Kingdom Classification - Fungi

Characteristics

• Eukaryotic: Possess a true nucleus and membrane-bound organelles.
• Heterotrophic: Obtain nutrients by absorbing dissolved organic molecules from their environment (saprophytic or parasitic).
• Cell Wall: Have cell walls made of chitin.
• Reproduction: Reproduce by spores, budding, or fragmentation.
• Structure: Most are multicellular, composed of filamentous structures called hyphae, which collectively form a mycelium. Yeasts are unicellular fungi.

Major Phyla of Fungi

The kingdom Fungi is comprised of five major phyla, which are distinguished by their mode of sexual reproduction and molecular data.

• Chytridiomycota (Chytrids):
  • Characteristics: The most primitive group of fungi. Produce motile spores (zoospores) with a single flagellum. Most are unicellular and aquatic.
• Zygomycota (Conjugated Fungi):
  • Characteristics: Includes common molds. Form a thick-walled zygospore during sexual reproduction. Have coenocytic hyphae (lack septa).
• Ascomycota (Sac Fungi):
  • Characteristics: The largest phylum of fungi. Produce sexual spores in a sac-like structure called an ascus. Includes yeasts, morels, truffles, and powdery mildews.
• Basidiomycota (Club Fungi):
  • Characteristics: Includes mushrooms, puffballs, and rusts. Produce sexual spores on a club-shaped structure called a basidium.
• Glomeromycota:
  • Characteristics: Form arbuscular mycorrhizae with the roots of plants. Reproduce asexually.

Basic Structure of Mould

Moulds are a type of multicellular fungi.

• Hyphae: Thread-like structures that make up the body of a fungus. They grow and branch out, forming a network.
• Mycelium: The entire mass of hyphae that forms the vegetative part of a fungus.
• Sporangiophores: Specialized hyphae that bear sporangia.
• Sporangium: A sac-like structure that contains spores.
• Spores: Reproductive units that can germinate to form new hyphae.

Nutrition in Mould

Moulds are heterotrophic and primarily saprophytic, meaning they obtain nutrients from dead or decaying organic matter. They secrete digestive enzymes onto their food source, breaking down complex organic molecules into simpler ones, which are then absorbed through their cell walls.

Respiration in Mould

Moulds can perform both aerobic and anaerobic respiration.

• Aerobic Respiration: Occurs in the presence of oxygen, breaking down glucose completely to produce carbon dioxide, water, and a large amount of energy.
• Anaerobic Respiration (Fermentation): Occurs in the absence of oxygen, breaking down glucose incompletely to produce alcohol (in yeast) or other organic acids, carbon dioxide, and a small amount of energy.

Useful Fungi (Applications related to daily life)

• Food Production:
  • Yeast (Saccharomyces cerevisiae): Used in baking (bread making) for fermentation, producing carbon dioxide that makes dough rise. Also used in brewing (beer, wine) for alcohol production.
  • Mushrooms: Many species are edible and consumed as food (e.g., button mushrooms, oyster mushrooms).
  • Cheese Production: Specific fungi (e.g., Penicillium roqueforti, Penicillium camemberti) are used to ripen and give characteristic flavors to cheeses like Roquefort and Camembert.
• Medicine:
  • Antibiotics: Penicillin, a life-saving antibiotic, is derived from the fungus Penicillium chrysogenum.
  • Immunosuppressants: Cyclosporine, used to prevent organ transplant rejection, is derived from a fungus.
• Decomposition: Fungi are crucial decomposers in ecosystems, breaking down dead organic matter and recycling nutrients.

Harmful Fungi (Applications related to daily life)

• Diseases:
  • In Plants: Cause various plant diseases, leading to crop loss (e.g., rusts, smuts, blights).
  • In Humans: Cause skin infections (e.g., ringworm, athlete's foot), candidiasis (yeast infections), and respiratory infections (e.g., aspergillosis).
• Food Spoilage: Cause spoilage of food items like bread, fruits, and vegetables, leading to economic losses and potential health risks (e.g., aflatoxins produced by Aspergillus).
• Damage to Materials: Can grow on and damage wood, textiles, and other materials, especially in damp conditions.