Fungi Flashcards
Why are fungi not well known?
Their is an estimated 1.5 million species but only 7% of predicted land fungi have been documented
What is a major role of fungi in ecosystem?
he decomposition of plant and animal tissues; play a critical role in cycling carbon
What is the growth and nutrition charcatersitcis of fungi?
heterotrophs - depend on preexisting organic molecules for carbon and energy
absorb organic molecules directly through their cell walls
secrete enzymes that break down complex organic molecules into simpler compounds that can be absorbed
What are most fungi?
multicellular (except yeast) consisting of hyphae that make up the mycelium
What are hyphae?
highly branched filaments - that increase surface area for absorption of nutrients
What is the mycelium?
a network of hyphae - even greater surface area
What is the largest fungi?
Armillaria ostoyae - over 2000 acres - Blue Mountains of Oregon - weighs hundreds of tons
What are septate hyphae?
hyphae with partitions or cross-walls, often with central pores
What are aseptate hyphae?
no cross-walls in hyphae - ‘contained in a common cytoplasm’ - multinucleate (=coencytic)
What are the cell walls of hyphae?
made of chitin and glucans; more resistant to microbial degradation than cellulose
What is digestion in fungal hyphae?
external, osmotrophic nutrition - secrete enzymes onto food sources, then absorb (osmotically) smaller molecules
What is energy storage in hyphae?
glycogen (like animals and bacteria)
Which fungi don’t produce hyphae?
yeasts
What are yeasts?
single-celled, in moist nutrient rich environments. reproduce by budding.
WHat is budding? (yeasts)
small outgrowths form on original cell that increases in size and eventually breaks off to form a new, identical cell
What are humans uses of yeast?
ferment plant carbs to produce leavened bread and alcoholic bevs
What is fermentation?
chemical process by which molecules such as glucose are broken down anaerobically
What are Saprophytes? How do they get energy?
decomposers sequestering food/energy from organic material of dead organisms
parasite/predators - how do they get energy? (fungi)
organic material from living organisms, by infection or consumption
How do symbionts get energy?
organic material via mutualistic relationships with algae and/or cyanobacteria
What are the ecological roles of fungi?
important biomass
decomposers of the biosphere
parasites/predators, disease agents
symbiotic relationships
What are ecological roles of decomposers?
break down organic material from bodies of dead organisms
release CO2 into atmosphere
return nitrogen and minerals to soil
What is a common biproduct of decomposers?
produce toxic secondary metabolites (mycotoxins) - capable of causing disease and death in both humans and other animals
What are some types of fungal pathogens?
rusts, smuts, and molds (cause huge losses in agricultural production)
What are aboveground plant infections usually transmitted by?
fungal spores
What are belowground plant infections usually transmitted by?
hyphae that penetrate the roots
What are the 3 wasy that fungi can infect plants?
through wounds
through stomata
through epidermal cells directly
What are ways in which fungi are predators?
trap living animals by forming sticky traps with hyphae, or lasso their prey
What are mycorrhizal fungi?
mutualistic relationship - supply plant roots with nutrients such as phosphorus and nitrogen from the soil and, in return, receive carbohydrates from their host plants
What are Lichens?
stable associations between a fungus and photosynthetic microorganisms, green algae or cyanobacteria
What is role of fungus in Lichens?
fungal hyphae that take up water and nutrients from the soil
What is the role of photosynthetic microorganisms in lichens?
provide energy to fungi for growth
Where do Lichens thrive?
harsh environments - arctic, deserts
bare soil, sun-baked rocks, tree trunks, alpine peaks, interior of rocks
What are three forms of Lichen growth?
Crustose, Foliose, Fruticose