What Makes a Fungus a Fungus
Fungus
Scientists used to classify fungi as plants. Like plants, fungi do not move
from place to place. They also have cell walls. Unlike plants, they do not have
chloroplasts, so they cannot make their own food. The three main kinds of
fungus that we will study are molds, mushrooms and yeast.
How Fungi Get Food
Fungi get their food from either dead things or living things. They release
chemicals called enzymes that digest the food that they are on or in. Then the
fungi absorb the smaller food particles.
Decomposition is when fungi break down dead things for food. The
wastes are then used over by other living things. In this way, all substances are
recycled in nature.
Structure of Fungi
Fungi have a structure unlike other living things. Most fungi are made of
branching threads called hyphae. Often, hyphae grow into a thick, twisted mat
called a mycelium. On a mushroom, the part of the mycelium that is above
ground is for reproduction and the part below ground is for feeding.
Yeasts are one kind of fungus that do not form hyphae. They are only made of
one cell. They are shaped like little bagels.
How Fungi Reproduce
Molds and mushrooms reproduce by spores which are tiny reproductive
cells that grow into new fungi. Yeasts do not have spores, but reproduce by
budding. A new cell called a bud grows out from the yeast cell. They
eventually separate from the original yeast cell making two yeast cells.
Harmful Fungi
Some diseases are caused by fungus. Athlete's foot is a fungi that eats
the dead skin on your foot. Fungus likes warm, dark, moist places and your foot
is perfect for that! Ringworm is a skin disease caused by fungus, not worms.
Yeasts also cause reproductive diseases, the infamous "yeast infection."
Some fungi cause diseases in crop plants. Corn smut is a fungus that
infects grains of corn on the ears. Wheat rust infects wheat plants. Potato
blight is a fungus that affected potatoes in Ireland in the 1800's and caused a
major famine.
Some fungi can make you sick or even cause death if eaten. The
amanita mushroom is very poisonous. Never eat wild mushrooms unless you
are sure of their identification.
Bread mold grows on bread and causes it to spoil. We will look at bread
mold in the lab.
Helpful Fungi
Some fungi, such as certain mushrooms, puffballs and morels are good
to eat. Raising them for food is an important business. They are often grown
in caves and mines since fungi grow best in dark places.
Many fungi decompose dead things, the recyclers in nature.
Yeast is used in fermentation to change sugar into alcohol. This makes
beer and wine. Yeast is also used in baking to raise bread dough. As the yeast
"eats" the sugar in the dough, it gives off carbon dioxide gas which causes the
bread to rise.
Molds can also be helpful. The antibiotic, penicillin, comes from mold
that grows on oranges. Penicillin kills bacteria and has saved millions of lives.
Molds are also used in products like soy sauce and blue cheese. The "blue" in
blue cheese is actually a mold that gives it a distinct flavor.
Cap
Stalk
Gills
Spores
Stalk
Hyphae (1 thread)
Feeding Mycelium
(Many threads packed together)
Cap
Stalk
Gills
Spores
Stalk
Hyphae (1 thread)
Feeding Mycelium
(Many threads packed together)