FUNGI Flashcards
Morphological characteristics of fungi?
Body form
Unicellular
Filamentous strands called hyphae
Sclerotium (hardened mass of mycelium) overwintering structures
Multicellular life forms: Rhizomorphs, fruiting bodies, Mushrooms
Physiological structures of fungi?
Heterotroph
Saprophytes or saprobes
Feed on dead tissue, or organic waste (decomposers)
Symbionts
Mutually beneficial relationship between a fungus and another organism (mychorriza)
Parasites
Feed on living tissue of a plant or animal host
Pathogens
If the feed of a parasite causes disease on a host organism
Heterotrophic absorption
Fungi obtain carbon source from environmental organic materials, hyphae releases enzymes that break down the substrate (cellulose, lignin, proteins, lipids).
The digestion products (disaccharides, monosaccharides, amino acids, oligopeptides, small lipid molecules) are taken up back by fungal cells.
Store food materials as glycogen.
Fungal hyphae are
Tubular
Tubular structures are interconnected via septums
Chitin cell wall
Multinucleate
Grows through hyphal tip
Fungal cell wall contains
Chitin parallel to plasma membrane, confers strength and cell shape
B-1,3 glucans extend throughout cell wall
Fungal cell wall outer layer
Modified with N- and O- linked oligosaccharides that are covalently associated with proteins from glycoproteins.
Many of outer layer glycoproteins have glycosylphosphatidylinositol GPI anchors tethering them to plasma membrane or to inner wall through more flexible B-1,6 glucans.
Types of reproduction in fungi
Asexual and sexual sporulation
Asexual sporulation
(mitotic origin) mycelial fragmentations or production of asexual sporulation clonal population adapted to a specific environment
Advantages of asexual sporulation
Quicker dispersal and less energy consuming
Sexual sporulation
(meiotic origin) energetically more costly, major fungal groups classified based on sexual fruiting bodies (for example Asci or Basidia)
Advantage of sexual sporulation
Results in greater genetic diversity
