FUNGI

Fungi are simple organisms that are neither plant nor animal, yet have characteristics of both and absorb food from whatever organic source on which they are growing. Since they eat and absorb anything organic, fungi are decomposers. There are three common groups of fungi: Mold Mushrooms Yeast How do fungi compare in terms of size to bacteria and protists?

MOLD Have you ever seen mold? Mold is found in many places and grows under a variety of conditions where air and moisture are present. The mold we see with the naked eye is actually a colony of millions of mold cells growing together. Molds vary in appearance. Some are fluffy and filament-like, some are moist and glossy, and some are slimy. The mold absorbs food from the item on which it is growing to live and produce new cells. Molds reproduce through spores which are carried by air currents and deposited to start new mold colonies when conditions are right. Molds are helpful in producing foods. They add flavor and color to cheese and make soy sauce. They also make chemicals like citric and lactic acid and many enzymes. Molds are harmful in spoiling food. Since mold spores are abundant in the air, any food allowed to stand in the open soon becomes contaminates with mold. Some types of mold can also grow in cool temperatures, so mold can grow on foods in the refrigerator. Some molds produce poisons called mycotoxins.

MUSHROOMS Mushrooms are part of a group called Club fungi. Label the parts of a mushroom. The fruiting body of a mushroom that we see above ground is made of a cap with gills underneath and attached to a stalk. Under the group the “roots” of a mushroom are really mycelium, which grow in very fertile soil or other organic matter. The mycelium may slowly grow underground for years waiting for the right conditions under which to produce the fruiting body or mushroom. Mycelium is composed of hyphae. The spores are formed by the fills located under the cap. When time is right, the gills release the spores which are carried by air currents and deposited to start new growth. Mushrooms should never be eaten in the wild, since they may be poisonous. Club fungi also includes rusts and smuts. Rusts produce rust-colored spores which are harmful to wheat, barley, oats, and other crops. Each year they cause millions of dollars of damage to crops. Smuts are a black, dusty-looking mass of spores they form within the tissues of a plant they are attacking. Smuts infect corn, wheat, oats, barley, and rye.

YEAST Yeast are small, single-celled organisms. Most yeast needs sugar and starches to live which help it produce carbon dioxide gas and alcohol. Yeast is helpful in food production. It makes bread rise and ferment beverages such as wine and beer. It played an initial role in the production of vinegar. Yeast can grow in extreme conditions. This means it can spoil food in meat coolers and refrigerators. It can also spoil sweet foods like honey, jellies, maple syrup, or fermented foods like pickles and sauerkraut which bacteria cannot. Some yeast can cause infections, but they are much less common than bacterial infections.

FUNGI ARE HELPFUL AND HARMFUL Fungi are both helpful and harmful Helpful Food (mushrooms, bread, etc.) Fermentation of food (soy sauce, vinegar, alcohol) HARMFUL Disease (athletes foot) Ring worm Poisonous mushrooms Some are toxic to humans, animals, and plants