fungi lack this.
Coenocytic Fungi
Fungi lacking Septa.

Consist of a continuous cytoplasmic mass having hundreds or thousands of nuclei

Results from repeated division of nuclei without cytokinesis
Haustoria
Specialized hyphae

Fungi use to extract nutrients from - or exchange nutrients with - their hosts
Mycorrhizae
Mutually beneficial relationships between fungi with Haustoria and plants are called this.
Ectomycorrhizal fungi
Mycorrhizae fungi that form sheaths of hyphae over the surface of a root and also grow into the extracellular spaces of the root cortex
Arbuscular Mycorrhizal fungi
Mycorrhizae fungi that extend their branching hyphae through the cell wall and into tubes formed by invagination (pushing inward) of the root cell membrane
Reproduction in Fungi
Both sexually and asexually
Sexual Reproduction
The nuclei of fungal hyphae and the spores of most fungal species are haploid, although many fungi have transient diploid stages that form during sexual life cycles. Generally ____________ occurs when two mycelia release sexual signaling molecules called pheromones.
Pheromones
(Sexual Reproduction)

A sexual signaling molecule secreted from hyphae.

Begins sexual reproduction
Plasmogamy
(Sexual Reproduction)

The union of the cytoplasms of two parent mycelia
Heterokaryon
(Sexual Reproduction)

In most fungi, the haploid nuclei contributed by each parent do not fuse right away. Instead parts of the fused mycelium contain coexisting, genetically different nuclei.
Dikaryotic
(Sexual Reproduction)

"Two Nuclei"

When haploid nuclei pair off two to a cell, one from each parent.
Asexual Reproduction
Reproduction (non-sexual)

As many as 20,000 fungal species are known to reproduce this way
Molds
Many fungi reproduce asexually by growing as filamentous fungi that produce (haploid) spores by mitosis; such species are known informally as _________ if they form visible mycelia.

Sometimes found in kitches, fruit, bread, and other foods
Deuteromycetes
Term for many yeasts and filamentous fungi which have no known sexual stage.

Mycologists have given such fungi this name.
Opisthokonts
A clade formed by fungi, the animals, and their protistan relatives.

The name of this clade refers to the posterior location of the flagellum in these organisms
Chytrids
Example: Chytridium

Globular fruiting body forms multicellular, branched hyphae.

Other species can be single-celled.

Thought to be one of the earliest fungal groups to diverge from other fungi
Zygomycetes
Example: Mucor

The hyphae of some ______________ grow rapidly into foods such as fruits and bread.

The fungi may act as decomposers (if the food is not alive) or parasites; other species live as neutral (commensal) symbionts.
Glomeromycetes
(Arbuscular mychorrhizal fungi)

Great ecological importance.

Many plants form mychorrhizal associations with these fungi.
Ascomycetes
Example: Aleuria aurantia

Also called sac fungi

Members of this diverse group are common to many marine, freshwater, and terrestrial habitats.
Basidiomycetes
Example: Amanita muscaria (a type of mushroom)

Often important as decomposers and ectomycorrhizal fungi.

Club fungi

Are unusual in having a long-lived, dikaryotic mycelium.
Decomposers
________________ will absorb organic material, including the cellulose and lignin of plant cell walls.
Endophytes
Symbiotic fungi that live inside leaves or other plant parts without causing harm.

All plant species studied to date appear to harbor symbiotic ________.
Lichen
Symbiotic association between a photosynthetic microorganism and a fungus in which millions of photosynthetic cells are held in a mass of fungal hyphae.
Soredia
Small clusters of hyphae with embedded algae

As might be expected of "dual organisms," sexual reproduction as a symbiotic unit also occurs commonly, either by fragmentation of the parental lichen or by the formation of ________.
Mycosis
The general term for a fungal infection.
Practical Use of Fungi
Antibiotics, Foods, Alcohol, Research in molecular biology and biotechnology.
B. Heterotrophic
All Fungi share which of the following characteristics?
A. Symbiotic
B. Heterotrophic
C. Flagellated
D. Pathogenic
E. Act as decomposers
C. Flagellated Spores
Which feature seen in chytrids supports the hypothesis that they diverged earliest in fungal evolution?
A. The absence of chitin within the cell wall
B. Coenocytic hyphae
C. Flagellated spores
D. Formation of resistant zygosporangia
E. Parasitic lifestyle
D. Conidiophores
Which of the following cells or structures are associated with asexual reproduction in fungi?
A. Ascospores
B. Basidiospores
C. Zygosporangia
D. Conidiophores
E. Ascocarps
E. An extensives surface area well suited for invasive growth and absorptive nutrition.
The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to
A. the ability to form hausoria and parasitize other organisms.
B. avoiding sexual reproduction until the environment changes.
C. the potential to inhabit almost all terrestrial habitats.
D. the increased probability of contact between different mating types.
E. an extensive surface area well suited for invasive growth and absorptive nutrition.
B. A green alga
The photosynthetic symbiont of a lichen is often
A. A moss
B. A green alga
C. A brown alga
D. An ascomycete
E. A small vascular plant
A. Animals
Among the organisms listed here, which are thought to be the closest relatives of fungi?
A. Animals
B. Vascular plants
C. Mosses
D. Brown algae
E. Slime molds