NutritionOrganisms are classified as fungi based largely on their mode of obtaining nutrition. Fungi are heterotrophs and need to obtain organic compounds from other organisms. Many fungi are classified as saprobes, feeding on dead organisms, thus facilitating their decay. Others obtain nutrition as parasites, feeding off of living tissue.
As fungi grow on organic material, they secrete digestive enzymes which break down proteins and other components outside the fungal cell. The fungi then absorb these digested products. This process is known as extracellular digestion.