FUNGI Flashcards
______ are in the Fungi kingdom.
fungi
They are ___________ and acquire food by _______.
Chemoheterotrophs
Absorption
With the
_______ of yeasts, fungi are ________. Most reproduce with ______ and _______ spores.
exception
multicellular
sexual
asexual
_______ colonies are described as __________structures because they’re composed of the cells involved in
_________ and _________.
Fungal
Vegetative
catabolism
growth
Characteristics of fungi
molds and fleshy fungi
yeast
the body of a mold or fleshy fungus and it can grow to immense proportions.
thallus
long filaments of cells joined together
hyphae (hypha)
Under thallus:
Hyphae, in most molds, containing cross-walls called septa (sing. septum), which divide them into distinct, uninucleate (one-nucleus) cell-like units.
Septate hyphae
hyphae, in most molds, containing ________ called ______ (sing. septum), which divide them into distinct, _________ (one-nucleus) cell-like units
cross-walls
septa
uninucleate
Hyphae, in a few classes of fungi, containing no septa and appear as long, continuous cells with
many nuclei.
Coenocytic (or nonseptate) hyphae
hyphae, in a few classes of fungi, containing __ ______and appear as long, ________cells with many nuclei
no septa
continuous
_______ grow by elongating at the _____.
Hyphae
tips
Each part of a hypha is capable of _______, and when a _______ breaks off, it can elongate to form a _____ hypha.
growth
fragments
new
In the laboratory, fungi are usually grown from fragments
_______ from a fungal ______.
obtained
thallus
(a) Septate hyphae have cross-walls, or septa, dividing the hyphae into cell-like units.
(b) Coenocytic hyphae lack septa.
(c) Hyphae grow by elongating at the tips.
Characteristics of fungal hyphae
portion of a hypha that obtains nutrients
Vegetative hypha
portion concerned with reproduction, so named because it projects above the surface of the
medium on which the fungus is growing
Reproductive (or aerial) hypha
the hyphae grow to form this filamentous mass when environmental conditions are suitable,
which is visible to the unaided eye
mycelium
example of Aerial hyphae
Aspergillus niger
- non-filamentous, unicellular; spherical or oval
- widely distributed; frequently white powdery coating on fruits and leaves
yeast
- capable of facultative anaerobic growth; ferment carbohydrates and produce ethanol (brewed
beverages) and CO2 (leavening bread dough)
yeasts
- can perform aerobic respiration to metabolize carbohydrates into carbon dioxide and water
yeasts
_______ yeasts (such as _________)
Budding
Saccharomyces
In ______, the parent cell forms a ________ (bud) on its outer surface. As the bud elongates, the parent cell’s nucleus _____, and one nucleus _______ into the bud. Cell wall material is then laid down between the bud and parent cell, and the bud eventually breaks away
budding
protuberance
divides
migrates
Some yeasts produce buds that fail to ______ themselves; these buds form a _______ chain of cells called a
__________.
detach
short
pseudohypha
_______ ________attaches to human epithelial cells as a yeast but usually requires
pseudohyphae to invade deeper tissues.
Candida albicans
______ yeasts (such as _______________-)
Fission
Schizosaccharomyces
During ______, the parent cell ________, its nucleus divides,
and____offspring cells evenly divided are produced.
fission
elongates
two
____ dimorphism. Dimorphism in the fungus Mucor indicus depends on ___ concentration. On the agar
surface, Mucor exhibits yeastlike growth, but in the agar
where CO2 from metabolism has accumulated, it is moldlike
fungal
CO2
Dimorphic Fungi
Pathogenic species, exhibit dimorphism – two forms of growth, that is temperature-dependent, either as a
mold (37°C; produce vegetative and aerial hyphae) or as a yeast (25°C; reproduce by budding).
Dimorphism
two forms of growth, that is temperature-dependent, either as a
mold (37°C; produce vegetative and aerial hyphae) or as a yeast (25°C; reproduce by budding)
Filamentous fungi can reproduce asexually by fragmentation of their hyphae. Sexual and asexual
reproduction in fungi occurs by the formation of spores. Spores are formed from aerial hyphae in a number of different ways, depending on the species. Fungal spores can be either asexual or sexual. Fungi are
usually identified by spore type.
LIFE CYCLE
_____ _____ formed by the hyphae of one organism. Such spores are produced through mitosis and
subsequent cell division; there is no fusion of the nuclei of cells. When these spores germinate, they
become organisms that are genetically identical to the parent.
Asexual spores
2 types of asexual pores
- Conidiospore, or conidium
- sporangiospores
-Conidia formed by the fragmentation of a septate hypha into single, slightly thickened cells
▪ e.g.: Coccidioides immitis
Anthroconidia
▪ a unicellular or multicellular spore that is not enclosed in a sac
▪ produced in a chain at the end of a conidiophore
▪ e.g.: Penicillium, Aspergillus
Conidiospore, or conidium
▪ conidia formed from the buds of its parent cell
▪ found in some yeasts, such as C. albicans and Cryptococcus
Blastoconidia
▪ a thick-walled spore formed by rounding and enlargement within a hyphal segment
▪ e.g.: C. albicans
Chlamydoconidia
▪ formed within a sporangium, or sac, at the end of an aerial hypha called a sporangiophore
▪ e.g.: Rhizopus
Sporangiospores
_______ ______ result from the fusion of nuclei from two opposite mating strains of the same species of
fungus and so are made less frequently than asexual spores. Organisms that grow from sexual spores will have genetic characteristics of both parental strains.
sexual spores
- Plasmogamy. A haploid nucleus of a donor cell (+) penetrates the cytoplasm of a recipient cell (-).
- Karyogamy. The (+) and (-) nuclei fuse to form a diploid zygote nucleus.
- Meiosis. The diploid nucleus gives rise to haploid nuclei (sexual spores), some of which may be
genetic recombinants
Three phases
A haploid nucleus of a donor cell (+) penetrates the cytoplasm of a recipient cell (-).
Plasmogamy
The (+) and (-) nuclei fuse to form a diploid zygote nucleus.
Karyogamy
The diploid nucleus gives rise to haploid nuclei (sexual spores), some of which may be
genetic recombinants.
Meiosis
The life cycle of _______, a zygomycete.
Rhizopus
- usu. grow better in an environment with a pH of about 5
- almost all molds are aerobic; most yeasts are facultative anaerobes
- resistant to osmotic pressure; most can grow in relatively high sugar or salt concentrations
- grow on substances with a very low moisture content
- require somewhat less nitrogen
- metabolizes complex carbohydrates, such as lignin
Environmental requirements and nutritional characteristics:
Medically important fungi
Teleomorphs and Anamorphs
fungi that can produce both sexual and asexual spores.
Teleomorphs
▪ or conjugation fungi, are saprophytic molds that have coenocytic hyphae
▪ asexual spores – conidia, chlamydoconidia, sporangiospores
- Zygomycota/Zygomycetes
▪ large sexual spores enclosed in a thick wall called a zygosporangia
▪ this forms when the nuclei of two cells that are morphologically similar to each other fuse
Zygospores
▪ lack mitochondria; don’t have microtubules
▪ obligate intracellular parasites
▪ sexual reproduction has not been observed but probably occurs within the host
▪ chronic diarrhea and keratoconjunctivitis, most notably in AIDS patient
- Microsporidia
The life cycle of ___________, a microsporidian
Encephalitozoon
an emerging opportunistic
infection in immunocompromised patients and the elderly. E. intestinalis causes diarrhea.
Microsporidiosis
▪ or sac fungi, include molds with septate hyphae and some yeasts
▪ asexual spores – conidia
- Ascomycota/Ascomycetes
▪ sexual spores are produced in a saclike structure called an ascus (pl. asci)
▪ this forms when the nuclei of two cells that can be either morphologically similar or
dissimilar fuse
Ascospores
The life cycle of ________, an ascomycete.
Talaromyces
▪ or club fungi, possess septate hyphae
▪ this phylum includes fungi that produce mushrooms
▪ asexual spores – conidia
- Basidiomycota/Basidiomycetes
▪ formed externally on a base pedestal and is club-shaped called a basidium (pl. basidia)
Basidiospores
▪ some ascomycetes (and a few are basidiomycetes) have lost the ability to reproduce sexually
Anamorphs
▪ any fungal infection
▪ generally chronic (long-lasting) infections because fungi grow slowly
Mycosis
- Systemic Mycoses
- Subcutaneous mycoses
- Cutaneous mycoses (dermatomycoses)
- Superficial mycoses
- opportunistic mycoses
Classification according to the degree of tissue involvement and mode of entry into the host:
▪ deep within the body; not restricted to any particular region of the body but can affect a
number of tissues and organs
▪ usu. caused by fungi that live in the soil
▪ spores are transmitted by inhalation; these infections typically begin in the lungs and then
spread to other body tissues
▪ not contagious from animal to human or from human to human
▪ histoplasmosis coccidioidomycosis
systemic mycoses
▪ beneath the skin caused by saprophytic fungi that live in soil and on vegetation
▪ infection occurs by direct implantation of spores or mycelial fragments into a puncture
wound in the skin.
▪ sporotrichosis
Subcutaneous mycoses
▪ fungi that infect only the epidermis, hair, and nails
▪ secrete keratinase, an enzyme that degrades keratin, a protein found in hair, skin, and
nails
Cutaneous mycoses or dermatomycoses
▪ fungal infection localized in surface epidermal cells and along hair shafts
superficial mycoses
▪ generally harmless in its normal habitat but can become pathogenic in a host who is
seriously debilitated or traumatized, who is under treatment with broad-spectrum
antibiotics, whose immune system is suppressed by drugs or by an immune disorder, or
who has a lung disease
▪ Pneumocystis (pneumocystis pneumonia, PCP), Stachybotrys, Rhizopus and Mucor
(mucormycosis), Aspergillus (aspergillosis), Cryptococcus, Penicillium, C. albicans (yeast
infection, or candidiasis)
opportunistic mycoses
Fungi are beneficial.
-food chain
-symbiosis
-fungi-farming ants
-human use fungi for food and produce foods and drugs
-used in biotechnology
-used as biological control of pests
________ decompose
the hard parts of plants which animals can’t digest.
Cellulases
________, the symbiotic fungi, help plant roots absorb minerals and water from soil.
Myccorhizae
Fungi-farming ants ______ fungi that break down cellulose and lignin from plants, providing _______ that the ants can then digest.
cultivate
glucose
Humans use fungi for food (______) and to produce foods (bread; ______ _______ – citric acid) and drugs (alcohol and _______; _______ – anticancer drug taxol).
mushrooms
Aspergillus niger
Alcohol
Taxomyces
___________ cerevisiae is used to make
bread and wine; genetically modified to produce a variety of proteins, including ________
vaccine
Sacchromyces
hepatitis B
__________ is used produce the enzyme cellulase, which is used to _______ plant cell walls to produce a clear______juice.
Trichoderma
remove
fruit
___________ minitans feeds on fungi that destroy soybeans and other bean crops.
Coniothyrium
A foam filled with _______ fumosoroseus kill termites hiding
inside tree trunks and other hard-to-reach places
Paecilomyces
fungi can have undesirable effects.
- Mold spoilage of fruits, grains, and vegetables is more common than bacterial spoilage of these
products. - Many fungi cause diseases plants.
- Of the more than 100,000 species of fungi, only about 200 are pathogenic to humans and animals.
However, over the last 10 years, the incidence of serious fungal infections has been increasing
occurring in health care settings and in people with compromised immune systems.
