In order to make sense of the world, scientists consider similar characteristics and then group organisms according to those characteristics. At the time of publication, all known organisms have been placed into five kingdoms. These kingdoms include the plant, animal, protist, bacteria and fungi kingdoms. The organisms in the Fungi kingdom share many common characteristics.
On the cellular level, plants and fungi have some similarities. Both plants and fungi have cell walls. However, the cell walls of plants contain cellulose. Fungi cell walls do not contain cellulose, but contain chitin. Both types of cells have the same cytoplasmic structure, but they have different organelles within the cytoplasm. Additionally, fungi store their food energy in the form of glycogen like animal cells instead of in the form of starch as plants do. Fungi also are different because they have "small nuclei with very little repetitive DNA," according to Biology Online.
Most fungi contain stalk-like structures called hyphae. These hyphae then grow in a mass, like a twisted ball of string or the underground roots of plants. This mass of interconnected hyphae is called a mycelium. The exception to this structure is found in yeast, which has a unicellular structure.
Fungi are heterotrophs, which means they feed on other organisms. They do not contain chloroplasts or chlorophyll, which are the essential structures plants use to make their own food. Although they feed on other organisms, like animals, their method is different. Animals take in their food and then digest it internally. Fungi release enzymes into the environment which digest the material, and then they absorb it. Some fungi feed on decaying organic matter while some are parasites and still others are found in mutualistic relationships with other organisms.
Fungi usually reproduce with spores. These spores can be asexual or sexual, depending on the type of organism. Spores can also be used as a dormant, or resting stage. Fungi can also reproduce through budding or fragmentation.