Final answer:
Fungi predominantly consist of hyphae, which are thread-like filaments that make up their structural framework. Hyphae can be septate, with septa dividing the filaments into cells, or coenocytic, forming large multinucleated cells. These filaments intertwine to form a mycelium, the main body of a fungus.
Step-by-step explanation:
Most fungi grow in a form consisting of thread-like filaments known as hyphae (singular, hypha). A hypha is composed of one or more cells surrounded by a tubular cell wall. There are two types of hyphae based on their internal structure: septate hyphae, which are divided into separate cells by end walls called septa (singular, septum), and coenocytic hyphae, which lack septa and contain many nuclei within a single, elongated cell.
Septa in septate hyphae usually have pores that allow for the flow of organelles and nutrients between cells, facilitating rapid transport within the fungus. In contrast, coenocytic hyphae, such as those found in the division Zygomycota (e.g., bread molds), are large cells that are multinucleated, since they lack internal walls dividing the filament into separate cells.
The interconnected network of hyphae forms a structure called a mycelium. This mycelial structure can be an extensive, anastomosing mass of hyphal filaments that allows fungi to efficiently absorb nutrients from their environment.
The process of fungal reproduction often involves the formation of specialized hyphae. For instance, in the club fungi group Basidiomycota, basidia are formed on gills and produce spores.