Kingdom Fungi

Fungi are a unique kingdom of heterotrophic organisms with incredible diversity! You’ve seen them on moldy bread 🍞, rotten fruit 🍓, mushrooms 🍄, and even as white spots on mustard leaves. They’re everywhere—air, soil, water, plants, and animals—and love warm, humid places.

Key Features:

  • Structure: Mostly filamentous (except unicellular yeast). Their body is made of thread-like hyphae. A network of hyphae forms the mycelium.
  • Cell Walls: Made of chitin and polysaccharides.
  • Nutrition:
    • 🍂 Saprophytes: Absorb food from dead matter.
    • 🦠 Parasites: Live on living hosts (e.g., wheat rust fungus).
    • 🤝 Symbionts: Partner with algae (as lichens) or plant roots (as mycorrhiza).

Reproduction:

  • Vegetative: Fragmentation, fission, budding.
  • Asexual: Via spores like conidia, sporangiospores, or zoospores.
  • Sexual: Involves 3 steps:
    1. Plasmogamy: Fusion of two gametes’ cytoplasm.
    2. Karyogamy: Fusion of their nuclei.
    3. Meiosis: Zygote divides to form haploid spores (oospores, ascospores, basidiospores).
    Some fungi (e.g., ascomycetes) have a dikaryotic stage (n + n) before becoming diploid.

Classification of Fungi:

1. Phycomycetes 🌊

  • Found in water, moist wood, or as plant parasites.
  • Mycelium: Aseptate and coenocytic (multinucleated).
  • Asexual spores: Zoospores (motile) or aplanospores (non-motile).
  • Sexual spores: Zygospores (from fused gametes).
  • Examples: Mucor, Rhizopus (bread mold), Albugo (mustard parasite).

2. Ascomycetes (Sac Fungi) 🧴

  • Mostly multicellular (e.g., Penicillium), some unicellular (e.g., yeast).
  • Mycelium: Branched and septate.
  • Asexual spores: Conidia (on conidiophores).
  • Sexual spores: Ascospores (in sac-like asci within ascocarps).
  • Examples: Aspergillus, Claviceps, Neurospora. Edible ones: morels, truffles 🍄.

3. Basidiomycetes (Club Fungi) 🍄

  • Include mushrooms, puffballs, and plant parasites (e.g., rusts).
  • Mycelium: Branched and septate.
  • No asexual spores; reproduces via fragmentation.
  • Sexual spores: Basidiospores (on club-shaped basidia in basidiocarps).
  • Examples: Agaricus (mushroom), Ustilago (smut), Puccinia (rust fungus).

4. Deuteromycetes (Imperfect Fungi) ❓

  • Only asexual stage known; sexual stage undiscovered or classified elsewhere.
  • Reproduce via conidia.
  • Mycelium: Septate and branched.
  • Examples: Alternaria, Colletotrichum, Trichoderma.

Kingdom Plantae 🌿

  • Eukaryotic, chlorophyll-containing organisms (mostly autotrophic).
  • Some heterotrophs: insectivorous plants (e.g., Venus flytrap) or parasites (e.g., Cuscuta).
  • Cell walls made of cellulose.
  • Exhibit alternation of generations (diploid sporophyte + haploid gametophyte).

Kingdom Animalia 🐾

  • Heterotrophic, multicellular eukaryotes without cell walls.
  • Digest food internally; store energy as glycogen or fat.
  • Nutrition: Holozoic (ingest food).
  • Most can move; complex sensory systems.
  • Reproduction: Sexual via copulation + embryonic development.

Viruses, Viroids, Prions & Lichens 🦠

  • Viruses: Non-cellular, inert crystalline structures. Cause diseases (e.g., common cold). Not considered “alive” due to lack of cellular structure.
  • Lichens: Symbiotic associations (fungi + algae).

Important Concepts for NEET 🎯

  1. Fungal Reproduction Steps: Plasmogamy → Karyogamy → Meiosis. Dikaryotic stage in ascomycetes/basidiomycetes.
  2. Fungal Classes & Examples:
    • Phycomycetes: Mucor, Rhizopus
    • Ascomycetes: Penicillium (antibiotics), yeast
    • Basidiomycetes: Mushrooms, rust/smut fungi
  3. Symbiotic Associations: Lichens (fungi + algae) and mycorrhiza (fungi + plant roots).
  4. Viruses: Non-cellular, cause diseases (e.g., flu), inert outside host cells.
  5. Kingdom Key Features:
    • Plantae: Cellulose walls, autotrophic.
    • Animalia: No cell walls, holozoic nutrition.

Keep revising — you’re doing great! 💪