Eukaryotic Microbes 2: Fungi Flashcards
Where are fungi found?
- Everywhere!
- aquatic
- terrestrial
- parasites of plants
- parasites of animals and humans
Explain the fungal nucleus.
- size
- ploidy
- unique features of the fungal nuclei?
- double membrane bound organelle ranging in size from 1-2um to 20-25um in diameter
- most are haploid with 6-20 chromosomes
L> some are naturally diploid
L> others alternate between the two
-membrane remains intact during mitosis
L> no clear metaphase plate.
Fungal cytoplasmic organelles?
- plasma membrane L>phospholipid bilayer -> anchorage for enzymes/proteins such as chitin synthases or glucan synthases L> contains ergosterol - chitosomes L> microvesicles for chitin synthesis
Explain the purpose of the fungal cell wall.
- structural barrier
- environmental interface
L> protects against osmotic lysis
L> contains pigments for protection
L> binding site for molecules
L> mediates interactions with other organisms.
Describe the composition of the fungal cell wall.
- Mannan
- protein
- B-1,3-glucan
- B-1,6-glucan
- chitin
- *58%= glucan
- *36%= Mannan
- 4% = protein
- 2 %= chitin
- be able to draw the cell wall and label these areas.
With respect to the fungal cell wall what does Mannan give it?
- a detectable signature via:
1. O-Mannan -> composed of alpha 1,2 mannose and beta 1,2- mannose.
2. N-Mannan -> composed of alpha 1,2 mannose, beta 1,2- mannose, N acetyl glucosamine, beta 1,4 mannose, alpha 1,6 mannose, alpha 1,3 mannose and Phosphate…. aka IT IS MORE COMPLEX
The growth of fungi:
- What can they look like ( three groups)
- Filamentous
L> moulds and mushrooms - Yeasts (circular shape)
- Dimorphic fungi (mixture)
Describe filamentous fungi!
- what is the main structure?
- Hyphae: rigid tubes containing cytoplasm. Interconnected compartments not individual cells
- long filaments of cells joined end to end = hyphae
Filamentous fungi:
- Describe the two types of hyphae.
- Septate Hyphae
L> joint cells have distinct separations called septa, containing pores (to share cytoplasm) - Coenocytic Hyphae
L> consists of fused cells, multinucleated
Filamentous fungi:
- function of septa?
- offers structural support
- enables differentiation by dividing hyphae into different cells
Filamentous Fungal growth:
typically goes _____ to ____.
- spore to hyphae
Filamentous Fungal growth:
-hyphae typically grow in what fashion?
- by apical growth : extension at the tip
Filamentous Fungal growth:
- what is a mass of hyphae called?
- mycelium –> plural = mycelia
Filamentous Fungal growth:
- Explain vegetative and aerial hyphae.
- vegetative hyphae:
L> grow along the surface , obtain nutrients - Aerial hyphae:
L> stick up from the mycelium, spores for reproduction
Explain the tropisms of hyphal tips.
- they exhibit it to many substances
L> Ex: nutrients, amino acids, volatile metabolites, sex pheromones and light
L> examples species = Phycomyces blakesleeanus (phototropism I believe- double check)
