Lab 5: Fungi Flashcards
State the major roles of fungi in ecosystems
- Fungi are the master recyclers in terrestrial ecosystems.
• Saprophytes digest dead plant material.
• Play a key role in cycling of carbon.
• Along with a few bacteria, are the ONLY organisms capable of digesting lignin and cellulose!
• Can completely break down wood!!
• Without fungi, carbon would be trapped for a long time; terrestrial environments would be less productive. - Fungi form important mutualistic relationships
• Mycorrhizal fungi
• Mycorrhizae are mutually beneficial
relationships that occur between plant roots
and fungi.
• Without these fungi, plant growth slows.
• Endophytic fungi
• Live in aboveground parts of plants.
• Newish discovery- still much to learn
• e.g., Endophytes in some grasses produce
compounds that deter or even kill herbivores. - Parasitic fungi can cause economic losses and illness
• 30% of the known species of fungi make a living as parasites, mostly of plants.
• 80% of plant diseases are due to fungi.
• Rusts, smuts, mildews, wilts, and blights cause billions of dollars of crop loss annually.
• Some fungi that attack food crops produce compounds that are toxic to humans (e.g., Aflatoxins found in peanuts + grain; Ergotism from infected rye)
• Athletes foot, diaper rash, ringworm, pneumonia, and thrush are all examples of human ailments
caused by parasitic fungi.
4 . Parasitic fungi can also have ecological impacts
- . Saprophytic fungi are responsible for food spoilage
- Penicillin and mushrooms
List the general characteristics of fungi that distinguish them from members of other multicellular kingdoms.
They are all absorptive chemoheterotrophs. They secrete hydrolytic enzymes into the surrounding substrate and then absorb the products of enzymatic degradaion
All are non-motile, but compensate through rapid growth and increased surface area to maintain contact with fresh food supplies
size varies from unicellular yeast that are found in wet habitats to the more common multiceullular species. The bodies of multicellular fungi are made up of tiny filaments called hyphae. An interwoven mass of fungal hyphae is referred to as mycelium. Some species switch between yeast and mycelial forms depending on the amount of moisture present
Like plants most fungi have cells walls but unlike plants, their walls are composed of chitin, a nitrogen containg polysaccharideidentical to that found in the exoskeleton of athropods
most fungi reproduce asexually ususally through some form of mitosis. In yeast asexual reproduction is called budding, while in mycelial fungi asexual spores are produced in specialized structures called sporangia, or on special stalks called condiophores which produce external spores called conidia
Explain how fungi acquire their nutrients.
They are all absorptive chemoheterotrophs. They secrete hydrolytic enzymes into the surrounding substrate and then absorb the products of enzymatic degradaion
Describe the basic body plan of a fungus and state the exception to this body plan.
size varies from unicellular yeast that are found in wet habitats to the more common multiceullular species. The bodies of multicellular fungi are made up of tiny filaments called hyphae. An interwoven mass of fungal hyphae is referred to as mycelium. Some species switch between yeast and mycelial forms depending on the amount of moisture present
Differentiate between coenocytic and septate fungi.
In most fungi the hyphae are divided into cells by cross walls or septa.
• Septa have pores large enough for ribosomes, mitochondria, and even nuclei to flow from cell to cell.
• Fungi that lack septa are called coenocytic
fungi.
• Consist of a continuous cytoplasmic mass with hundreds or thousands of nuclei.
Draw and explain a diagram illustrating the basic (generalized) lifecycle of a fungus, including asexual and sexual reproduction. Identify the haploid, diploid, and heterokaryotic stages.
Draw in notes
Given specimens or images, recognize the sexual structures that characterize Zygomycota, Ascomycota, and Basdiomycota, or be able to sketch, name, and describe these structures. For Ascomycota and Basidiomycota, you should be able to name and identify BOTH the sexual spore producing structures and the fruiting bodies that contain them. Hint: For Zygomycota you should be able to recognize the zygosporangium. For ascomycetes, think “cups” for identifying the fruiting body and “sacs” for the asci, and for basidiomycetes think “gills” or “pores” for identifying the fruiting body and “pedestals” or “clubs” for the basidia.
NOTES
Differentiate between the asexual spores (and sporangia) produced by zygomycetes and the conidia (and conidiophores) produced by ascomycetes.
In yeast asexual reproduction is called budding, while in mycelial fungi asexual spores are produced in specialized structures called sporangia, or on special stalks called condiophores which produce external spores called conidia
Describe mycorrhizae and lichens and explain the role of each organism involved in these mutualistic relationships.
lichens are stable associations between green algea and fungi or cyanobacteria and fungi
Roles: algea or cyanobacteria in lichen are protected from dying by the fungus and in return they provide sugars to the fungi that they produced via photosynthesis
mycorrhizea - literally called fungus roots.
Roles: In some habitats trees and shrubs receive large amounts of nitrogen from mycorrhizal fungi. In return plants transfer sugars and photosyntheitc products to the fungi
