Fungi play an important role in food production. Yeast, a type of fungus, is used to make bread and alcoholic beverages. Other fungi are used to produce cheeses and soy sauce. Fungi have rigid cell walls and feed by absorbing nutrients from dead or living matter. They reproduce both sexually through spores and asexually through hyphae and spores. Major groups of fungi include molds, yeasts, mushrooms, and lichens, which is a symbiotic combination of algae and fungi.

1. Fungi

2. How are
cheese, bread,
and soy sauce
related to
fungi?
A fungus can
help make
each of these
foods!

3. Fungi (singular form is fungus)
are everywhere
Mushrooms on pizza are a type
of fungus
Yeast used to make bread is a
fungus

4. If you’ve ever had athlete’s foot,
you can thank a fungus for that,
too!

5. Characteristics of Fungi
Fungi: eukaryotic heterotrophs that
have rigid cell walls and no
chlorophyll
Food for Fungi
– Cannot catch or surround food
– Must live on or near food supply
– Most are consumers—get nutrients by
secreting digestive juices onto a food
source and then absorbing dissolved
food

6. – Many are decomposers—
feed on dead plant or
animal matter
– Some fungi live in
mutualism with other
organisms
Example: many types of
fungi grow on or in roots
of plants and help the
roots absorb minerals
while the plant provides
nutrients to the fungus
This relationship between
a plant and a fungus is
called a mycorrihiza

7. Hidden From View
– Many-celled fungi are made
up of chains of cells called
hyphae
– Hyphae: threadlike fungal
filaments that are made up
of cells that have openings
in their cell walls
These openings allow
cytoplasm to move freely
between the cells
– Most of the hyphae that
make up a fungus grow
together to form a twisted
mass called the mycelium

9. Making More Fungi
– Reproduction is asexual or sexual
– ASEXUAL: occurs in 2 ways: (1) hyphae
break apart and each new piece makes a
new fungus or (2) spores spread by wind
and grow where they land
– SEXUAL: special structures
form sex cells and join
to produce sexual spores
that grow into a new
fungus

10. This puffball is releasing
sexual spores that can
produce new fungi.

11. Kinds of Fungi
Fungi classified based on
shape and the way that
they reproduce
Four main groups of
fungi:
– (1) threadlike fungi
– (2) sac fungi
– (3) club fungi
– (4) imperfect fungi

12. Threadlike Fungi
– Mold: a fungus that looks like wool or
cotton
– Most of these fungi live in the soil and
are decomposers
– Some are parasites
– Reproduce asexually—hyphae grow into
the air and form round spore cases
(sporangia), which break open and
release spores into air

13. YEAST
Sac Fungi
– Largest group of fungi
– Includes yeast, powdery
mildews, truffles, and
morels
– Reproduce sexually and
asexually during their life
cycles (when sexually, they
form sac called ascus)
MORELS

14. Side Note on Truffles
Truffles are difficult to find
and very expensive as a
result! In 1994, black
truffles sold for $350 to
$500 a pound. In the United
States, edible truffles are
collected in the forests of
Oregon and Washington. In
Europe, most truffles are
collected in France and Italy.
Truffle hunters in Italy and
France use pigs and mixed-
breed dogs to sniff out
truffles. Dogs are preferred
to pigs because pigs love to
eat truffles. Notice the staff
held by the truffle hunter in
the picture with the pig. The
hunter uses the staff to
force the pig to back off,
once the pig has located a
truffle

15. -Yeast are single celled and reproduce
by budding

16. –yeast used to make bread
and alcohol yeasts use
sugar as food and produce
carbon dioxide gas and
alcohol as waste. Trapped
bubbles of CO2 cause
bread dough to rise.
– Useful to humans
– Other sac fungi are
sources of antibiotics
and vitamins

17. Club Fungi
– Umbrella-shaped and
most familiar
– Example: mushrooms
– Reproduce sexually—
special hyphae grow
clublike structures
called basidia, where
spores develop
– In gill fungi, the
basidia of these
mushrooms develop
into structures called
gills, under the
mushroom cap

18. – Mushrooms usually
grow at the edges
of the mass of
hyphae
underground—this
is why mushrooms
often appear in
circles
– A ring of
mushrooms can
appear overnight.
In European folk
legends, these
were known as
“fairy rings”

19. BRACKET FUNGI
Nonmushroom Fungi
– Mushrooms are not the
only club fungi
– Also includes: bracket
fungi, puffballs, smuts,
and rusts
– Smuts and rusts are
common plant
parasites
CORN SMUT

20. Imperfect Fungi
– Includes all of the species of fungi that
do not quite fit into other groups
– Do not reproduce sexually
– Most are parasites that cause diseases
in plants and animals
– Example: athlete’s foot (a skin
disease)

21. – Some are useful
penicillum, which is
the source of
antibiotic penicillin

22. Lichens
– Combinations of a fungus and an alga
that grow together
– Alga actually lives inside the protective
walls of the fungus
– Result of mutualistic relationship
BRITISH SOLDIER LICHEN
CHRISTMAS LICHEN

23. –Unlike fungi, lichens are
producers—algae in lichen
produce food through
photosynthesis
–Because lichens need only light,
air, and minerals to grow, they
can grow on rocks
–Lichens make acids that break
down rocks and cause cracks
–Lichens absorb water and
minerals from air easily
affected by air pollution