Lecture 3: Eukaryotes Flashcards
What are chemoheterotrophs?
Decompose organic matter to obtain energy.
Describe how facultative anaerobes function.
They prefer oxygen or aerobic environments but they can switch to fermentation or anaerobic respiration if oxygen is not available.
Fungi tend to be ________, and to grow in ________
multicellular; colonies
What are hyphae?
Long filaments of cells joined together.
What are septa?
Contain cross walls
What is a thalus?
The whole body of mold.
How do vegetative hyphae obtain nutrients?
By catabolism
What do aerial hyphae do?
Reproduce
How are yeast different from most other fungi?
They are unicellular and non-filamentous.
How do yeast divide?
By budding or fission
The most pathogenic species of fungi often exhibit _________, two forms of growth.
Dimorphism; they can grow as mild or yeast
How do fungi reproduce?
Either sexually or asexually via formation of spores that detach from the parent.
How are asexual spores produced?
Produced by mitosis and subsequent cell division.
What does conidiospore mean?
Not enclosed in a sac.
What does sporangiospore mean?
Enclosed in a sac.
Talk about fusion of sexual spores…
If one spore does not find another complementary spore (opposite polarity) it will simply die. If it does mate it will fuse directly.
Plasmogamy (first phase of sexual reproduction)
Haploid donor cell nucleus (+) penetrates cytoplasm of recipient cell (-)
Karyogamy (second stage of sexual reproduction)
(+) and (-) nuclei fuse and form a diploid zygote
Meiosis (third stage of sexual reproduction)
Diploid nucleus produces haploid nuclei (sexual spores).
What are some nutritional adaptations that are complementary for fungi?
- Grow better at pH of 5
- Grow in high sugar and salt concentration; resistant to osmotic pressure
- Can grow in low moisture content
- Can metabolize complex carbohydrates
Zygomycota
Black fungus (1050 species known)
Microsporidia
Do not have mitochondria. Mainly related with deficiency of immune system such as AIDS patients, kids etc.
Ascomycota
Largest phylum of fungi with 64,000 species.
Basidiomycota
Includes: mushrooms, puffballs, stinkhorns, bracket fungi, other polypores, jelly fungi, boletes, chanterelles, earth stars, smuts, bunts, rusts, mirror yeasts, and the human pathogenic yeast Cryptococcus.
Basidiomycota are filamentous fungi composed of hyphae (except for yeasts), and reproducing sexually via the formation of specialized club-shaped end cells called basidia that normally bear external meiospores (usually four) called basidiospores.
Cutaneous mycoses
Fungal infection that can grow in all the layers of the skin, affecting hair, skin and nails.
Systemic mycoses
Fungal infection deep within the body such as in the lung or large intestine.
Subcutaneous mycoses
Fungal infection beneath the skin.
Superficial mycoses
Localized fungal infection, eg. hair shafts