Fungi
Fungi Basics
•
•
•
•
Fungi 1
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.
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.
•
•
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.
Yeast cells
How They Get Around
•
•
•
Fungi 2
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
Where They’re Found
•
•
Fungi 3
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 Extras
Read 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 nutrients
Fungi 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