NOTES l Kingdom Fungi - Class 11 and NEET 2025/2026

 

Overview

The Kingdom Fungi is comprised of unique heterotrophic organisms with a diverse range of morphologies and habitats Fungi can be found on moist bread, rotten fruits, and even on leaves as parasitic white spots Common fungi include mushrooms, toadstools, yeast (used in bread and beer making), and Penicillium (source of antibiotics) Fungi are cosmopolitan, occurring in air, water, soil, and on animals and plants, often thriving in warm and humid environments

Key Characteristics:

• Unicellular and Filamentous Forms: Except for unicellular yeasts, fungi are filamentous, consisting of hyphae (long, slender threads) The network of hyphae forms the mycelium
• Cell Wall Composition: Fungal cell walls are composed of chitin and polysaccharides
• Modes of Nutrition: Fungi can be saprophytic (absorbing nutrients from dead organic matter), parasitic (living on living plants and animals), or symbiotic (eg, lichens and mycorrhiza)

Reproduction:

• Vegetative Reproduction: Occurs through fragmentation, fission, and budding
• Asexual Reproduction: Involves spores like conidia, sporangiospores, and zoospores
• Sexual Reproduction: Involves oospores, ascospores, and basidiospores, produced in fruiting bodies The sexual cycle includes plasmogamy (fusion of protoplasms), karyogamy (fusion of nuclei), and meiosis resulting in haploid spores

Classification of Fungi:

1 Phycomycetes

• Habitat: Aquatic environments, moist and damp places, or as parasites on plants
• Characteristics: Aseptate and coenocytic mycelium
• Reproduction: Asexual spores (zoospores or aplanospores) produced in sporangium Sexual reproduction through gamete fusion forming zygospores
• Examples: Mucor, Rhizopus (bread mold), Albugo (parasitic on mustard)

2 Ascomycetes (Sac Fungi)

• Habitat: Multicellular (eg, Penicillium) or unicellular (eg, yeast)
• Characteristics: Saprophytic, decomposers, parasitic, or coprophilous Branched and septate mycelium
• Reproduction: Asexual spores (conidia) produced on conidiophores Sexual spores (ascospores) produced in asci, arranged in ascocarps
• Examples: Aspergillus, Claviceps, Neurospora (used in genetic studies), morels, and truffles (edible delicacies)

3 Basidiomycetes

• Habitat: Soil, logs, tree stumps, and living plant bodies (as parasites)
• Characteristics: Branched and septate mycelium Vegetative reproduction by fragmentation
• Reproduction: Sexual reproduction through basidia, producing basidiospores exogenously Basidia arranged in basidiocarps
• Examples: Agaricus (mushroom), Ustilago (smut), Puccinia (rust fungus)

4 Deuteromycetes (Imperfect Fungi)

• Characteristics: Known for only asexual or vegetative stages Septate and branched mycelium
• Reproduction: Asexual spores (conidia)
• Role: Saprophytes, parasites, decomposers aiding in mineral cycling
• Examples: Alternaria, Colletotrichum, Trichoderma

Also Read:

• Virus, Viroids and Prions - NOTES
• NOTES: Class 11
• MCQs: Class 11
• Tips for NEET