Fungi Cheatsheet

Cheatsheet Content

Fungi Characteristics Eukaryotic: Possess a true nucleus and membrane-bound organelles. Heterotrophic: Obtain nutrients by absorption (secrete enzymes externally). Cell Walls: Primarily composed of chitin (a polysaccharide), unlike plant cellulose. Body Structure: Most are multicellular (e.g., molds, mushrooms) with hyphae forming a mycelium; some are unicellular (e.g., yeasts). Non-motile: Generally lack flagella (except some aquatic forms/spores). Storage: Store carbohydrates as glycogen, similar to animals. Fungi Classification (Major Phyla) Chytridiomycota (Chytrids): Simplest fungi, often aquatic. Possess flagellated spores (zoospores). Some are parasites, others decomposers. Zygomycota (Bread Molds): Characterized by zygosporangia (sexual spores). Aseptate hyphae (lacking cross-walls). Examples: Rhizopus (black bread mold). Ascomycota (Sac Fungi): Produce sexual spores (ascospores) in a sac-like structure called an ascus. Diverse group: yeasts, truffles, morels, powdery mildews. Many form symbiotic relationships (lichens). Basidiomycota (Club Fungi): Produce sexual spores (basidiospores) on a club-shaped structure called a basidium. Includes mushrooms, puffballs, bracket fungi, rusts, and smuts. Important decomposers and mycorrhizal partners. Glomeromycota: Form arbuscular mycorrhizae (AM fungi) with plant roots. Obligate symbionts, crucial for nutrient uptake in plants. Reproduce asexually. Fungi Reproduction Asexual Reproduction: Budding: (e.g., yeasts) A small outgrowth detaches and grows into a new organism. Fragmentation: Mycelial fragments break off and establish new colonies. Spore Formation: Conidia: Asexually produced spores formed externally on hyphae. Sporangiospores: Asexually produced spores formed internally within a sporangium. Sexual Reproduction: Involves fusion of nuclei from two parent strains. Typically involves three stages: Plasmogamy: Fusion of cytoplasm from two parent mycelia. Karyogamy: Fusion of two haploid nuclei to form a diploid zygote nucleus. Meiosis: Production of haploid spores from the diploid zygote. Spore types vary by phylum (e.g., ascospores, basidiospores, zygospores). Economical Importance of Fungi Benefits: Decomposers: Break down organic matter, recycling nutrients in ecosystems. Food Source: Mushrooms (e.g., button, oyster, shiitake), truffles, morels. Food Production: Yeast ( Saccharomyces cerevisiae ): Bread baking (leavening), beer brewing (fermentation), wine making. Cheese Production: Blue cheese ( Penicillium roqueforti ), Camembert ( Penicillium camemberti ). Medicine: Antibiotics: Penicillin from Penicillium chrysogenum . Immunosuppressants: Cyclosporine from Tolypocladium inflatum (prevents organ rejection). Statins: Lovastatin from Aspergillus terreus (cholesterol-lowering). Bioremediation: Degrade pollutants (e.g., oil spills, pesticides). Mycorrhizal Associations: Enhance nutrient (especially phosphorus) uptake for plants. Biocontrol Agents: Used to control insect pests or plant diseases. Harmful Aspects: Plant Diseases: Rusts and Smuts (Basidiomycota): Affect cereal crops. Powdery Mildew (Ascomycota): Affects various plants. Dutch Elm Disease, Chestnut Blight. Crop spoilage and post-harvest losses. Animal and Human Diseases (Mycoses): Superficial: Athlete's foot, ringworm (dermatophytes). Cutaneous: Affect skin, hair, nails. Subcutaneous: Enter through skin wounds (e.g., sporotrichosis). Systemic: Affect internal organs, often severe in immunocompromised individuals (e.g., candidiasis, aspergillosis, histoplasmosis). Toxins (Mycotoxins): Aflatoxins: Produced by Aspergillus flavus , contaminate grains/nuts, highly carcinogenic. Ergot alkaloids: Produced by Claviceps purpurea on rye, causes ergotism. Food Spoilage: Molds can spoil food, making it inedible or toxic. Structural Damage: Wood rot in buildings, dry rot.