Fungi

Fungi 1Fungi Basics

• Yeasts are single-celled fungi, so they are microbes. So is mold.

• Fungi are usually bigger than bacteria.• If there is just one of them, we call it a

fungus. • Fungi are more like animals than

plants. For one thing, fungi cannot make their own food like plants do, but instead they eat other organisms, as animals do.

• With fungi, there are good guys and there are bad guys. Some make our food go moldy, and some cause diseases. But they also break down dead plants and animals, keeping the world tidier.

• We use some fungi to do things for us, like make bread rise and brew beer.

These mushrooms are fungi, but they’re big and they’ve got loads of cells, so they’re not microbes. We’ll ignore these for now.

Yeast cells

Fungi 2How They Get Around• Individual fungi don’t move around. • But they can spread by making tiny

spores (a bit like seeds) that are carried by wind and rain and grow into new fungus cells when they land.

• Some fungi, such as molds, make long threads of cells called hyphae. These threads are what make mold look fuzzy. Molds can spread by growing and extending their hyphae.

What They Look Like• Fungi come in a variety of shapes and

sizes and different types. They can range from single cells to enormous chains of cells that can stretch for miles.

• Yeast cells look round or oval under a microscope. They're bigger than bacteria, but still too small for your eyes to see them individually.

Draw and label this fungus cell

Fungi 3Where They’re Found• Fungi usually grow best in places that are

slightly acidic. Fungi live in the soil and on your body, in your house and on plants and animals, in freshwater and seawater.

• A single teaspoon of soil contains about 120,000 fungus cells!

Whoa! The mould on this bread is really out of control!

• If you ever get athlete’s foot (a skin complaint that gives you itchy feet), then you’ve got a fungus growing on you! (Don’t worry, it’s not serious, and you can buy an ointment that kills the fungus.) The fungus likes moisture, so drying between your toes helps to keep it away.

Fungi ExtrasRead at your own risk – this may shock you!

The Humongous Fungus (definitely not a microbe!)

• Fungi range in size from the microbe we call yeast to the largest known living organism on Earth — a 3.5-mile-wide fungus.

• Nicknamed ‘the humongous fungus’, this honey mushroom covers 2,200 acres in the state of Oregon, in the USA.

• The only above-ground signs of the humongous fungus are patches of dead trees (which the fungus has killed by eating them), and the mushrooms (the ‘fruits’ of the fungus) that form at the base of infected trees.

• It started out 2,400 years ago as a single spore invisible to the naked eye. It slowly grew to immense size by growing long threads of cells called hyphae, under the ground.

Threads called hyphae grow and

spread underground

Fungal Characteristics•Fungi are non-vascular: they have no internal pipes to distribute nutrientsFungi have a cell wall, like plants do, but it is composed of chitin, the same material that covers insects•Fungi reproduce by means of spores, which can be sexual (the products of meiosis) or asexual (the products of mitosis). Each group of fungi has a unique set of spores. Asexual reproduction is more common than sexual•Recent DNA-based studies show that fungi are more similar to animals than to plants

Club Fungi

• Mushrooms are the most common club fungi. Others include rusts and smuts that harm crop plants.

• The visible mushroom is merely a fruiting body. The bulk of the organism is underground, a mat of hyphae (strands) called a mycellium that can be quite large.

Zygomycetes• Bread mold is a common

zygomycete.• Another important zygomycete

group is the mycchorrhyzae, fungi that infect the roots of most plants. These fungi have a symbiotic relationship with the plants: the fungi gather nutrients form the soil as an extension of the roots, and the plant supplies nutrients from photosynthesis

Ascomycetes• Ascomycetes are sac fungi:

they produce spores in sacs.• Truffles and morels are good

examples of ascomycetes: they taste good!

• Penicillium, the mold that gave penicillin, the first antibiotic, is an ascomycete. Pennicillium also gives flavor to certain cheeses.

• Sac fungi also include some important single celled yeasts. Saccharomyces cerevesiae is used to make bread rise and also to ferment beer and wine. Candida albicans produces the common human yeast infections