Pg:- 18,19,20

Fungi are a kingdom of eukaryotic organisms that include yeasts, molds, and mushrooms.

Characteristics of Fungi:

1. Eukaryotic Cells:

   • Fungi have complex cells with a defined nucleus and membrane-bound organelles, similar to other eukaryotes.

2. Cell Walls:

   • Fungal cell walls are primarily composed of chitin, a strong and flexible polysaccharide. This differs from plant cell walls, which are made of cellulose.

3. Heterotrophic Nutrition:

   • Fungi are heterotrophs, meaning they cannot produce their own food through photosynthesis. Instead, they absorb nutrients from their surroundings.

   • They secrete enzymes that break down complex organic material into simpler compounds that can be absorbed.

4. Reproduction:

   • Fungi can reproduce both sexually and asexually.

   • Asexual reproduction often involves spore formation, budding, or fragmentation.

   • Sexual reproduction involves the fusion of hyphae (filamentous structures) from two different fungal individuals to form a new organism.

5. Hyphal Structure:

   • The body of most fungi is composed of a network of hyphae, which form a mycelium. This structure allows for efficient nutrient absorption.

6. Ecological Roles:

   • Decomposers: Fungi play a crucial role in breaking down dead organic material, and recycling nutrients back into the ecosystem.

   • Symbionts: Many fungi form mutualistic relationships with plants (mycorrhizae) and animals.

   • Pathogens: Some fungi are pathogenic to plants, animals, and humans, causing diseases.

Facts:

• Diversity:

  • There are an estimated 2.2 to 3.8 million species of fungi, though only about 120,000 have been described by scientists.

• Mycorrhizae:

  • About 90% of plant species form symbiotic relationships with fungi. Mycorrhizal fungi enhance nutrient and water uptake for plants, while receiving carbohydrates in return.

• Largest Organism:

  • The largest organism on Earth is a fungus, Armillaria ostoyae, which covers over 2,385 acres (965 hectares) in Oregon's Malheur National Forest. This "humongous fungus" is estimated to be thousands of years old.

• Penicillin:

  • The antibiotic penicillin, discovered by Alexander Fleming in 1928, is derived from the fungus Penicillium notatum. This discovery revolutionized medicine by providing a powerful tool to fight bacterial infections.

• Lichens:

  • Lichens are symbiotic associations between fungi and algae or cyanobacteria. They can survive in extreme environments, from arctic tundra to deserts, and play important roles in soil formation and ecosystem stability.

• Bioluminescence:

  • Some fungi exhibit bioluminescence, emitting light through chemical reactions. Examples include the "foxfire" or "fairy fire" fungi found on decaying wood.

• Cordyceps:

  • Cordyceps fungi are known for their parasitic relationship with insects. They infect and eventually kill the host, growing their fruiting bodies out of the insect's body.

• Fungal Infections:

  • Fungi can cause diseases in humans, such as athlete's foot, and ringworm, and more serious infections like histoplasmosis and candidiasis.

• Fungi and Food:

  • Many fungi are essential in food production. Yeasts (Saccharomyces cerevisiae) are used in baking and brewing, while molds are used to produce cheeses like blue cheese and Camembert.

• Psychoactive Fungi:

  • Some fungi, like Psilocybe species, produce psychoactive compounds (e.g., psilocybin) that have been used in traditional spiritual practices and are being studied for their potential therapeutic effects.