Biology 109, Ch. 31: Fungi

The photosynthetic partner gives the lichen:

- carbon compounds - fixed nitrogen - nitrogen compounds

Fungi functions as: 1 - 2- 3-

1.Decomposers (saprobes) 2.Parasites 3.Mutualists

What is one key trait of all fungi?

The way they derive their nutrition

Arbuscular mycorrhizae

mycorrhizae that extend hyphae through the cell walls of root cells and into tubes formed by invagination of the root cell membrane.

The fungus gives the lichen:

- its overall shape and structure - most of its mass - a suitable growth environment - increased surface area for the uptake of gases, water, and minerals

Fungi are eukaryotes: -unicellular or multi? -terrestrial or aquatic? -reproduction? -are they more closely related to animals or plants?

- unicellular (yeasts) or multicellular (molds and mushrooms) - terrestrial or aquatic habitat - reproduction: asexual, sexual - more closely related to animals than to plants

Phylum (common name): Basidiomycota (club fungi): Reproduction: 1. Key features: 2. Examples: 3.

1. Basidiospores, sexual. 2. Basidiocarp fruiting body (mushrooms) 3. Most edible mushrooms, common button mushroom.

Phylum: Ascomycota (sac fungi): Reproduction: 1. Key features: 2. Examples: 3.

1. Conidiospores -asexual, ascus with spores - sexual 2. Ascocarp fruiting body (mushroom), yeasts, molds. 3. Morel mushroom, cup fungus

Reasons for why fungi are more closely related to animals than to plants:

1. Fungi are heterotrophs. Plants are autotrophs. 2.Fungi store excess glucose as glycogen. Plants store glucose as starch. 3. Fungal cells are made of chitin. Plants' cell walls are cellulose.

Fungi, animals, and their protistan relatives are in the supergroup _______________ and the clade _______________.

1. Unikonta 2. Opisthokonta

Chytridiomycota (chytrid fungi): Reproduction: Key features: Examples:

1. Zoospores with flagella - most asexual. Some alternation of generations. 2. Single-celled. simplest fungi, aquatic. 3. Chytriomyces hylanius

Zygomycota (zygospore fungi): Reproduction: Key features: Examples:

1. Zygospores - sexual. Sporangiospores - asexual. 2. Sporangia, gametangia saprotrophic; feed on animal remains or bakery goods. 3. Black bread mold

DNA evidence suggests that: - Fungi are most closely related to unicellular protists called _______ - Animals are most closely related to unicellular protists called ______

1. nucleariids (eg, amoeba that feed on algae and bacteria). 2. choanoflagellates

Fungal cells can be... 1. Monokaryotic cells 2. Dikaryotic cells 3. Multinucleate cells Explain each.

1. one nucleus 2. Two independent nuclei. 3. If cell division does not follow mitosis - multiple nuclei.

What do mycorrhizal fungi deliver to plants, and what do the plants provide the fungi?

1. phosphates and minerals 2. carbohydrates

Phylum: Glomeromycota (AM fungi) Reproduction: Key features: Examples:

1. spores - asexual 2. Arbuscules, symbiotic with plants. 3. Glomerales

Mycelia

An interconnected mass of hyphae that are adapted for absorption. A mycelium's structure maximizes its surface-to-volume ratio.

What is the largest organism on earth?

Armillaria ostoyae. It lives in Oregon, covers ~2000 acres and is ~2000 years old.

Where does meiosis occur in a mushroom?

Basidia

Why are fungi essential for the well-being of most terrestrial ecosystems?

Because they break down organic material and recycle vital nutrients (ie, decomposers).

What makes up fungal cell walls

Chitin

Pores

Each septum contains at least one pore, which enables nutrients and other cell contents to flow between cells.

Fungi are autotrophs and absorb nutrients from outside of their bodies. (T/F).

False. Fungi are HETEROTROPHS and absorb nutrients from outside of their bodies.

The morphology of multicellular fungi does not enhance their ability to absorb nutrients (T/F)

False. It does

Mycelium is directly involved in the reproduction of at least one major group of fungi (T/F)

False. The Mycelium is only the network of filaments that makes up the body of the fungus.

Fungi are heterotrophic eukarotes that include only yeast and molds (T/F)

False. They also include mushrooms

Most of the cells in a mushroom contain diploid nuclei (T/F)

False. They are mostly haploid

Molds are filamentous fungi that produce diploid spores and form visible mycelia (T/F)

False. They produce haploid spores.

What is a key difference between fungi and plants?

Fungi are heterotrophic, and plants are autotrophic.

The most common body structures of fungi

Hyphae -multicellular filaments Yeasts -single cells

Heterokaryon

In most fungi, the haploid nuclei from each parent do not fuse right away; they coexist in the mycelium.

Dikaryotic

In some fungi, the haploid nuclei pair off two to a cell; such a mycelium is said to be this

Where do mycelia release digestive enzymes?

In the surroundings. They break down macromolecules in leaves and decaying matter liberating smaller sub-units like sugars and amino acids.

Deuteromycetes (second fungus)

Many molds and yeasts that are known to have no sexual stage. Mycologists have traditionally called these "imperfect fungi".

What events occurs first in the development of a spore into a mature mushroom?

The spore undergoes mitosis to produce hyphae

Fungal cells are normally haploid, except when transient diploid stages form during the sexual life cycle (T/F)

True

Fungi are heterotrophs and absorb nutrients from outside of their bodies (T/F)

True

In most fungi, fertilization is a two-step process consisting of the fusion of cells and then the fusion of nuclei in the fused cells (T/F)

True

Most vascular plants have mycorrhizae. (T/F)

True

Nutrients absorbed by the hyphae can flow throughout the mycelium in both coenocytic hyphae and septate hyphae (T/F)

True

Some fungal species grow as either filaments or yeasts; others grow as both (T/F)

True.

Yeasts do not produce spores. Instead, they undergo budding (T/F)

True.

Fungi obtain nutrients through...

absorption

Ergotism

caused by Claviceps purpurea (ergot of rye), is characterized by nervous spasms, burning sensations, hallucinations, and temporary insanity.

Septa (septate hyphae)

divides a hypha into cells.

Practical uses of fungi

food and antibiotics

Mycosis

fungal infection in animals

Coenocytic (or aseptate) fungi

fungi that lacks septa and have a continuous cytoplasmic mass with hundreds or thousands of nuclei.

Karogamy

fusion of nuclei, resulting in a diploid cell

Basidia

hyphae that generate in the gills of mushrooms that produce spores

Endophytes

inside the plant - mutual relationship between fungi and plants -> makes toxins against herbivores and pathogens.

Basidia produce spores by a process known as

meiosis

Lichen

mutualistic association between a photosynthetic microorganism and a fungus (usually an ascomycete).

Mycorrhizae

mutually beneficial relationships between fungi and plant roots.

Ectomycorrhizae

mycorrhizae that forms sheaths around the root and grow into the extracellular spaces of the root cortex.

Which term describes the fusion of cytoplasm from two individuals?

plasmogamy

Pheromones

signaling molecules that are released to detect different mating types so that they can reproduce sexually through the fusion of their hyphae

Exoenzymes

what fungi use to break down a large variety of complex molecules into smaller organic compounds.