Ch. 21

 What are fungi? ◦ Eukaryotic heterotrophs that have cell walls made of chitin.  Yeasts, molds and mushrooms

◦ Unlike animals, fungi utilize external digestion. ◦ They come in many shapes and sizes. ◦ They can store lots of water. ◦ Some are parasitic and cause disease. ◦ Some have symbiotic relationships. ◦ Some are delicious!  They are important decomposers!

 Except for yeasts, fungi are made of thin filaments called hyphae.

 A mass of tangled hyphae is called a mycelium. ◦ Most of the mycelium is underground. ◦ The mycelial mat secretes digestive enzymes, and absorbs the end products of digestion.

 Fungi can reproduce both sexually and asexually. ◦ The visible part of a fungus above ground is the fruiting body.  Fungi spread by producing spores in the fruiting body.  Mold spores can cause respiratory illness.