Fungi cells are the eukaryotic cells of organisms belonging to the Fungi kingdom. Although they share several features with plant and animal cells, there are some key structural differences that set the fungi cell apart from other types of eukaryotes.
What is a Fungi Cell?
For a long time, fungi were thought to be plant-like organisms, given their tendency to grow in soil and rigid cell walls. However, fungi cells lack chlorophyll, a green pigment required for photosynthesis that is almost ubiquitous among plants. In the late 1990s, scientists discovered that fungi actually diverged from animals around 9 million years later than plants did, making them more closely related to animals than plants.
Structure of a Fungi Cell
Fungi cells are eukaryotic so, like plant and animal cells, they contain membrane-bound organelles. However, there are some key structural differences between fungi cells and other types of eukaryotic cells.
Like all eukaryotes, fungi cells contain membrane-bound organelles including a nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus. They also contain cytoplasm and ribosomes and are surrounded by a plasma membrane.
Like plant cells, fungal cells are surrounded by a rigid cell wall that protects and supports the cell. However, the primary structural material in the fungal cell wall is chitin, a complex polysaccharide that is also found in the exoskeleton of insects. This is different from the plant cell wall, which contains cellulose.
A few types of fungi cells contain plasmids. These are small loops of DNA comparable to those found in bacterial cells.
Fungi produce a variety of pigments, which give these organisms their wide range of vibrant colors. These pigments also protect the fungi against UV radiation and oxidative stress. Some fungal pigments are toxic to humans, but others have useful applications in a variety of industries.
Types of Fungi Cells
The two major types of fungi cells are yeast cells (unicellular fungi) and hyphae cells (the individual cells of multicellular, filamentous fungi).
Hyphae are branching, threadlike structures found in multicellular, filamentous fungi. A single hypha consists of a long chain of tubular hyphae cells, which are joined together and divided by internal walls called septa. Hyphae grow from their tips, which allows the filaments to spread and branch out into new substrates. The hyphae release digestive enzymes into the substrate, which break it down into nutrients that the fungus can absorb.
Hyphae reproduce asexually using a process called fragmentation. During fragmentation, small pieces of hyphae can break off and grow to form a new colony of fungal cells.
Yeasts are unicellular fungi that reproduce asexually by budding. During this process, the yeast cell nucleus divides by mitosis, and a bud forms on the surface of the cell. Eventually, the bud will detach to become a new, genetically identical daughter cell.
Budding produces pseudohyphae; elongated, newly-formed cells that resemble hyphae. Unlike true hyphae, pseudohyphae are made of conjoined but individual yeast cells that are easily separated from one another. The cells of true hyphae are parts of a multicellular organism and are fused together by septa.
Fungi Cell Reproduction
Unlike most eukaryotic organisms, fungi usually reproduce asexually. They do this either by budding, through fragmentation, or by producing spores. The production of spores is the most common form of asexual reproduction in fungi. Spores are produced by mitosis and are genetically identical to the parent organism. They are then released in large numbers and disperse long distances on the wind, before settling and growing into a new, genetically identical fungus.
Fungi Cells vs. Plant and Animal Cells
|Polysaccharide found in cell wall||Chitin||Cellulose||N/A|