Mycology

Ascomycota

Largest group containing yeast, molds and a few mushrooms with asci.

Zygomycota

Includes bread molds.

Basidiomycota

Includes club fungi and mushrooms with basidia.

Characteristics of fungi

• Can be unicellular (yeast) or multicellular (mold and mushrooms)

• Cell walls consist of the polysaccharide chitin.

• The majority are saprophytes that live on dead or decaying matter or waste.

Characteristics of yeast

Unicellular with spherical or oval shape.

Yeast asexual reproduction

Through budding , which involves asymmetric division, the parent cell forms an outgrowth that detaches to form a separate daughter cell.

Yeast sexual reproduction

Through fission, a single yeast cell will undergo meiosis to form four haploid cells to divide symmetrically.

Characteristics of mold

• Multicellular

• Filamentous growth as hypha

• Macroscopic mold colony is called a thallus

• Obligate aerobes

Thallus

Composed of strands called mycelium an aggregate network of vegetative hyphae.

Phylum basidiomycota

• Multicellular

• Obligate aerobes

• Filamentous growth as hypha

• The fruiting body is called a mushroom

3 mold types

• Aspergillus

• Penicillium

• Rhizopus

Sexual spores (mold in phylum zygomycota)

Zygospores.

Asexual spores (mold in phylum zygomycota)

Sporangiospores.

Mold in phylum zygomycota

• Called conjugation fungi

• Have coenocytic hyphae

Mold in phylum ascomycota

• Called sac fungi

• Have septate hyphae

Sexual spores (Mold in phylum Ascomycota)

Ascospores, produced in a sac called ascus.

Asexual spores (Mold in phylum Ascomycota)

Conidiospores

Asexual reproduction in molds

• Asexual spores germinate giving rise to a new hypha.

• Fragmentation of the mycelium or body giving rise to a new individual organism

Sexual reproduction in molds

• Plasmogamy (hyphal preparation to cell wall removal to allow the haploid donor cell nucleus to penetrate the cytoplasm of a recipient cell.)

• Karyogamy (The fusion of the two haploid nuclei to form a diploid nucleus.)