FungiChapter 20

Categories of Fungi

1. Multicellular

– Most fungi

– Do not contain chloroplasts

2. Unicellular

– “Yeasts”

Cell Walls

• Plants - made of cellulose

• Fungi - made of chitin

–Chitin is strong and flexible

Fungi Parts - Hyphae

• Threadlike filaments that make up the basic structure of the fungi’s body (all parts)

• Provide support• Provide a large surface area for

nutrient absorption • Fig. 20.2 (p. 577)

Fungi Parts - Mycelium

• A netlike mass made up many hyphae

• Formed below ground

• Absorb nutrients• Fig. 20.2

Fungi Parts - Fruiting Body

• Reproductive structure

• Above ground portion• Fig. 20.2

Obtaining Nutrients & Energy

1. Through Decomposition• Saprophytic fungi - feeds

on dead organisms or organic wastes

• Recycle nutrients• Fig. 20.4

Obtaining Nutrients & Energy

2. Through Parasitism

–Absorb nutrients from living cells of another organisms (a host)

–Fig. 20.4

Obtaining Nutrients & Energy

3. Through Mutualism

–With another organism, such as a plant or alga

• Ex: mycelia on a root of a soybean plant– Fungus receives sugar from the host plant– Mycelia increase water uptake and mineral absorption

for the host plant– Fig. 20.4

Branches of Fungi1. Chytrids

• yeast2. Common Molds

• bread mold3. Sac Fungi

• morels & truffles, yeast, penicillin producer4. Club Fungi

• mushrooms• Fig. 20.8

Imperfect Fungi

• Very diverse group

• Lack a sexual stage of reproduction

–Called “Imperfect Fungi”

Benefits of Fungi• Decomposers - recycle nutrients• Medical uses - penicillin (antibiotic),

reduce high blood pressure, control excessive bleeding, treat migtaine headaches, promote contractions during childbirth, prevent organ rejection in organ transplant patients

• Food - mushrooms, yeast, truffles• Bioremediation - cleaning the

environment of pollutants

Harmful Fungi• American elm trees & American chestnut

trees killed by certain fungi• Agricultural crops damaged• Can act as parasites in humans & other

organisms–Athlete’s foot, ringworm, yeast

infections• Fig. 20.15

Moldy Bread

• Why should you throw away the whole loaf of bread, even if the mold only appeared on one piece?