Fungi are classified as a separate kingdom from plants and animals. They are made up of branching threads called hyphae. Yeasts differ from typical fungi in that they are single-celled. Penicillium and yeasts are classified as higher fungi, with Penicillium having septated hyphae and yeasts lacking hyphae. Penicillium produces useful enzymes and is used in the production of foods like cheese and antibiotics. Yeasts like Saccharomyces cerevisiae are single-celled and used in breadmaking.