Biology Lecture 12: Fungi General Features

Fungi General Features

• Fungi belong to the domain Eukarya and kingdom Fungi.
• They range in size from single-celled yeast to 3-mile-wide honey mushrooms.
• Fungi lack chlorophyll and have cell walls made of chitin (a polymer of N-acetylglucosamine).
• They have absorptive nutrition, secreting enzymes to break down nutrients.
• Fungi are essential decomposers, breaking down complex organic compounds like cellulose.
• Without fungi, dead plants and trees would accumulate, and plant and human life would cease.

Fungi Terms

• Mycology is the study of fungi.
• Mycoses are diseases caused by fungi.
• Mycotoxicosis is poisoning by fungal toxins, such as aflatoxins, which are carcinogens.

Fungi Distribution

• Fungi are mostly terrestrial, but some are aquatic.
• They can be part of human microflora and can form associations with other organisms, like lichens (fungi and cyanobacteria) and mycorrhizal fungi and plants.
• Examples of mycorrhizal fungi and plants include truffles.

Yeasts and Molds

• Yeasts are unicellular fungi, such as Saccharomyces cerevisiae (used in bread, beer, and wine) and Candida albicans (found in the mouth, vagina, and intestinal tract).
• Molds are multicellular fungi, such as Aspergillus, with hyphae (filaments) and mycelium (a mass of hyphae).
• Some fungi can change from yeast to mold form, known as the yeast-mold shift.

Fungi Reproduction

• Asexual reproduction involves binary fission, budding, and spore production, resulting in offspring genetically identical to the parent.
• Sexual reproduction involves the fusion of haploid cells of opposite mating types, resulting in a diploid zygote that undergoes meiosis to form haploid spores.

Fungi Subclasses

• Chytridiomycetes are simple fungi with motile flagellated zoospores, often found in aquatic environments.
• Zygomycetes (Mucormycota) have sexual zygospores and asexual sporangiospores, and include species like Rhizopus (used in meat tenderizer and birth control agents).
• Ascomycota (sac fungi) produce sexual ascospores and asexual conidiospores, and include species like Aspergillus and Penicillium.
• Basidiomycota (club fungi) produce sexual basidiospores and include species like mushrooms and Cryptococcus neoformans (a pathogen in immunocompromised individuals).

Fruiting Bodies and Spores

• Fruiting bodies, like mushrooms, produce spores for reproduction.
• Ascomycota produce asci, containing sexual ascospores, while Basidiomycota produce basidia, bearing sexual basidiospores.
• Examples of Basidiomycota include edible mushrooms (Agaricus) and deadly species like Amanita (containing the toxin Amanitin).

Fungi General Features

• Fungi belong to the domain Eukarya and kingdom Fungi.
• They range in size from single-celled yeast to 3-mile-wide honey mushrooms.
• Fungi lack chlorophyll and have cell walls made of chitin (a polymer of N-acetylglucosamine).
• They have absorptive nutrition, secreting enzymes to break down nutrients.
• Fungi are essential decomposers, breaking down complex organic compounds like cellulose.
• Without fungi, dead plants and trees would accumulate, and plant and human life would cease.

Fungi Terms

• Mycology is the study of fungi.
• Mycoses are diseases caused by fungi.
• Mycotoxicosis is poisoning by fungal toxins, such as aflatoxins, which are carcinogens.

Fungi Distribution

• Fungi are mostly terrestrial, but some are aquatic.
• They can be part of human microflora and can form associations with other organisms, like lichens (fungi and cyanobacteria) and mycorrhizal fungi and plants.
• Examples of mycorrhizal fungi and plants include truffles.

Yeasts and Molds

• Yeasts are unicellular fungi, such as Saccharomyces cerevisiae (used in bread, beer, and wine) and Candida albicans (found in the mouth, vagina, and intestinal tract).
• Molds are multicellular fungi, such as Aspergillus, with hyphae (filaments) and mycelium (a mass of hyphae).
• Some fungi can change from yeast to mold form, known as the yeast-mold shift.

Fungi Reproduction

• Asexual reproduction involves binary fission, budding, and spore production, resulting in offspring genetically identical to the parent.
• Sexual reproduction involves the fusion of haploid cells of opposite mating types, resulting in a diploid zygote that undergoes meiosis to form haploid spores.

Fungi Subclasses

• Chytridiomycetes are simple fungi with motile flagellated zoospores, often found in aquatic environments.
• Zygomycetes (Mucormycota) have sexual zygospores and asexual sporangiospores, and include species like Rhizopus (used in meat tenderizer and birth control agents).
• Ascomycota (sac fungi) produce sexual ascospores and asexual conidiospores, and include species like Aspergillus and Penicillium.
• Basidiomycota (club fungi) produce sexual basidiospores and include species like mushrooms and Cryptococcus neoformans (a pathogen in immunocompromised individuals).

Fruiting Bodies and Spores

• Fruiting bodies, like mushrooms, produce spores for reproduction.
• Ascomycota produce asci, containing sexual ascospores, while Basidiomycota produce basidia, bearing sexual basidiospores.
• Examples of Basidiomycota include edible mushrooms (Agaricus) and deadly species like Amanita (containing the toxin Amanitin).

This lecture focuses on the general features of fungi, belonging to the domain Eukarya and kingdom Fungi. It's a continuation of the previous lecture on Protists.