Diversity of Eukaryotic Life: Chapter 8- Fungi

externally

Fungi are terrestrial (mostly), heterotrophic eukaryotes that digest organic C sources ____ and absorb digested molecules through their cells walls

chitin

Fungi have cells walls made of ____ (exoskeleton of arthropods such as crabs and insects)

unique polysaccharides

Chitin is a different ____ that provides support and structural rigidity to cell wall

terrestrial

Fungi are mostly ____: very few aquatic

Phylum Fungi

____ = eukaryotic organisms that digest external organic C sources and absorb digested molecules through its cell walls

decompose organic C sources

Unlike most animals, or protists that engulf their food, most fungi secret external enzymes and/or acids to ____ and smaller molecules are absorbed through cell wall.

~160,000

~ ____ species of fungi have been described and named : This is an inaccurate reflection of species diversity

1.5 millions

____ species of fungi may be found worldwide (some estimates of 6 million or more)

difficult to document all the species

In one study ~ 650 fungal species were found in the guts of 27 beetles species. Hyper-diverse communities are ____.

yeast

Using morphology, 2 growth forms are common:

• single-celled forms - ____

mycelia (singular: mycelium)

Using morphology, 2 growth forms are common:

• multicellular, filamentous forms - ____

hyphae

Mycelium is a network of fungal filaments called ____

Chitin

Cell wall of hyphae: ____

hyphal filament

Each strand of mycelium is called a ____

dynamic

All mycelia are ____: they constantly grow towards organic carbon source, slow growth or die back (dependent on water availability + quality of substrate)

many hyphae

mycelium is comprised of ____ - the long narrow hyphal filaments

septa

Filaments are divided into cells by ____ in most fungi (walls that seperate cells): pores allows cytoplasm + contents to move between cells

coenocytic

Fewer fungi have mycelia that are ____, meaning they lack septa and are a single cell (no pores = one cell + many nuclei)

(meiosis)

Fungi reproduce by sexual reproduction ____: multicellular, large and conspicuous or multicellular, small and inconspicuous.

(mitosis)

Fungi reproduce by asexual reproduction ____: multicellulars, microscopic and inconspicuous

Basidiome

____(sexual) with specialized cells that undergo meiosis to produce N spores in Basidiomycota.

Condium

____ for producing spores by mitosis shown in Ascomycota

Chytrids

____ - early diverging aquatic lineage (<1% of all fungi):

a single flagellum

Chytrids are mostly aquatic - only fungi that have____.

not monophyletic

Fungi with flagellum ____ to Chytrids.

Mucoromycota

_____ - early diverging terrestrial lineages (1%):

• hyphae are coenocytic (single cell with multiple nuclei)

  • Sexual stage (zygospore): Asexual stage (sporangium + sporangiophore)

Ascomycota and basidiomycota

____ are late diverging lineages (98%)

dikaryon

Both phyla (ascomycota and basidiomycota) with members that form a ____ with hyphae with septa (allows some contents of cytoplasm to move between cells)

dikaryotic

Hyphae are ____ (maintain two nuclei after mating): meiosis occurs in specialized cells of ascoma or basidiome

conidiophores

Asexual - stalk-like structure ____ with conidia (spores) produced by mitosis

meiosis

basidia are specialized cells that undergo ____.

meiosis

asci are specialized cells that undergo ____

Four

____ types of sexual reproductive structures in fungi

chytrids, zygospore, basidia, asci

Motile gametes and spores: ____

Chytrids

____ have spores with flagella (the only motile cells in fungi with a single flagellum), early diverging lineage reflects aquatic origin of fungi.

zygospore

Distinctive spore-producing structures of Mucoromycota called ____ (hyphae grown and mate by fusion followed by meiosis)

club-shaped hyphae

Basidiomycota or “club fungi” form basidia specialized

____ (undergo meiosis to produce haploid spores). Each basidium typically produces four spores (some exceptions)

ascospores

Ascomycota, or “sac fungi,'“ form asci reproductive sac-like cell contains ____. Each ascus typically produces eight spores (undergo meiosis followed by mitosis)

(= ascomata singular, ascoma)

Many species of Ascomycota produce large, multicellular structures ____ (cup-shaped, stalked and pitted, stalked and brain-like, flask shaped or embedded and pimple-like)

wind and rain

Ascospores typically dispersed by ____

conidia

Most fungi in the Ascomycota ( and rare in basidiomycota) produce ____ by mitosis:

• produce spores called conidia

• spores are genetically identical to the parent

• spores dispersed by wind and water

sporangium

Mucoromycota produce spores by mitosis (asexual):

• Single celled sporangiophore with ____ (many spores) produced by mitosis

zygospore

Mucoromycota produce spores by sexual reproduction:

• Sexually by ____(fusion of hyphae and two nuclei which combines to form 2N which undergoes meiosis)

lives on dead and decaying organic matter

Saprobe = an organism that ____.

specific substrates

Many fungi are saprobes found in ____(litter, soil, wood, guts of animals)

decomposition and absorption

Mycelium has large absorptive area for _____

Fungi

Only organisms that can decompose lignin (cells found in xylem)

decomposition

Saprobes are a major source of ____ since they occupy a large volume of substrate.

lignin

Wood = complex macromolecules in cell wall comprised of:

• Cellulose

• hemicellulose

• ____

symbionts

Fungi are largely important as ____

Lichens

____ = ~20,000 species;

• association between a fungus and a photosynthetic partner

mycobiont

Fungal partner obtains water and minerals; maintains the shape of a lichen to provide protection

photobiont

Photosynthetic partner (either a green algae in the Archaeplastida of Domain Eukarya or cyanobacterium in Domain Bacteria) contributes organic carbon (sugars) from photosynthesis

mutualism

Fungi is largely important in ____. Plants provide access to organic C sources derived from photosynthesis. Fungi provide access to water and nutrients from decomposition of organic C sources (nitrogen, phosphorus)

mycorrhiza

____ means fungus-root (roots of land plants = fungus)

hartig net

Ectomycorrhizae (fungi in Basidiomycota and Ascomycota) hyphae form sheath around root = ____

mantle

Ectomycorrhizae (fungi in Basidiomycota and Ascomycota) hyphae penetrates between root cells = ____.

nitrogen

Ectomycorrhizae obtain C from host. Important in ____ acquisition for both fungus + host. Commonly produce enzymes that break peptide bonds of proteins

exchange organic C source + nutrients.

Arbuscular mycorrhizae (fungi in Mucoromycota). Hyphae penetrate root cells, forms arbuscules = ____ May also form vesicles = which are used for lipid storage.

chytrid pathogen

Batrachochytrium dendrobatidis (Bd) is a ____ of amphibians (salamanders and frogs).

• responsible for the global decline and extinction of amphibians.

• Pet trade likely spread the pathogen globally

gas exchange in skin

Chytrids infect the skin which is of vital importance for their survival (amphibians exchange gases through skin). Chytrids cause disruptions of ____causing mass mortality and high rate of extinction.

carcinogen

Aspergillus flavus is a plant pathogen of crops (maize, peanut, cottonseed and tree nuts). Also produce a secondary metabolite (aflatoxin B) in the seeds that is a ____ of vertebrates

mushrooms and Quorn

People consume ____ (a vegetarian fungal protein) but we also prepare many other foods using fungi.

ferment

The yeast Saccharomyces cerevisiae is used to ____ sugar to alcohol - the process is used to make beer, wine, spirits, make bread rise

oriental foods, soy sauce and miso.

The fungi Aspergillus oryzae and Aspergillus sojae are used in the production of the ____.

flavourings, vitamins and enzymes

People use fungi to produce ____ to mature many cheeses.

preservative

Fungi can be used as ____ in a wide variety of foods; other industrial uses

citric acid

Apergillus niger is the major source of ____ production (beverages, jam/jelly, frozen food, candy, dairy products.

penicillin

Important drugs isolated from fungi include antibiotics (e.g. ____) - reduce the growth and activity of bacteria; found only in bacteria and fungi.

organ rejection after transplantation

Organ rejection drug cyclosporine A - a drug that stops ____.