Chap 12 Flashcards
Mycology
Study of fungi
Chemoheterotrophs function
Decompose organic matter
Arthropods
animals with jointed legs, ticks, insects, mosquitoes
Helminths
multicellular animals; chemoheterotrophs
Helmiths get nutrients by
ingestion through mouth or by absorbing food.
Often have elaborate life cycles
parasitic helminths, egg, larvae adult
Fungi get food by __________. They are chemoheterotrophs
absorption
Fungi are multicellular with the exception of
yeasts
Fungi reproduce with
sexual and asexual spores
Algae belong to several
super clades
Algae are photoautotrophs, meaning,
they produce several different photosynthetic pigments
Algae obtain nutrients by
diffusion
Some are multicellular forming colonies, filaments of even tissues. A few produce toxins
Algae
Most protozoa are chemoheterotrophic, meaning
Most get nutrients by absorption or ingestion
Chemoheterotroph
organism that obtains its energy from chemical compounds (chemo) and its carbon source from organic compounds (heterotroph)
some protozoa are photoautotrophic
make organic material for energy
Protozoa are unicellular or multicellular?
unicellular
often form resistant cysts
protozoa
mycorrrhizae
A fungus growing in symbiosis with plant roots
Fungi are identified on the basis of
1.physical appearance:
2.colony characteristsics, 3.reproductive spores
vegetative
referring to cells involved with obtaining nutrients as opposed to reproduction.
Fungi anaerobe or aerobe?
can be both:
1. Aerobic
2. Facultative anaerobic
Facultative anaerobe
Can adapt metabolism to live in oxygen rich and oxygen poor environments
Cell type of fungi vs bacteria
fungi: eukaryotic
Bacteria: prokaryotic
Cell membrane of fungi vs bacteria
fungi: has sterols
bacteria: only mycoplasma have sterols
Cell wall of fungi vs bacteria
fungi: Glucans, mannans, chitin (no peptidoglycan)
Bacteria: peptidoglycan
Spores of fungi vs bacteria
Fungi: Sexual and asexual reproductive spores
Bacteria: Endospores(not for reproduction); some asexual reproductive spores
Metabolism fungi
Fungi: Limited to heterotrophic; aerobic, facultatively anaerobic
Metabolism of bacteria
Heterotrophic, autotrophic, aerobic, facultatively anaerobic, anaerobic
In molds and fleshy fungi, the thallus is
the body
The thallus is made of
hyphae: long filaments of cells joined together
hyphae
long filaments of cells joined together
mycelium
mass of hyphae
Septate hyphae
cross walls of hyphae that divide them into cell-like units
Coenocytic hyphae
fungal filament not divided into uninucleate cell-like units because it lacks septa
Vegetative hyphae
Portion of hypha that obtains nutrients
Aerial hyphae
involved with reproduction; bear reproductive spores
hyphae can grow by
elongating at the tips, each new fragment is capable of growth. Fungi are usually grown from fragments of a fungal thallus
How do fungal colonies differ from bacterial colonies?
fungal colonies spread more widely and appear less defined compared to bacterial colonies
Yeasts
nonfilamentous, unicellular fungi
frequently found as a white powdery coating on fruits and leaves
yeasts
Budding yeast
DIVIDES UNEVENLY
following mitosis, a yeast cell that divides unevenly to produce a small cell (bud) from the parent cell
Saccharomyces
type of budding yeast that divides unevenly
Fission yeasts
divide evenly
Dimorphic fungi
Yeastlike at 37 -C and moldlike at 25 -C
pseudohypha
short chain of fungal cells where daughter cells don’t separate after budding
One ______ cell can in time produce up to 24 daughter cells by budding.
yeast
How does a bud differ from a spore?
a bud is a visible, localized growth on the parent, while a spore is a tiny, dispersed unit that can travel further to establish a new organism
Fungi reproduce sexually and asexually via the formation of spores that
detach from the parent and germinate into a new mold
Asexual spores
Produced via
mitosis and cell division; formed by the hyphae of one organism
Conidiospore is not enclosed in
not enclosed in a sac
Arthroconidia
fragmentation of septate hyphae
Blastoconidia
buds of the parent cell
Chlamydoconidium
spore within a hyphal segment
Sporangiospore
enclosed in a sac
Sexual spores
Fusion of
nuclei from two opposite mating strains
Three phases of sexual reproduction
- Plasmogany
- Karyogamy
- Meiosis
Plasmogamy:
fusion of cytoplasm of two cells; occurs in sexual stage of fungal life cycle
haploid donor cell nucleus (+) penetrates cytoplasm of recipient cell (-)
plasmogamy
Karyogamy
(+) & (-) nuclei fuse and form diploid zygote
Meiosis:
diploid nucleus produces haploid nuclei (sexual spores)
generally adapted to environments that would be hostile to bacteria.
fungi
ideal pH to grow fungi
5
Fungi are resistant to osmotic pressure; meaning
Fungi grows well in high sugar and salt concentration
Fungi can grow on substances with a very low _________ content
moisture
Fungi require somewhat less ________ than bacteria for an equivalent amount of growth.
nitrogen
Fungi are often capable of metabolizing _________ _______________, such as lignin (a component of wood), that most bacteria can’t use for nutrients.
complex carbohydrates
Assume you isolated a single-celled organism that has a cell wall. How would you determine that it is a fungus and not a bacterium?
The cell wall of a fungus : glucans, mannans, chitin, fungus will have sterols in its cell membrane
bacterium cell wall: will not have sterols in its cell membrane. If its gram-positive, itll have a peptidoglycan cell wall
Contrast the mechanism of sexual and asexual spore formation
two distinct parent cells (gametes) fuse together through a process called plasmogamy, leading to the formation of a diploid zygote which then undergoes meiosis to produce haploid sexual spores; whereas, asexual spore formation occurs through mitosis
Medically Important Fungi
Zygomycota
Microsporidia
Ascomycota
Basidiomycota
What kind of fungi is Zygomycota?
Conjugation fungi
with coenocytic hyphae
Conjugation fungi
Reproduce sexually through conjugation
Coenocytic hyphae
nonseptate, meaning they are a long cell without compartments
How are zygomycota produced asexually?
sporangiospore
How are zygomycota produced sexually?
zygospore
Zygospore
made when the nuclei of two similar cells fuse
Microsporidia
unusual eukaryotes because they lack mitochondria
Why were microsporidians reclassified as as protists and not fungi?
They lack mitochondria
Why were microsporidians classified as fungi?
genome sequencing says they are fungi
Sexual reproduction of microsporidia
Hasn’t been observed, but probably takes place in the host
Microsporidia are obligate intracellular parasites, meaning
cannot reproduce outside of their host cell
Ascomycota means
means sac fungi
Ascomycota includes
molds with septate hyphae and some yeasts.
Ascomycota asexual spores are usually produced how?
conidia produced, in long chains from conidiophore
conidia means
dust, spores freely detach from the chain at the slightest disturbance and float in the air like dust.
ascospore
sexual fungal spore made in an ascus, made by the ascomycetes
ascus
saclike structure containing ascospores; found in the ascomycetes.
Ascomycota are a type of Teleomorphic fungi, meaning
produce sexual and asexual spores
Some ascomycota are anamorphic, meaning
They lose the ability to sexually reproduce
Spores produced asexually by Ascomycota
conidiospore
spores produced sexually by ascomycota
ascospore
Nuclei morphologically similar or dissimilar fuse in a saclike _____
ascus
Basidiomycota
club fungi; phylum includes fungi that produce mushrooms
club fungi, also possess septate hyphae
Basidiomycota
Basidiospore
sexual fungal spore made in a basidium
Basidium
pedestal that makes basidiospores; found in basidiomycetes
How do Basidiomycota reproduce asexually?
conidiospores
On what basis are fungi classified into phyla?
1.life cycles
2.mode of reproduction
3. cell wall and
4.septum structure
teleomorphs
sexual stage in a lifecycle of a fungus; fungus that produces sexual and asexual spores.
Mycosis
fungal infection
Systemic mycoses
deep within the body
Subcutaneous mycoses
beneath the skin
Cutaneous mycoses
affect hair, skin, and nails
Superficial mycoses
localized (e.g., hair shafts) Fungi grows along hair shaft and on superficial epidermal cells. Prevalent in tropical climates
Opportunistic mycoses
fungi harmless in normal habitat but pathogenic in a compromised host
Are yeasts beneficial or harmful?
Beneficial:
-make bread, beer,
Harmful: can cause thrush and other infections
Saccharomyces cerevisiae
bread, wine, hepatitis B vaccine
Trichoderma
Makes cellulase; used to remove plant cell walls to produce a clear fruit juice
fungus Taxomyces
anticancer drug taxol, also found in yew trees
Entomophaga
killed gypsy moths. Used to kill pests. Biocontrol
Coniothyrium minitans
kills fungi on crops. feeds on fungi that destroy soybeans and other bean crops.
Paecilomyces
kills termites
attaches to human epithelial cells as a yeast but usually requires pseudohyphae to invade deeper tissues
Candida albicans
Lichen
combination of green alga (or cyanobacterium) and a fungus
Lichens are placed in the kingdom
Fungi
Lichens are classified according to
the fungal partner, most often an ascomycete