Year 1 · Classification · Section 3.5

Fungi

Structure

Fungi have cells with a nucleus and a cell wall, but no chloroplasts. They cannot carry out photosynthesis. Fungi can be unicellular or multicellular:

• Unicellular fungi: Include yeasts, many of which reproduce by budding.
• Multicellular fungi: Usually consist of long threads called hyphae, which you can see on mouldy bread.

Reproduction

Yeasts commonly reproduce by a form of cell division called budding. A small outgrowth develops into a new cell.

Multicellular fungi often reproduce using spores. These may form on specialised hyphae or in fruiting bodies such as mushrooms. Fly agarics and button mushrooms are examples. A mushroom is a reproductive structure; some, such as button mushrooms, are edible.

Benefits and harm

Fungi play important roles in nature and human life:

• They break down dead plant and animal material, acting as decomposers.
• They can spoil food and cause diseases such as athlete's foot.
• Fungal infections can be treated with appropriate antifungal medicines.

Biotechnology

Biotechnology uses organisms or parts of them to make useful products. Fungi are used to produce food and drink:

• In bread-making, yeast produces carbon dioxide, making dough rise.
• In beer and wine-making, yeast produces alcohol.
• Certain fungi are used to make mould-ripened cheeses.

Fungi also produce medicines. Penicillin, originally obtained from a Penicillium mould, is an antibiotic that acts against susceptible bacteria.