MICROIMM Lec 29: Mycology Intro

Between plants and fungi, which came first?

Plants

Are fungi more closely related to humans or plants?

Humans

What are prototaxites?

A fungi, existed millions of years ago

What are the dimensions that prototaxites can grow to be?

1m wide, 8m tall

What organism is believed to be the largest on earth?

Armillaria (a genus of fungi)

One organism of Armillaria can cover how much area?

Hectres of land

Are fungi cells more closely related to mammalian or plant cells?

In between, but closer to mammalian cells

In plants, the cell wall is made of...

cellulose

What are the subunits/monomers that make up cellulose?

glucose

What type of linkage connects the glucose monomers in cellulose?

B(1-->4) linkages

What is the most prevalent polysaccharide on earth?

cellulose

In fungi, the cell walls are made of...

chitin

In what other things is chitin found in?

Insects, mollusks

What monomers make up chitin?

N-acetylglucosamine

What type of linkages are in chitin?

B(1-->4) linkages

In acetylglucosamine, what are the hydroxyl groups of glucose replaced by?

amine joined to acetyl group

Does glucose and acetylglucosamine have the same physical properties?

No

How many nuclei are present in plant cells?

one

How many nuclei are present in fungi cells?

may be uninucleated or multinucleated

Are plant cells autotrophs or heterotrophs?

Autotrophs

Define autotroph

Organism that has the ability to make its own energy through photosynthesis

Are fungal cells autotrophs or heterotrophs?

Heterotrophs

Define heterotroph

Organisms that obtain energy by consuming other living things

Plant cell membranes contain _____

phytosterols

Fungi cell membranes contain _____

ergosterol

Human cell membranes contain _____

cholesterol

What do plant cells store their food as in granules?

Starch

What do fungi cells store their food as in granules?

glycogen

How many forms of starch are there?

2

Is amylose branched or unbranched form of starch?

unbranched

What form does amylose create with its 1-->4 glycosidic linkages?

helical structure

Is amylopectin branched or unbranched?

Branched

What bonds can amylopectin do?

a(1-->4) glycosidic bonds

a(1-->6) glycosidic bonds

Does glycogen have more or less branches compared to starch?

more branched

When fungi form spores, do they share the same or unique structures?

Unique

Name the 3 classes of fungi based on modes of nutrition

1. Saprophytic

2. Parasitic

3. Symbiotic

Define saprophytic species

The fungi obtains their nutrition by feeding on dead organic substances

Name an example of saprophytic fungi

Aspergillus/Penicillium

What do the fungi release to break down and feed on the dead decaying organic vegetation?

Different enzymes

What enzyme does the fungi release to break down proteins?

proteases

What enzyme does the fungi release to break down lipids?

lipases

What enzyme does the fungi release to break down sugars/starch?

amylase

How does the fungi bring in the broken down material into the cell?

Endocytosis

Define parasitic fungi

The fungi obtains their nutrition by living on other living organisms (plants or animals) and absorb nutrients from their host

Do parasitic fungi release enzymes?

No (the host breaks the nutrients down)

Name an example of a parasitic fungi

Puccinia

Puccinia is a type of ____ that forms on plants

rust

Why is rust on plants considered dangerous?

Causes blight; can wipe out crops

Define symbiotic fungi

These fungi live by having an interdependent relationship with other species in which both are mutually benefited

Name 2 examples of symbiotic fungi

lichens, mycorrhiza

What organisms are involved in the symbiotic relationship with lichen?

Fungus + algae

What component of wolf lichen is used to keep wolves and foxes away?

the toxic pigment

What organisms are involved in the symbiotic relationship with mycorrhiza?

Fungus + plant

What two forms are under filamentous fungi?

macrofungi, microfungi

Between macrofungi and microfungi, which is the usual edible form?

macrofungi

What is another term for filamentous macrofungi?

fruit body

Do all fungi produce fruit bodies?

No

What term is microfungi commonly known as?

Mold

Are microfungi unicellular or multicellular?

Unicellular

What is the most common method of fungal reproduction?

Asexual

Define anamorphs

Fungi undergoing asexual reproduction

Define spores

asexual propagules produced to continue replicating/reproducing

When are spores produced during asexual reproduction?

Following mitosis

Define teleomorphs

Fungi undergoing sexual reproduction

How are sexual propagules produced?

By the fusion of two nuclei (diploid) that then generally undergo meiosis

Do fungi have male and female gametes?

No

Does fungal sexual reproduction have a crossover event?

Yes

Between asexual and sexual reproduction, which one produces more genetic diversity?

Sexual

Define parasexual reproduction

Involves genetic recombination without the requirement of specific sexual structures

Is genetic recombination possible with parasexual reproduction?

yes

In filamentous fungi, what is responsible for releasing the spores?

the fruitbody

What conditions are required for the spores to germinate in the soil?

Correct moisture, if food is present

What are hyphae?

threadlike filaments that make up fungal bodies; produced by spores after germination

What is mycellium?

network of hyphae

Where does mating between different hyphae occur?

in the soil

What is pinning?

The formation of young mushrooms from the mating of hyphae

For filamentous fungi species that don't produce fruitbody, where do they reside after germination?

in the soil

What is the vegetative growth phase?

in the soil phase

Hyphae filaments extend only at...

their extreme tips

Define septate

Division between each of the cells; walls separate each cell

In septate, how many nuclei does each cell have?

One or multiple

Define coenocytic

No division between the cells

WIth coenocytic fungi, the ____ can move freely between the cells, along the structure

cytoplasm, organelles, nuclei

Fungi exhibit ____ growth in contrast to many other filamentous organisms

apical

What happens to the older sections of the mycelium?

Dies if there is no proper nutrition

Fungal hyphae branch repeatedly behind/in front of their tips

behind

Does Aspergillus Nidulans life cycle have sexual, asexual, or parasexual reproduction?

All three

In Aspergillus, is the hyphae septate or coenocytic?

Septate

What is the conidiophore?

Structure formed from the septate hyphae to release the spores

What is the ploidy of the spores?

Haploid

What factors carry the spores away from the conidiophore?

Wind, animals, etc

What is the conidium?

asexual spore

What does a spore form?

Germinates (under the right conditions) to form a new network of mycelium

When does asexual reproduction occur to produce spores?

In the conidiophore structure

In sexual reproduction, do hyphae cross with themselves or other species?

Can do both

How do the structures differentiate between male and female mating types?

Genetic element present in the nuclei identify themselves as male or female mating types

Explain how sexual reproduction occurs in hyphae

Two nuclei of different mating types fuse together

After the fusion event, what is the ploidy?

Diploid

The diploid structure undergoes ____ to release four progeny

meiosis

The four progeny each undergo mitosis how many times?

once