Fungal Cell biology L19 Flashcards
What are key differences between fungal, animal, plant, and prokaryotic cells?
Fungal cells: chitin cell wall, eukaryotic, heterotrophic
Animal cells: no cell wall, eukaryotic, heterotrophic
Plant cells: cellulose cell wall, eukaryotic, autotrophic
Prokaryotic cells: no nucleus, peptidoglycan wall, unicellular
Difference between cellular and plasmodial slime moulds?
Cellular: individual amoeboid cells that aggregate (e.g. Dictyostelium)
Plasmodial: single multinucleate mass (e.g. Physarum)
: Difference between yeasts and filamentous fungi?
yeasts: unicellular, reproduce by budding/fission
Filamentous fungi: multicellular, grow via hyphae/mycelium
What makes yeasts successful as single-celled organisms?
Rapid growth, flexible metabolism, asexual & sexual reproduction
Budding vs Fission Yeasts?
Budding (e.g. S. cerevisiae): asymmetric division
Fission (e.g. S. pombe): symmetric division
What is spore germination?
Activation of spores to grow under favorable conditions.
How do fungal hyphae grow?
Tip growth: expansion at apex
Branching: increases surface area for absorption
What is the role of septa in hyphae?
Compartmentalise hyphae
Control cytoplasmic flow
Prevent damage spread if injured
How does Neurospora crassa develop mycelium?
Germination → hyphal extension → branching → fusion
Regulated by signalling pathways & environmental cue
Why is the mycelial network important?
Long-distance transport of water, nutrients, genetic material
Acts like a fungal “circulatory system”
What’s special about fungal hyphae/spores’ internal structure?
Organelles (nuclei, vacuoles, mitochondria) organized along cytoskeleton
High nuclear number supports rapid spore production and gene expression
Examples of fungal signalling mechanisms?
Slime moulds: cAMP waves for aggregation (Dictyostelium)
Yeasts: pheromone signalling for mating
Filamentous fungi: MAPK pathways regulate hyphal growth and fusion
what is tip growth
involves polarised extension in which the increase in cell length is restricted to a narrow region of a few micrometers at cell tip
Golgi cisternae
involved in glycosylation and packaging in vesicles of secreted and integral membrane proteins
hyphal fusion
hyphal branches grow towards each other in older parts of fungal colony
What are filamentous fungi composed of?
Long, branched hyphae that form a mycelium
What is tip growth?
Polarised cell extension limited to the apex of the hypha
What organelle regulates hyphal tip growth?
The Spitzenkörper – a vesicle-rich structure at the tip
What initiates new hyphal branches?
Formation of a new Spitzenkörper at the branch site
What is a septum in fungi
A cross-wall that divides hyphae into compartments
Allow cytoplasmic flow
Limit damage spread (pores seal after injury)
What is hyphal fusion?
Hyphae grow toward each other and fuse, allowing cytoplasmic exchange
why are there many nuclei in fungal hyphae/spores?
Enables rapid gene expression and spore production
