24.2 Classifications of Fungi

Question 1

Major phyla

Answer 1

• there are 5 major phyla which are classified by sexual reproduction or molecular data
• 1 extra phyla for polyphyletic unrelated fungi without a sexual cycle known as “FORM FUNGI” sequencing of 18s rRNA show different relationships

Question 2

Deuteromycota

Answer 2

was a whole category for fungi that only rerpduce asexually however now it is no longer in use.
fungi imperfecti

• commonly known as mold
• reproduce asexually with conidiospores
• cheese ripening and other stuff

Question 3

Vocabulary

Answer 3

-mycota (phylum)
- mycetes (class or all members of a phylum)

Question 4

5 Major phyla names

Answer 4

• Chytridiomycota (Chytrids)
• Zygomycota (Cojugated fungi)
• Ascomycota (Sac fungi)
• Basidiomycota (Club fungi)
• Glomeromycota (Mycorrhizae)

Question 5

Chytridiomycota (chytrids)

Answer 5

• only 1 class (chytridiomycetes)
• simplest most promitive true fungi (eumycota)
• Chitin in the cell wall // one group has cellulose
• mostly unicellular or coenocytic
• Gametes and diploid zoospores that swim
• Are aquatic
• Are parasitic on land

Question 6

Zygomycota (conjugated fungi)

Answer 6

• Mainly saprobes (few parastic for insects)
• Synthesize semisynthetic steroids
• Have a thallus of coenocytic hyphae
  
  • Haploid nucleius in vegetative
  • asexually reproduce with sporangiospores

Question 7

Zygomycota (sexual reproduction)

Answer 7

• Occurs in unfavorable condtions
• Opposing mating strains (+ & -) are in close proximity

1) gametangia of opposing strains plasmogamy
2) forms a zygosporangium
3) zygosporangium goes through karyogamy
4) Meiosis and fermentation leads to growth of a sporangium
5) sporangium disseminates spores.

• diploid zygospores have a thick coat
• they remain dormant till conditions are favorabple
• germination leads to meoisis and then growth since hyphae is haploid

Question 8

Ascomycota (sac fungi)

Answer 8

• characterized by formation of an ascus (sac for haploid ascospores)
• majority of known fungi
• Baker’s yeast and more
• Filamenous ascomycetes produce hyphae with perforated septa
• conidia (asexual) and asci (sexual)
  
  • separated by blocked septa

Question 9

Ascomycota (Sexual reproduction)

Answer 9

Asexual reproduction is frequent
- Produces conidiophores (that release haploid conidospores)

Sexual reproduction
Male = antheridium / Female = Ascogonium

1) Plasmogamy occurs between the antheridium and ascogonium
2= mitosis and cell division grows and creates the ascocarp (fruiting body)
3) Karyogamy occurs at the tip of the ascocarp forming the ascus which is diploid
4) the ascus undergoes meiosis
5) the ascus undergoes mitosis and cell dicision now having 8 haploid ascospores inside of it,
6) the ascus disseminates the spores
7) spores germinate

Question 10

Basidiomycota (club fungi)

Answer 10

• club-shaped basidia (fruiting body)
• swollen hypae as the terminal cell
• most of the edible fungi are here

Sexual reproduction via Alternation of Generations

1) Basidiospores (haploid) germinate to make + and - mating type mycelia
2 ) Gametangia undergo plasmogamy
3) Mitosis occurs and creates a fruiting body (basidiocarp with basidia cellls)
4) The basidia cells then undergo karyogamy
5) the zygote undergoes meiosis forming the basidium
6) the basidium undergoes cell division (basidiospore formation)
7) dispersial off spores and germination

Question 11

Glomeromycota

Answer 11

• are at the roots of trees forming arbuscular mycorrhizae
• plant gives the fungi carbon
• fungi gives the plant essential minerals that are in soils
• they do not sexually reproduces and are not alive without the roots
• do not have zygospores but are coenocytic like the zygomycetes
• are from a monophyletic lineage (all from one)