Structure and Function of Fungi

Basic Structure and Function of Fungi

• Fungi include various organisms like molds, yeasts, mildews, rusts, toadstools, and mushrooms.
• They are categorized as macroscopic (e.g., mushrooms) or microscopic (e.g., bread molds).
• Fungi are eukaryotes, possessing a true nucleus.
• Most fungi are saprophytes, feeding on dead organic matter. Some are parasitic, living on living organisms.

Structure of Fungi

• Fungi, like Rhizopus, are typically multicellular, composed of branched filaments called hyphae.
• Hyphae lack cross-walls and contain cytoplasm and multiple nuclei. A single hypha is a coenocyte.
• Hyphae are categorized as:
  • Runners (stolons): branch horizontally on substrates.
  • Rhizoids: penetrate the substrate, anchoring the mycelium.
  • Sporangiophores: grow vertically, forming sporangia that produce spores.
• The interwoven network of hyphae is called a mycelium.
• Spores are reproductive structures found at the tips of hyphae.
• Fungi lacking true roots, stems, or leaves are called thallus.
• Fungi cell walls can contain chitin or cellulose. Chitin is harder and contains nitrogen.

Function and Characteristics of Fungi

• Some fungi are unicellular (e.g., yeasts, molds), others multicellular (e.g., mushrooms).
• Fungi lack chlorophyll and are heterotrophic, meaning they don't photosynthesize.
• Fungi can be saprotrophic (feeding on dead matter) or parasitic (feeding on living organisms).
• To digest matter, saprotrophic fungi secrete enzymes, absorbing the resulting nutrients.
• Fungi can cause diseases such as thrush, ringworm, and athlete's foot.
• Fungi store carbohydrates as glycogen.
• Fungi are crucial for nutrient recycling in soil and atmosphere.
• Fungi reproduce both sexually and asexually.
• Unicellular fungi reproduce asexually by binary fission or budding.
• Multicellular fungi reproduce asexually by spores when conditions are unfavorable, and sexually under favorable conditions.