Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology Exam 3 Exam > Fungi 1 > Flashcards

Fungi 1 Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What does it mean when we say fungi are heterotrophs that feed by absorption? (Fungal classification)

A

-Cannot make their own food
-Do not ingest their food
-They secrete hydrolytic digestive enzymes into their surroundings
-These enzymes digest organic substrates
-THe fungal cells then absorb the resulting soluble organic molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does it mean when we say that fungi are decomposers? (Ecological roles)

A

-Break down and absorb nutrients from the environment
-Dead plant materials
-Animal corpses
-Wastes of living organisms
-Without the decomposers, crucial elements would remain tied up in organic matter; life as we know it would not be possible (C,N,P, and S would not be available for the use of other organisms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does it mean when we say that some fungi are parasites? (Ecological roles)

A

Absorb nutrients from the cells of living hosts but provide no benefits in return

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are Rusts?

A

-Plant disease caused by parasitic fungi (order: Pucciniales)
-Spores germinate and invade plant cell
-Cause plant deformities
-Are among the most harmful pathogens to agriculture, horticulture, and forestry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are Smuts?

A

-Plant diseases primarily affecting grasses (corn, wheat, sugarcane, and sorghum) by parasitic fungi (Class: Ustilaginomycetes)
-Powdery fungal spores accumulate within blisters in plant tissues
-Eaten as a delicacy in Mexico (Huitlacoche)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are Blights?

A

Plant diseases caused by various parasitic fungi resulting in chlorosis, browning, then the death of plant tissues
-Examples include: Potato blight, Tomato blight, American chestnut blight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is Ergot?

A

Plant disease caused by parasitic fungus (Genus: Claviceps) growing on grasses and cereals
-Spore germinates in flowering grass/cereal; mimics a pollen grain growing into plant ovary
-Resulting mycelium resembles seed grain
-Produces hallucinogenic compounds
(St. Anthony’s fire, Salem Witch trials, “Great fear” aka French Revolution)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is athlete’s foot (Tinea pedis) and Ringworm?

A

Fungal infection of the skin by various fungi (Trichophyton, Epidermophyton, Microsporum)
-Transmission: direct contact with infected skin, shower, and locker room floors, etc.
-Causes itching, scaling, redness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are fungal mutualists?

A

Symbiotic relationship between a fungus and another organism wherein both members benefit
(EX: Leaf-cutting Ants, Ruminants, Lichens, Plants)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Fungal mutualists Leaf-cutting Ants

A

Ants cut leaf sections from suitable plants
Carry leaf sections back to the nest
Feed the leaves to fungal “farms”
Fungus produces specialized hyphae tips rich in proteins and carbohydrates
Fungi cannot survive without the ants
Ants depend on the fungi for food and detoxification of plant defensive compoinds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Fungal mutualists: Ruminants

A

The rumen is a large stomach chamber that serves as a fermentation tank
Contains bacteria, protozoa, and fungi (Phylum Chytrids)
Symbionts digest cellulosic plant material and release nutrients beneficial to the cow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Fungal mutualists: Lichens

A

Symbiotic relationship between a phototroph (cyanobacteria or green algae) and a fungus
Pioneer organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are plants?

A

All plant species studied to date appear to cultivate fungal symbionts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Type of relationships between plants and fungus?

A

Endophytes
Mycorrhizae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is an Endophytes relationship?

A

Fungi (Order: Ascomycetes) or bacteria that live inside the plant
Produce toxins that deter herbivores
Increase plant tolerance to heat, drought
Protect plant from pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a Mycorrhizae relationship?

A

Mutually beneficial relationships between fungi and plant roots
Fungal partners improve solubilization and delivery of minerals to the plant
Plant partners provide organic nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the two types of Mycorrhizae associations?

A

Ectomycorrhizal associations
Arbuscular mycorrhizal associations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is an Ectomycorrhizal association?

A

Fungi (Phyla: Basidiomycetes, Ascomycetes) form sheaths of hyphae over the woody plant cell surface and grow into the extracellular spaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is an Arbuscular mycorrhizal association?

A

Fungi (Phylum: Glomeromycetes) extended branching hyphae through the plant cell wall and into tubes formed by the invagination of the plant cell plasma membrane.
Fungus forms the Haustorium: the structure that protrudes into the cell; allows the fungus to extract nutrients from, or to exchange nutrients with, the plant host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Edible mushrooms

A

Buttons, morels, truffles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Ripened cheeses

A

Blue cheese, Camembert, Bri

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Food source

A

Miso, tempeh, soy sauce, Baker’s and brewer’s yeast

23
Q

Medicines: Antibiotics

A

Produced by soil bacteria and fungi to gain an advantage when competing for food, water, or other limited resources
Kill or inhibit the growth of bacteria
(EX: Penicillin and Cephalosporins)

24
Q

Medicines: Immune suppressants

A

Used to inhibit organ rejection (e.g. Cyclosporin A)

25
Q

Medicines: Statins

A

Used to lower low density lipoproteins (e.g. Lovastatin and Squalestatin)

26
Q

Medicines: Ergot alkaloids

A

Used to lower blood pressure

27
Q

Yeast

A

Single-celled fungal form
-Require moist environments (plant sap, animal tissues) with a ready supply of soluble nutrients (sugars and amino acids)

28
Q

Filamentous

A

Multicellular fungal form
-Most prevalent form of fungi
-Typically form a network of tiny filaments

29
Q

Hypha (plural: hyphae)

A

Each of the fungal filaments that make up the body of a fungus
-Consist of tubular cell walls surrounding the plasma membrane and cytoplasm of the fungal cells

30
Q

Mycelium (plural = mycelia)

A

An interwoven mass of hyphae
-Infiltrates the material on which the fungus feeds
-maximizes surface-to-volume ratio to make feeding very efficient

31
Q

Basidiocarp

A

The above groud spore-bearing fruiting body of a fungus (“mushroom”)
-The mushroom and its subterranean mycelium are a continuous network of hyphae

32
Q

Septum (plural: septa)

A

Cross-walls that divide hyphae into cells
-Typically fungal septa have pores large enough to allow ribosomes, mitochondria, and nuclei to flow from cell to cell

33
Q

Coenocytic fungi

A

Fungi that lack septa
-Consist of a continuous cytoplasmic mass having hundreds or thousands of nuclei
-Result from the repeated division of nuclei without cytokinesis

34
Q

Spore

A

Reproductive structure
-adapted for dispersal and survival
-may be generated asexually or sexually
-germinate in moist, nutrient-rich places, to produce a new mycelium
-some species can produce and release billions of spores in a single dispersal event

35
Q

Pheromones

A

Sexual signaling molecules
-Bind to cellular receptors
-Trigger the growth of hyphae toward the source
-Result in cellular fusion between the two compatible partners

36
Q

Plasmogamy

A

The sexual union (fusing) or two haploids (n) parent mycelia
-produce heterokaryotic cells: genetically different nuclei co-existing in the same cell
-not diploid (2n) because the genetic material from each parent is maintained in separate nuclei (Described as n + n)

37
Q

Karygamy

A

Fusing of the two nuclei on a heterokaryotic cell
-May occur hours, days, or centuries after plasmogamy
-Produces a temporary diploid cell (zygote)

38
Q

Zygote

A

A diploid cell resulting from the fusion of two haploid nuclei

39
Q

Reproduction in filamentous fungi

A

Muclei of fungal hyphae are haploid (n)

40
Q

When is a diploid formed?

A

Temporarily during sexual reporudction

41
Q

Whether by sexual or asexual means, most filamentous propagate by

A

Producing spores

42
Q

Generalized Sexual reproduction Cycle:

A
  1. Pheromones secreted by two different mating types cause hyphae to grow close
    together
  2. Plasmogamy occurs, producing heterokaryotic cells (typically diplokaryotic)
  3. Karyogamy occurs, producing a temporary zygote (diploid)
  4. Meiosis occurs creating four haploid nuclei from the diploid zygote
  5. Spores are created when hard walls form around each haploid nucleus; the
    durable meiospores are then released upon maturity and dispersed by the wind
  6. Germination occurs when the spores land in a hospitable environment (moist
    and nutrient-rich), resulting in new haploid hyphae that grow into a new
    mycelium
43
Q

Reproduction in yeast: Asexual process (“budding”)

A
  1. A diploid parent cell produces a small protuberance that grows to form
    a bud
  2. Mitosis occurs, duplicating the parental nucleus, and one nucleus
    migrates into the developing bud
  3. The bud continues to grow until it separates from the mother, forming a
    new cell
44
Q

Reproduction in yeast: Sexual process

A
  1. A diploid cell can undergo meiosis to create Mat a and Mat α haploid
    cells
  2. Two haploid cells of different mating types secrete pheromones
  3. Reception of the opposite pheromone causes cells to change shape and
    enter the Schmoo stage
  4. Cells come together; cytoplasms fuse and then nuclei fuse to form a
    diploid zygote
  5. The cell then reenters the cell division cycle and gives rise to its first
    diploid bud
  6. The bud matures into a fully formed daughter cell and separates from
    the mother
    Note: the diploid zygote can undergo sporulation, but only under high-stress
    conditions (e.g. nutrient starvation); these spores can later germinate to
    produce Mat a and Mat α haploid cells
45
Q

DNA analysis: Clade

A

A group of organisms that consist of a common ancestor and all its lineal descendants

46
Q

DNA analysis: Opisthokonts

A

Meaning: posterior flagella
Common ancestor: unicellular flagellated ancestor
Lineal descendants: Animals, Flagellated protists, Fungi

47
Q

Fossil record

A

Fungi may have colonized land before plants
-probably existed along with cyanobacteria and algae as among the first terrestrial colonizers
 405 million year old plant fossils show evidence of mycorrhizal
relationships
 The earliest land plants lacked roots, limiting their ability to extract
nutrients from the soil
 Fungal partners likely helped transfer soil nutrients to the early land
plants via extensive mycelia

48
Q

Chytrids

A

Phylum: Chytridiomycota
Primarily aquatic (lakes, moist soil, and marine)
One of the earliest fungi to diverge from the protists
Possess flagellated spores (Zoospores)
The only fungi with true motility
Reminiscent of protist ancestry
During sexual reproduction they produce a globular fruiting body that forms
multicellular, branched hyphae
The name, Chytrid, comes from this globular fruiting body (chytridion = “little
pot”)
Ecological roles
 Most are decomposers
 Some are mutualists (e.g. ruminants)
 Some are parasites
o 1999: Batrachochytrium dendrobatidis described
o Infects the skin of amphibians
o Has resulted in devastating population declines and species
extinctions
o “Chytridiomycosis”

49
Q

Zygomycetes

A

Phylum: Zygomycota
Coenocytic hyphae
Form characteristic Zygosporangia
Formed through the fusion (“zygos”) of two gametangia (specialized
hyphal strands)
The name of this group, Zygomycota, refers to this structure, zygosporangium,
formed during sexual reproduction
Form characteristic zygosporangia
Thick-walled structure
Desiccation- and chemically-resistant
Germinates into a sporangium on a short stalk
Roles
 Primarily terrestrial living in soil or on decaying plant or animal material
 Includes many of the fast-growing molds that cause breads and fruits to
rot
 Primarily terrestrial living in soil or on decaying plant or animal material
 Includes species (Pilobolus sp.) that can aim and shoot sporangia toward
light
o Grow in animal dung
o Clear subsporangial vesicle acts as a lens to heat up and direct
the fruiting structure toward light
o Explodes to spread spores toward sun-drenched grass, away
from dung
 Can cause disease in humans and animals
o Allergies (Sinusitis)
o Skin and GI infections, but only in immunocompromised hosts

50
Q

Glomeromycetes

A

Phylum: GlomeromycotaGlomus (latin): “ball”
Refers to its characteristically shaped Glomerospores
Newly defined phylum
Previously assigned to Zygomycota
Reclassified based on DNA sequence
Only observed to replicate asexually, but appears to have the genes for meiosis, suggesting an as yet unobserved sexual reproductive mechanism
Nearly all form arbuscular mycorrhizae with plants
 Fungus mycelia extend into soil to dissolve and uptake minerals (PO4,
Zn, Cu, etc.)
o Nourishes plant root cells via haustoria
 Plant provides sugars and amino acids
Recent studies regarding mycorrhizal associations
 >80% of terrestrial plants have a mycorrhizal relationship with
Glomeromycetes
 Most Glomeromycetes are dependent on the plant- fugus relationship;
unable to grow independently
Recent studies regarding mycorrhizal associations
 Many plants depend on the mycorrhizal association and fail to thrive
without the fungal symbiont

51
Q

Ascomyetes

A

 Phylum: Ascomycota
 Range in size from unicellular yeasts and filamentous molds to elaborate cup
fungi and morels
 Include:
o Saccharomyces species
o Cup fungus
o Morel
o Penicillium species
o Aspergillus species
 Reproduction
 Asexual reproduction is the dominant form of propagation
o Spores (conidia) form on the ends of specialized hyphae
(conidiophores)
 Sexual reproduction
o The heterokaryotic hyphae that result from plasmogamy
produce many dikaryotic asci
o The heterokaryotic hyphae that result from plasmogamy
produce many dikaryotic asci
o Karyogamy occurs within each ascus producing a diploid nucleus
o Each nucleus divides by meiosis yielding four haploid nuclei
o Each haploid nucleus divides once by mitosis, yielding eight
nuclei; cell walls develop around the nuclei forming ascospores
o The ascocarp (a collection of asci) forms and, when fully
developed, discharges the ascospores forcibly
 Named for the characteristic ascus structure formed during sexual reproduction
 Roles
 Important decomposers of plant material
 Includes edible species (morels, truffles, and beneficial yeasts)
 Some form beneficial Ectomycorrhizal associations with plants
 Some serve as the fungal partner in lichens
 Includes many animal and plant pathogens
 Aspergillus -> Aflatoxins (toxin in peanuts, hay, & grains)

52
Q

Basidiomycetes

A

 Phylum: Basidiomycota
 Reproduction
 Primarily sexual reproduction
o After plasmogamy, the dikaryotic mycelium grows faster than,
and ultimately crowds out, the haploid parental mycelia
o Environmental cues (rain, temperature changes, etc.) induce the
dikaryotic mycelium to form compact masses that develop into
basidiocarps
o Environmental cues (rain, temperature changes, etc.) induce the
dikaryotic mycelium to form compact masses that develop into
basidiocarps
o Karyogamy in each basidium produces a diploid nucleus, which
undergoes meiosis with each diploid nucleus yielding four
haploid nuclei, each of which develops into a basidiospore
o When mature, the basidiospores are ejected and dispersed by
the wind
o When mature, the basidiospores are ejected and dispersed by
the wind
o Basidiospores germinate in suitable environments to form
haploid mycelia
 Includes the mushrooms, puffballs, and shelf fungi
 Some are edible
 Some are deadly
 Some are hallucinogenic
 Includes many of the rusts and smuts
 Cause billions of dollars in damage to crop plants
 Responsible for Fairy rings
 Once the fruiting bodies are constructed, mushrooms rapidly absorb
water & “pop” up over night
 Mycelium grows at a rate of ~30 cm/year
 Some giant fairy rings are centuries old
 Often produce rings of enhanced grass growth
 Important decomposers of wood
 Wood is a complex mixture of cellulose, hemicelluloses, and lignin
 Lignin serves as a cement, a stiffening agent, and a barrier to enzymatic
degradation
 Makes wood recalcitrant to decomposition
 Basidiomycetes are one of the few organisms that can completely
mineralize wood, including the lignin component

53
Q

Deuteromysetes (Imperfect fungi)

A

 Note: Classical taxonomy classifies fungi based on structures formed during
sexual reproduction
 Chytridiomycota: chytridion = “little pot” Contains its zoospores
 Zygomycota = zygosporangium holds its sporangiospores
 Ascomycota = ascus holds its ascospores
 Basidiomycota = basidium holds its basiospores
 Deuteromycetes are those fungi that do not reproduce sexually and have no
sexual reproductive features
 …or, at least, contains those whose sexual reproduction has not yet
been observed.
 Deuteromycetes is not a true phylum
 Only a temporary holding group
 Probably includes members of each identified fungal phylum…and
maybe

Microbiology Exam 3 Exam (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions