Korean, Edit

Chapter 27. Fungi

Recommended Article : 【Biology】 Table of Contents for Biology

1. Characteristics

2. Life Cycle

3. Classification

1. Characteristics

⑴ Multicellular Eukaryotic Organisms

① Exception : Yeast

② Multinucleate Fungi → Septa → Multicellular Mycelium

⑵ Lack Chlorophyll, Depend on Heterotrophic Nutrition

① Extracellular Digestion : Absorption through Hyphae

② Symbiosis 1. Lichen-forming Fungi : Symbiosis with Algae (Plants), Cyanobacteria (Bacteria), and Green Algae (Protists)

③ Symbiosis 2. Mycorrhizae : Fungi + Plants (Eukaryotic)

⑶ Composed of Mycelium : Body, Reproductive Structures

① Mycelium : Structure formed by elongated cells resembling threads

② Aggregation of Mycelium forms Mycelial Structure

⑷ Cell Organelles

① Cell Organelles are enclosed by the Cell Membrane

② Cell Membrane : Composed of Ergosterol

③ Cell Wall : Composed of Chitin, Glucan

⑸ Classification Based on Presence of Septa

① Septa : Walls between cells, containing pores large enough for nuclei to pass through

② Zygomycota, Chytridiomycota : No Septa

③ Ascomycota : Partial Septa

④ Basidiomycota : Septa Present

⑹ Production of Useful Substances like Antibiotics

2. Life Cycle

⑴ 1^st. Plasmodium (n)

⑵ 2^nd. (+) Mating Type (n) and (-) Mating Type (n) Fuse to Form Diploid Nucleus (2n)

⑶ 3^rd. Spore (n) Formation

① Zygomycota, Chytridiomycota : Diploid → Fusion → Meiosis

② Ascomycota : Diploid → Cell Division → Fusion → Meiosis, 8 Spores / Ascus

③ Basidiomycota : Diploid → Cell Division → Fusion → Meiosis, 4 Spores / Basidium

⑷ 4^th. Spore (n) Mitosis → Formation of Plasmodium (n)

Figure 1. Life Cycle of Fungi

3. Classification

⑴ Chytridiomycota (Chytrids)

① Earliest Fungi

② Zoospores (Animal-like Spores)

⑵ Zygomycota (Zygomycetes) (e.g., Bread Molds)

① Aseptate Hyphae

② Sexual Reproduction produces Zygosporangium

③ Zygospore : Result of Plasmogamy of Zygote (2n)

⑶ Mycorrhizae

① Symbiosis with Plants

② Ectomycorrhizae : Observed in 10% of Plants

○ Ectomycorrhizal Hyphae form a tough mantle over the root surface

○ Some Hyphae penetrate the outer cells of the root but do not enter the cell walls

③ Endomycorrhizae : Observed in 85% of Plants

○ Endomycorrhizal Hyphae grow into the root and do not form a mantle

○ Some Hyphae penetrate root cells, but not the cell membrane

④ Mycorrhiza → Plant : Mycorrhiza provides Plants with nutrients like NO3- or H2PO4-

⑤ Plant → Mycorrhiza : Plants provide Mycorrhiza with photosynthesis products, such as sugars

⑷ Ascomycota (Sac Fungi) (e.g., Yeasts, Molds)

① Ascocarp (n) develops during Sexual Reproduction

② Ascospores : Spores formed within the Ascus (n)

③ Conidiospores: Used during Asexual Reproduction, while Ascospores are used during Sexual Reproduction

④ Yeasts can form Ascospores under unfavorable conditions

⑤ Symbiosis with Algae

⑸ Basidiomycota (Club Fungi) (e.g., Mushrooms)

① Aggregated Mycelium forms Basidiocarp, Basidiospores formed in Basidium

② Basidiospores : Spores formed within Basidium on the Basidiocarp

③ Decompose Lignin in Wood for Survival

④ Dikaryotic Mycelium divides to form Mushroom, Basidium

Input: 2019.03.17 11:00