Fungal cell biology Flashcards
Which of the follow cell types possess cell walls?
Plant cell
Animal cell
Fungal hypha
Yeast cell
Spore
All have cell walls but animal cells
Animal cells do not have cell walls. The fungal cell wall is composed mostly of chitin, whereas plant cell wall is primarily cellulose.
Which of these statements on the fungal lifestyle are TRUE or FALSE?
- Fungal hyphae are often multinucleate.
- Cellulose is a major component of fungal cell walls.
- Fungi are phylogenetically closer to bacteria than animal.
- Candida albicans can switch growth forms.
- All fungal spores require sunlight to germinate.
- Schizosaccharomyces pombe grows by budding.
- True
- False
- False
- True
- False
- False
Rank the order of processes during the asexual life cycle of Neurospora crassa:
Hyphal growth
Conidiation
Germination
Colony formation
Branching
Germination
Hyphal growth
Branching
Colony formation
Conidiation
A spore lands, imbibes water, germinates, forms a hypha, branches to form colony, when colony is established it reproduces forming asexual spores called conidia.
What are the characteristics of budding/fission yeast? Whats the difference between the two? Give an example of budding yeast
- Budding yeast starts as a little blip on a cell, wheras fission yeast splits the cell in half
- Has a cell wall
- grows very similarly to bacteria (high moisture)
- Saccharomyces cerevisiae
What are some characteristics of filamentous fungi?
- spore germination
- hyphal tip growth
- Apical vesicle cluster (spitzenkorper)
- do not form golgi stacks
- Hyphae are often multinucleated
What is the difference between cellular and plasmodial slime molds?
Plasmodial slime molds are single celled and multi-nucleated while cellular slime molds are multicellular
How does spore germination work? Describe the process and characteristics
- spore germination needs 1. warmth 2. humidity 3. food source
- spore becomes hyphae becomes mycelium
- germ tubes are specialized hyphae that emerge during spore germiniation
germ tubes important for colony formation
spores fall off gill and into the wind to be distributed
What are specialized about spores that aids their survival?
Can withstand Freezing temperatures, Vacuum, Electron beam / radiation and can germinate afterwards
What is the hyphal tip growth and branching process like?
- Tip growth is polarized extension, increase in cell length is restricted to a narrow region of a few micrometers at the cell tip
- A new spitzenkorper forms, and then that becomes a site of new branch formation
What role does septum formation play in hyphae branching?
- compartmentalizes hyphae
- governs flow of cytoplasm
- provides a ‘damage control’ mechanism
How does mycelium formation occur in Neurospora crassa?
- Hyphal fusion
- Translocation through mycelium networks (nuclear comets transport DNA from the colony to the growing tips)
Why are mycelium networks important? What is a rhizomorph?
- Transport food/nutrients/genetic material across colony
- Thick strands of hyphae that adhered (helps fungi grow quicker and establish feeding network)
- Eg Armillaria mellea rhizmorphs make melanin that protect mycelium from UV/dehydration
What cell signalling mechanisms are used during slime mould, yeast, and fungi growth?
- slime mould: chemotaxis for cAMP
- Yeast: mating factor/pheromone signalling
- Fungi: chemotaxis
cAMP induces growth (pseudopod) for whereever its recepted?
