Yeast helps bread rise and beer ferment. Living off others Fly agaric is deadly. Eating even small amounts can knock you out. Although they grow in the ground like plants, fungi are not really plants because they have no chlorophyll and so cannot make their own food. Because they cannot make their own food, fungi must live off other plants and animals.
Fungi are the biodegraders of the living world.
Both feed by releasing special chemicals called enzymes which rot away whatever they are feeding on. The fungi absorb the nutrients and minerals from the rotting organism. The chemicals released by some mould fungi give blue cheeses their flavour, others can make mouldy bread deadly. What fungi are made of Fungi are made of hundreds of cotton-like threads called hyphae, which can digest and absorb the materials they live on. Hyphae usually spread out in a tangled mass through the soil - or within the tissues of the plant or animal they are living on.