Fungi in the environment Flashcards
What are the three main types of fungi based on nutritional uptake ?
Saprobes, Mutualistic and parasitic.
What are chemoorganotrophs ?
Organisms that synthesise organic compounds and generate energy from the oxidation of pre formed organic compounds.
What two types of nutrients do chemoorganotrophs uptake and how?
Small organic nutrients are directly absorbed across the cell wall and membrane via diffusion e.g amino acids, sugars
Large organic compounds must be broken down first then absorbed e.g carbs, proteins, lipids
How do exo-enzymes work ?
They are secreted by the fungal hyphae where they digest matter (usually leaf litter).The food is then absorbed by the fungi.
What regulates the expression of exo enzyme genes ?
When the concentration of the substrate is high more genes are produced The is caused by available substrate, ph, temp and moisture.
How is plant litter degraded ?
- Pectin degradedly polygalacturonases and pectin lases.
- Cellullose and semi- cellulose is degraded by cellulases and semi cellulases
- Lignin degraded by phenol oxidase, pheroxidases and laccases
What are the features of Arbuscula mycorrhizae ?
They are obligate biotrophs that are part of the Glomerolycota family that for mutualistic relationships with most herbaceous plant roots.
What are the features of lichens ?
They are fungi that form a symbiosis with photosynthetic algae. The Fungal mass absorbs minerals and protects algae. They can be used as pollution biomarkers.
Name three examples of food producing fungi
Agaricus Bosporus is grown in horse manure and produce the common brown cap mushroom.
Yeast fungi used to make bread marmite and beer.
Fusarium venenatum undergoes process to produce quorn.
What is meant when a fungus has a hemibiotrophic lifestyle ?
When the fungal cells have the ability to grow on living and dead organic matter
What is meant when fungi are nectotrophs ?
Parasitic that kill living cells and feed on the dead matter e.g botrytiscinerea causes fruit mould.
Name an example of fungus that spoil processed food products.
Penecillum roque forti is sound in rye bread
What are mycotoxins and name an example ?
Mycotoxins are toxins produced by certain fungal species that are the most carcinogenic naturally occurring substance. Aflotoxins produced by mould on maize and peanuts in Indonesia cause 20,000 deaths due to liver cancer each year.
