Definition of Fungi
Fungi are a kingdom of eukaryotic organisms that includes microorganisms like yeasts and molds, as well as more familiar mushrooms. They are distinct from plants and animals, primarily characterized by a cell wall made of chitin and a heterotrophic mode of nutrition, meaning they absorb nutrients from their environment.
Key Characteristics and Structure
Unlike plants, fungi do not perform photosynthesis; instead, they digest food externally by secreting enzymes and then absorbing the broken-down molecules. Most fungi grow as microscopic filaments called hyphae, which form a network called a mycelium. Some, like yeasts, are single-celled. Their rigid cell walls provide structural support.
Practical Examples and Roles
Fungi play vital roles across various environments. Examples include edible mushrooms, yeast used in baking and brewing, and penicillin, a life-saving antibiotic derived from mold. In nature, fungi are crucial decomposers, breaking down dead organic matter and recycling nutrients back into the soil, sustaining plant growth.
Importance in Ecosystems and Human Life
Beyond decomposition, fungi form symbiotic relationships, such as mycorrhizae with plant roots, enhancing nutrient uptake, and lichens, a partnership with algae or cyanobacteria. They are also a significant source of food, medicines, and industrial products, though some can cause diseases in plants and animals, including humans.