BI 101 Lecture Notes: KINGDOM FUNGI: Chapter 20

First: Some definitions:

A) Diploid: has full set (2 copies) of genetic material (2n) Ex: Typical human cell

B) Haploid: only has one copy of genetic material (1n) Ex: Sex cells (i.e. sperm or eggs)

C) Meiosis: Type of cell division (diploid---> haploid)

d) Mitosis: Type of cell division (haploid--> haploid) or (diploid---> diploid)

I. What Are the Main Adaptations of Fungi?

A) Most fungi have a body made up of a mycelium, an interwoven mass of hyphae.

B) Hyphae: threadlike filaments (typically haploid)

1. Can be a single cell with many nuclei or many separate cells

2. mycelia may form a “fruiting body”.

C) Fungal cell walls

1. Chitin a modified glucose molecule that contains nitrogen. Also in insect exoskeletons

2. Fungi “move” by hyphae: they can grow rapidly in any direction within suitable environments

3. BODY FORM reflects BODY FUNCTION

D) Fungal Nutrition

1. saprobes: digest the bodies of dead organisms

2. parasites: They feed on living organisms, causing disease

3. mutualistic symbiotic relationships with other organisms

4. Predatory Traps and digests small nematodes (roundworms)

E) Types of Fungal Reproduction

1. Simple asexual reproduction: mycelium breaks into pieces

2. Asexual spores: Mitotic division of haploid hyphal cells

– sporangia forms spores --> grow into new hyphae

3. Sexual spores: Fusion of haploid cells produce diploid cell

– undergo meiosis to make haploid sexual spores

II. How Are Fungi Classified? : based on reproductive stages

A) Zygote fungi: Zygomycota Examples: soft fruit rot and bread mold

1. Asexual reproduction

2. Sexually reproduce with diploid zygospore structure

3. Haploid cells from hyphae of different mating types

4. fuse sexually to produce diploid zygospores

5. disperse then undergo meiosis to produce new hyphae

B) The sac fungi (Ascomycota) molds, morels, truffles, Dutch elm disease, chestnut blight, yeasts, Penicilium

1. Asexual reproduction

2. Sexual Reproduction: ascospores in sacs called asci (singular = ascus)

C) The Chytrids (Chytridiomycota)

1. Unusual fungus because it lives in water, has swimming spores and flagella

2. May have given rise to other groups of fungi

3. Aquatic decomposers and Parasites

D) The club fungi (Basidiomycota): mushrooms, puffballs, shelf fungi, parasitic rusts and smuts of grain

1. Club-shaped reproductive structures (basidia) containing sexual spores (basidiospores)

E) The imperfect fungi (Deuteromycota) Unclassified: Sexual structures not yet observed

1. Ringworm and athlete's foot, predators of roundworms

F) Symbiotic Fungi

1) Lichens

1. Fungi (Ascomycetes) + photosynthetic green algae and or cyanobacteria

2. Fungus provides support and water, gets food from the algal or bacterial partner

2) Mycorrhizae

1. Basidiomycetes or Ascomycetes symbiotic with ~80% of all plants

2. Hyphae invade root cells and increase root surface area, helping plant obtain nutrients/water, and plant provides sugar to fungal cells??

III. How Do Fungi Affect Humans?

A) Food, but some mushrooms are extremely poisonous

B) Decomposers

C) Parasites: human diseases, crop damage, plant diseases

D) Others are Helpful: Farmers use "fungal pesticides", and yeasts used for bread wine, etc.