INTRODUCTION 22-1 Chapter 22 Fungi

Fungi Some of the most unusual and peculiar organisms on earth are members of the Kingdom Fungi.

I. Fungi are Classified In their own Kingdom  A. Fungi are Eukaryotic and mostly multicellular organisms (yeast are unicellular).  1. Fungi were first classified with plants because they were immobile and appear “rooted” in the soil.

B. Differences between fungi and plants  1. Fungi are heterotrophic. They do not contain chlorophyll and obtain their energy by absorbing organic molecules from their surroundings  2. Fungi have filamentous bodies. Plants have a variety of cell and tissue types. Fungi are made of long slender filaments woven tightly together to form the fungus reproductive structures.

3. Fungal cell walls contain chitin. Chitin is found in the exoskeleton of insects and arthropods. Plant cell walls are made of cellulose. 4. Fungi have nuclear mitosis. The nuclear envelope disappears in mitosis of plants-mitosis takes place in the nuclear envelope. The nuclear envelope remains during mitosis in fungi. Mitosis takes place in the nuclear envelope rather than the cell.

C. Fungi are well suited for Absorbing nutrients.  1. The part of fungi we actually see is the reproductive structure of the fungus. The hypha lies woven within the tissues or underground.  2. Bodies (except yeast) are made of filaments called hyphae. Hyphae tangle together and make a mass called mycelium.  3. Each of the Hyphae are divided into a long string of cells by septa – partial dividers that let cytoplasm flow freely from cell to cell- many have several nuclei.

D. Obtaining Food  1. All fungi digest food outside their bodies.  2. they secrete powerful digestive enzymes that break down organic matter into small molecules.  3. These molecules are then absorbed by the fungus and used as energy.  4. Nonliving organic matter – leaves, branches, animal corpses, and waste materials  5. Living hosts – Which they weaken and often infect with disease (plants and animals)  6. fungi often attack materials humans consider inedible – paper, cardboard, cloth, paint, leather, waxes, fuel, and petroleum.

E. Commercial benefits  1. Yeast – produce CO2 and ethanol. They are used in baking, brewing, and wine making.  2. Cheese – blue cheese, etc. Making of foods  3. Antibiotics – penicillin and cyclosporine ( used to suppress the immune system during organ transplants.