Chapter 12- Eukaryotes (EXAM 2) Flashcards
Almost all molds are ________; most yeast are __________ __________; bacteria vary
aerobic; facultative anaerobes
Most fungi can tolerate lower _____s and higher _________ _________ (i.e. higher sugar and salt concentrations) than bacteria
pHs; osmotic pressure
________ require less moisture and nitrogen for growth than ________
fungi; bacteria
Fungi can metabolize complex ____________ for energy (i.e. ________, a component of wood) that most bacteria cannot use
carbohydrates; lignin
mycology
the study of fungi
What are some harmful effects of fungi? (2)
- Medically, fungal infections increasing over last 10 yrs due to health care
related infections and more people with compromised immune systems - Commercially, cause an estimated $1 billion dollars in damages to crops
annually
What are some beneficial effects of fungi? (3)
• Critical for maintenance of the food chain/replenishment of soil nutrients
via decomposition of dead plant material, especially those parts animals can’t break down
• nearly all plants depend on symbiotic fungi
(Mycorrhizae) which aid roots in absorbing
nutrients from the soil
• used by humans as food (mushrooms), and to produce food (bread and citric acid) and drugs (alcohol and penicillin)
what nutritional type are fungi?
chemoheterotrophs
are fungi multicellular?
yes, except for yeast
how do fungi acquire food?
absorption
how do fungi reproduce?
sexual and asexual spores
how are most fungi identified?
biochemical tests are used for yeast
However, multicellular fungi are identified on the basis of physical appearance: including colony characteristics and reproductive spores
The fungal _______ (body) consists of
filamentous structures called _______
thallus; hyphae
multinucleated, long, continuous cells
Coenocytic Hyphae
uninucleated ,cell like units created by the formation of septa with a pore in the center
Septate Hyphae
portion that anchors and absorbs nutrients
vegetative hyphae
portion of the hyphae concerned with growth; projects above the surface of the medium
Reproductive/ Aerial Hypha
Under favorable conditions a fungus can
colonize a substrate and produce masses of
hyphae visible to the eye. What is this mass called?
A hyphal mass is referred to as a mycelium.
Non-filamentous, unicellular fungi
Typically spherical or oval
yeast
what are the two methods by which yeast divide by?
- fission yeasts
2. budding yeasts
divide symmetrically; eg Schizosaccharomyces pombe
fission yeast
divide asymmetrically; eg Saccharomyces
cerevisiae
budding yeast
Buds that fail to detach from the parent cell form structures known as ____________
pseudohyphae
a human pathogen that requires the
formation of pseudohyphae to aid in its pathogenicity
Candida albicans
One yeast cell can in time produce
approximately ____ daughter cells by budding
24
Why is it beneficial for yeast to undergo respiration or fermentation?
Yeast can use O2 or an organic compound as final e acceptor (respiration or fermentation)
- This allows them to inhabit more environments
For yeasts, which is preferred: aerobic or anaerobic respiration?
aerobic
in absence of ______, yeast can ferment carbohydrates to yield ______ and ______
O2; EtOH; CO2
describes the phenomenon whereby the yeast S. cerevisiae, produces EtOH aerobically in the presence of high
external glucose concentrations
Crabtree Effect
What are some commercial uses of S. cerevisiae
- alcoholic beverage production
- leavening agent for bread production
What are fungi that grow either as a mold, forming hyphae, or as a yeast through budding called?
dimorphic fungi
Dimorphism in fungi can triggered by ___________ and _____ levels.
temperature; CO2
Dimorphism in ________ fungi is predominately temperature dependent, yeast-like at _____C and mold-like at ____C
pathogenic; 37; 25
yeast pathogens are more dangerous to humans because they thrive at physiologic temperatures
filamentous fungi can reproduce asexually by
____________ of their hyphae
fragmentation
unlike bacterial endospores, fungi are true __________ spores. Detaches from parent and germinates into _____ ______
reproduction; new mold
Which type of spore is genetically identical to the parent; and originate from a single hyphae?
asexual spores
Which type of spores arise from the fusion of nuclei from two opposite mating strains of the same fungal species?
sexual spores
Fungi that reproduce both sexually and asexually
telomorphs
Fungi that reproduce only asexually
anamorphs
a spore not enclosed in a sac
Conidiospore/conidium
Conidia is produced in a chain at the end of a _____________
conidiophore
easily dispersed asexual spore
conida = dust
which type of asexual spore is formed within a sac at the end of an aerial hypha?
sporangiospores
one ____________ can contain hundreds of ______________.
sporagium; sporangiospores
what are the two types of asexual spores?
conidiospore/ sporagniospore
types of conidia
Arthroconidia
Blastoconidia
Chlamydoconidia
spore released by fragmentation of a septate hypha, Slightly thicker than the hypha it was produced
Arthroconidia
budding from a parent cel
Blastoconidia
thick-walled spore formed by rounding and enlargement within hyphae
Chlamydoconidia
what are the three phases of sexual reproduction in spores?
Plasmogamy
Karyogamy
Meiosis
union of two haploid cells with mixing of the cytoplasm
Plasmogamy
sexual reporduction phase where + and – nuclei fuse
Karyogamy
Diploid nucleus produces haploid nuclei
(sexual spores), some of which may be genetic
recombinants
meiosis
The sexual spores produced by fungi determine the _______
phyla
However, many fungi reproduce only __________, and cannot be easily placed in a classification based on _________ characters.
asexually; sexual
Historically, fungi whose sexual cycle had not been observed were put in a “holding category” called ____________.
deuteromycota
Medically Important Phyla of Fungi
Zygomycota
Ascomycota
Basidiomycota
Deuteromycetes/Fungi Imperfect
Most are Ascomycota that have lost ability to produce
sexually ( a few are Basidiomycetes) also are classified by rRNA
Deuteromycetes/ Fungi Imperfecti
a large diploid spore enclosed in a thick wall
Zygospore
sexually reproduced spores that are medically important
Zygospore
Ascospore
Basidiospore
What is the sexual spore that has a multi-nucleated diploid reproductive stage resulting from the fusion of the haploid nuclei from two cells
Zygospore
spores produced in saclike structure called an _______
- results from the fusion of the nuclei from two cells. ________ spores are produced during meiosis.
What type of sexual spore is this?
ascus; haploid; Ascospore
What is the sexual spore that has haploid spores formed externally on a __________.
pedestal (basidium);
Basidiospore
Any fungal disease
mycosis
Mycoses are generally _________ infections
because fungi grow slowly
chronic (long-lasting)
since fungi and animals are both ________, drugs
that affect fungal cells may also affect animal cells.
Thus, fungal infections in animals and humans are
often hard to treat
eukaryotic
Mycoses are classified into _____ groups according
to the degree of tissue involvement and mode of
entry into the host
five
Degrees of Mycoses (5)
Superficial Cutaneous or Dermatomycoses Subcutaneous Systematic Opportunistic
limited to the outermost layers of the skin and hair. Infections prevalent in tropical climates.
superficial
infect only the nails, skin and hair. These fungi are called ___________. Transmission occurs from either human or animal to human by ___________ or contact with __________ etc)
dermatophytes; direct contact; infected hairs;
description of cutaneous or dermatomycoses
beneath the skin; caused by fungi that live in _____ or on __________. Infection occurs by direct spore implantation into a puncture wound
soil; vegetation; subcutaneous
can affect a number of organs and tissues. Usually caused by _____ fungi. Inhalation of spores is the route of transmission; infections usually spread from lungs to other parts of the body.
soil; systematic
usually harmless but become pathogenic in an immunocompromised host
opportunistic
called conjugation fungi, sporangium fungi or common mold
Phyla Zygomycota
Molds that have coenocytic hyphae
Phyla Zygomycota
Asexual spore type in phyla zygomycota
sporangiospores
how do zygomycota reproduce sexually?
reproduces sexually by means of zygospores
- called Sac fungi (due to the ________)
• includes molds with septate hyphae and some yeast
• Asexual spores: ___________
• Sexual spores: ___________
ascus; conidiospores; ascospores Phyla Ascomycota
- called club fungi derived from the club shape of the __________
- includes fungi that produce _______
- posses septate hyphae
- Asexual spore type: some produce ___________ (others reproduce by ___________)
- Sexual spore type: ___________
basidium; mushrooms; conidiospores; fragmentation; basidiospores (Basidiomycota)
Produce asexual spores only – rRNA sequencing places most in \_\_\_\_\_\_\_\_\_\_; a few are \_\_\_\_\_\_\_\_\_\_\_ – Penicillium – Candida albicans-- \_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_
(Anamorphs) ascomycota; basidiomycota; cutaneous mycoses
used to produce citric acid (since 1914)
Aspergillus niger
used to produce bread, wine, beer, and genetically modified to produce a variety of proteins (i.e. HBV vaccine)
Saccharomyces cerevisiae
produces the enzyme Cellulase used to digest
plant cell walls to produce a clear fruit juice, etc.
Trichoderma
produces Taxol, an anticancer drug (1967- 1993
the bark of Pacific yew trees was only source)
Taxomyces
kills gypsy moths
Entomophaga
grows on plant roots. Parasitic weevils that eat the roots die
Metarrhizium
foam containing fungi used to kill termites
Paecilomyces fumosoroseus
feeds on other fungi that feed on soybeans
Coniothyrium minitans
_______ (not bacteria) commonly spoil fruits,
grains and vegetables
- little moisture on the unbroken surface
- fruit interiors are too ______ for many bacteria
molds; acidic
Molds spoil jams and jellies
- tend to be acidic and have a high _______
due to sugars
- a ________ layer will keep out oxygen and
deter mold growth
osmolarity; parrafin
Fungi have devastated some tree species
- A fungal blight caused by an __________ killed almost all spreading chestnut trees in the U.S.
- The dutch elm disease has devastated the American elm population
ascomycete
which kingdom are lichens placed into?
fungi
Mutualistic relationship between a green alga (or ___________) and a fungus (usually an ___________)
– Require the mutualistic relationship for each to exist
– Exist where neither an alga or fungus could exist alone
• typically first life forms to colonize newly exposed soil and rock
• found on trees, concrete and rooftops
cyanobacteria; ascomycete
Alga produces and secretes ___________; fungus provides attachment (_________) and protection from __________ (cortex)
carbohydrates; rhizines; desiccation
______ secrete organic acids to chemically weather rock
• Some of the slowest growing organisms on Earth
lichens
what are the three morphological categories of lichens
Fruticose
Foliose
Crustose
lichens that have finger-like projections
fruticose
lichens that are leaf-like
foliose
lichens that are flat
crustose
