Phylum Ascomycota (sac fungi)

Yeasts are:

common unicellular ascomycetes and include about 40 genera

Ascomycetes reproduce asexually by forming spores called....

conidia

Yeasts do not form:

conidia

Conidia form on the surface of.....

conidiophores (in contrast to spores that forms within sporangia in Rhizopus)

Ascomycota (sac fungi) includes:

yeasts, come molds, morels, and truffles

Sexual reproduction in Ascomycota (sac fungi):

1. begins with contact of monokaryotic hyphae from two mating strains 2. where hyphae touch, large multinucleate swellings appear (antheridia and ascogonia) fuse. Haploid cells intermingle in the swelling 3. a dikaryotic mycelium grows from this swelling; nuclei do not fuse immediately 4. tightly bundled dikaryotic hyphae grow and mingle with monokaryotic hyphae from each parent to form a cup-shaped ascocarp 5. dikaryotic cells lining the inside of the ascocarp form sac-shaped asci 6. nuclei fuse in each ascus to form a zygote 7. After fusion, meiosis produces 4 haploid ascopores 8. mitosis produces 8 ascospores within each mature ascus 9. the asci on the surface of the ascocarp rupture and release ascopores into the environment 10. Each ascospore can produce a new mycelium

Common examples of fungi that form conidia:

Aspergillus and Penicillium

What is Ascomycota (sac fungi) name derived from?

a microscopic, sac-shaped reproductive structure called an ascus

How do some fungal species defy classification in the major fungal phyla?

a number of fungal species produce only asexual conidia and have no known sexual phase

Most of a yeast's reproduction is:

asexual by cell fission or budding

What do conidiophores, modified, hyphae, do?

partition nuclei in longitudinal chains of beadlike conidia (each conidium contains one or more nuclei)