21.4 - fungi
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21.4 - Fungi. Fungi and You. Believe it or not, fungi play an important role in your life. The bread you eat, the salad you make, and the medicine that you take when you are sick may include various types of fungi or products made from fungi. 1. List as many examples of fungi that you can. - PowerPoint PPT PresentationTRANSCRIPT
21.4 - Fungi
Fungi and You
Believe it or not, fungi play an important role inyour life. The bread you eat, the salad you make,
and the medicine that you take when you aresick may include various types of fungi or
products made from fungi.
1. List as many examples of fungi that you can.2. How are fungi helpful to humans?3. How are fungi harmful to humans?
What Are Fungi?Types: mushrooms, mold, yeast, mildew, truffles
Basic characteristics:• Heterotrophic eukaryotes • Many feed by absorbing nutrients from
decaying matter• Others live as parasites absorb nutrients from
their hosts
What Are Fungi?• Cell walls made of chitin (polymer of modified
sugars, also found in arthropod exoskeletons)– Evidence that fungi are more closely related to
animals than plants• Instead of photosynthesis, fungi produce
enzymes that digest food outside their bodies, then absorb the small molecules released by the enzymes
Structure and Function yeasts – single-celled mushrooms - multi-celled• hyphae - long, slender branching
filaments • mycelium - mass of branching hyphae
below the soil• mushroom fruiting body – reproductive
structure that grows above soil• clusters of mushrooms are often part of
the same mycelium -> same organism
Reproduction• Asexually – release spores that travel through
air/water or break off a hypha• Sexually – transfer of nuclei and cytoplasm
from one hypha to another, then create spores
Diversity of Fungi
• more than 100,000 species of fungi
• major groups differ in their reproductive structures
The Ecology of Fungi1. Decomposition champions help ecosystems by
breaking down dead organisms/recycling essential elements and nutrients
2. Parasitic fungi cause serious diseases in plants and animals
3. Mutualistic associations with photosynthetic organisms in which both partners benefit
Decomposition • Organisms remove
important trace elements and nutrients from the soil
• Fungi release digestive enzymes that break down leaves, fruit, and other organic material into simple molecules
• Fungi then recycles these elements and nutrients
• If not returned, the soil would quickly be depleted
ParasitismPlant Diseases • Parasitic fungi cause diseases that threaten
food crops– ex: mildews infect a wide variety of
plants– ex: corn smut destroys corn kernels
ParasitismAnimal Diseases • Infect insects, frogs, and mammals
- ex: Cordyceps fungus infects grasshoppers in rain forests in Costa RicaGrasshopper eats spores,
germinate and produce enzymes that slowly digest all cells and
tissues until the insect dies, hyphae develop on dead grasshopper and
produce more spores spreading the infection
Human Diseases • Ex: athlete’s foot forms a
mycelium in the outer layers of the skin, which produces a red, inflamed sore from which the spores can easily spread from person to person
• Ex: yeast Candida albicans responsible for vaginal yeast infections and for infections of the mouth called thrush
Symbiotic Mutualism • Lichens - mutualistic association between
fungus + photosynthetic organism- Photosynthetic organism - green alga/ cyanobacterium
• Algae photosynthesize source of energy• Fungus provides water and minerals
The Lichen is created between the fungus and the alga.
The Lichen is created between the fungus and the alga
Mr. Fungus is ready to greet our friend the alga
Friend alga cell is prepared to greet Mr. Fungus
Lichen =Fungus + photosynthetic organism
Symbiotic Mutualism
• Mycorrhizae – mutualistic relationships between fungus + plant roots- Essential for plant growth
• Fungi hyphae collect water/minerals and bring them to the roots, also release enzymes that free nutrients in the soil
• Plants provide fungi w/ the products of photosynthesis (oxygen and sugar)