Download FUNGI

EXPLORING LIFE
EXERCISE 3:
FUNGI
Exercise 3: Fungi
Workbook Contents
Corresponding Section on CD
Vocabulary
Key Concepts
Introduction
1. Introduction
General Biology of Fungi
2. General Biology of the Fungi
Classification, Structures, Growth and Reproduction
2A. Classification
2B. Structure
2C. Growth and Reproduction
The Zygomycota
3. The Zygomycota
The Ascomycota
General Features
Life Cycle
4. The Ascomycetes
4A. General Features
4B. Life Cycle
The Basidiomycota
General Features
Dikaryotic Cell Structure
Reproductive Structures
5. The Basidiomycetes
5A. General Features
5B. Dikaryotic Cell Structure
5C. Reproductive Structures
The Deuteromycota
General Features
Parasexuality
6. The Deuteromycetes
6A. General Features
6B. Parasexuality
Fungal Associations
Lichens
Other Associations
7. Fungal Associations
7A. Lichens
7B. Mycorrhizal and Endophytic
Associations
Summary & Review
Vocabulary Review
Vocabulary
Antheridium - Male reproductive structure
Apothecium - Cup-shaped ascoma
Arbuscules - Highly branched hyphae inside plant cells in endomycorrhizal associations
Ascogonium - Female reproductive structure in the ascomycetes
Ascoma - Spore producing structure in the ascomycetes
Ascomata - Plural of ascoma
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Ascomycetes - One of the three evolutionarily distinct divisions of fungi. The ascomycetes are characterized
by the formation of multinucleated spores called conidia and by the formation of croziers and an ascus
in sexual reproduction.
Ascus - The structure that forms ascospores in the ascomycetes
Aseptate - Without septae, i.e. cross walls
Basidia - Club-shaped structures found on the gills on the underside of the pileus
Basidiomata - Spore-producing structures of the basidiomycetes
Basidium - Singular of basidia
Basidiomycetes - One of the three divisions of fungi; characterized by the formation of basidia during sexual
reproduction.
Cleistothecium - An ascoma without an opening
Coenocytic - Having many nuclei in a common cytoplasm
Conidia - Multinucleated spores, produced by the ascomycetes
Crozier - A hook-shaped structure produced in an ascoma. Nuclei in the central cell of the hook fuse to form the
zygote in the ascomycetes.
Deuteromycetes - An artificial grouping of fungi that do not reproduce sexually. Most members of this group
are derived from the ascomycetes, though some doubtless come from the basidiomycetes and
zygomycetes.
Ectomycorrhizal - A fungal association between zygomycetes and plant roots in which the fungus does not
penetrate the plant's cells
Endophytic - Fungi that live in plant stems and leaves
Endomycorrhizal - Fungi that live inside plant root cells, usually in cortical cells
Fungi - One of the four kingdoms of eukaryotes. Members of this kingdom are characterized by a zygotic life
cycle (the zygote is the only diploid cell in the life cycle), cell walls made of chitin, a body composed of
hyphae, and a lack of histological differentiation.
Fungi Imperfecti - Deuteromycetes
Heterokaryon - A vegetative hyphae containing nuclei from more than one individual
Heterokaryotic - Hetero refers to different; and karyo refers to the nuclei. Heterokaryotic means that there are
nuclei from different individuals in the same hyphae.
Homothallic - Refers to species in which individuals can mate with themselves
Hyphae - Thin filaments of a fungus that form its body or mycelium
Isogamous - Iso implies the same and gamous refers to gametes. In isogamous species the gametes are the same
size and shape, thus individuals are not male or female but are referred to as being + or -.
Karyogamy - The fusion of nuclei
Lichen - An association between either green algae or cyanobacteria and an ascomycete or rarely a
basidiomycete
Monokaryotic - Having one nucleus per cell, mono = one; karyo = nucleus
Mycelium - A mass of hyphae comprising one individual
Mycorrhizal - Fungi that live in association with plant roots
Perithecium - A flask-shaped ascoma
Pileus - The cap of a mushroom
Plasmogamy - The fusion of cytoplasms from different individuals
Rhizoids - Hyphae that anchor the fungus to its substrate
Septum - A cross wall dividing hyphae into cells
Sporangiophore - The hyphae that support a sporangium
Sporangium - Spore-producing structure
Sterigmata - The projection of a basidium from which spores are released
Stipe - The stalk supporting a pileus
Stolons - Arching hyphae found between sporangiophores in the zygomycetes
Trichogyne - The tube that grows from the ascogonium to the antheridium in the ascomycetes. The male nuclei
move through this tube to enter the ascogonium.
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Vesicles - Fungal swellings inside plant cells in endomycorrhizal associations. Vesicles are believed to be used
by the fungus for storage of food.
Zygomycetes - One of the three divisions of fungi; characterized by the production of zygospores
Zygospore - A thick-walled spore that develops directly from a zygote. The spore is a resistant resting stage
and is contained within a zygosporangium.
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Key Concepts
Introduction
1. The fungi are eukaryotic / prokaryotic and generally multicellular / unicellular.
2. Describe two ecologically important roles (+ and -) of fungi:
3. What portions of fungi remain alive and respiring?
4. List three economically important roles (+ and -) of fungi:
General Biology of Fungi
Classification, Structures, Growth and Reproduction
5. Draw a line between the term and its definition
aseptate
a. having a thread-like structure; used to describe the bodies of fungi
coenocytic
b. bodies of fungi, consisting of masses of filaments
filamentous
c. filaments that compose the bodies of fungi
hyphae
d. wall that divides a hyphae
mycelia
e. said of hyphae with septa; fungus then has definite cells
septate
f. said of hyphae without septa; fungus then has no definite cells
septum
g. having many nuclei within a common cytoplasm
5. Mark an “X” in the boxes that correspond to characteristics found within each group. Color in those boxes that do not apply.
Characteristic
Fungi Plants Animals Characteristic
Fungi Plants Animals
Cell Division
Cell Walls
of cellulose
nuclear membrane breaks down
of chitin
nuclear membrane does not break down
Capable of movement
lack centrioles; few histone proteins
Have motile gametes
have centrioles and histone proteins
Acquire nutrition through:
capable of sexual & asexual reproduction
Cells that undergo meiosis are
ingestion
external digestion/absorption
diploid adult cells
photosynthesis
zygotes; only diploid life cycle stage
Circulation
Organism body
heart & vessels
little or no variation into tissues and organs
cytoplasmic streaming
differentiation of cells into tissues & organs
Principle storage product
Other characteristics; environmental contact
glycogen
definite size & shape; cells buffered
starch
indefinite size & shape; cells near
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The Fungi
Classification, Structures, Growth and Reproduction (continued)
6. Describe the unique structure of the fungi and what it allows them to do within their environment:
How are we making use of this uniqueness?
The Zygomycota
7. Zygospore = thick / thin walled structure produced during the asexual / sexual part of the life cycle.
Asexual / sexual reproduction occurs only during times of stress.
Label the steps of this process, and the 2n (diploid) state, on the diagram below. Be sure to use the terms
dormancy, fusion, hyphae, mature, meiosis, nuclear fusion, nuclei, sporangium, spores, zygospore.
8. Pause the movie on the diagram of the zygomycete life cycle to complete the exercise below:
Label this diagram with these terms: +mating type, -mating type, rhizoid, sporangium, sporangiophore,
spores, stolon. This diagram represents asexual / sexual reproduction.
9. Using the “Key Words” function from the Main Menu, finish the following definitions:
Isogamous = males and females have same / unequal sized gametes.
Homothallic = species that fertilize another individual / themselves.
Heterothallic = species that fertilize another individual / themselves.
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Key Concepts
The Ascomycota
General Features
10. List some of the economic roles of members of this group:
Positive:
Negative:
11. Yeasts are classified as fungi because some have
under certain conditions while others have
reproductive structures like those of the ascomycota / basidiomycota / deuteromycota / zygomycota.
12. Mark an “X” in the boxes that correspond to characteristics found within each group.
Asexual reproductive structures
Ascomycota Zygomycota
sporangia form many spores
spores are multinucleated; called conidia
spores are uninucleated
conidiophores develop while conditions are favorable
Life Cycle - It might be helpful to pause the movie at various points to label the following diagram.
13. Label the diagram below with descriptions of each step, including what is happening to the nuclei and all
n/2n states, and these terms: antheridium, ascogonium, ascospore, ascoma, ascus, conidia, conidiophore,
crozier, dikaryotic, diploid, germinating, haploid, hyphae, karogamy, meiotic, migrate, mitosis, nuclei,
plasmogamy, sterile, trichogyne, “zygote”. This diagram represents asexual / sexual reproduction.
It occurs when conditions are not stressful / stressful.
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The Fungi
The Basidiomycota
General Features
14. What are some common example organisms from this group?
15. What are their two most important ecological roles? a)
b)
16. Draw and label a picture of two typical adjacent basidiomycete cells. Use the terms membrane cap, pore,
septum. Which of these structures is unique to basidiomycetes?
Dikaryotic Cell Structure
17. Label the structures and processes of basidiomycete reproduction. Be sure to describe what is happening to
the nuclei and use the terms: basidioma, basidiophore, basidium, basidiospore, monokaryotic, dikaryotic,
plasmogamy, karyogamy, clamp connection. What is so important about clamp connections?
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Key Concepts
The Basidiomycota (continued)
18. Label the following basidiomycete life cycle diagram. Be sure to distinguish which part of the cycle is
sexual and which part is asexual.
Reproductive Structures
19. Draw and label a basidiomata (side and top views). Include the terms appressed hyphae, gills, pileus, stipe.
Then draw and label an enlargement showing a basidium and sterigmata:
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The Fungi
The Deuteromycota
General Features
20. The deuteromycetes are heterogeneous / homogeneous, made up of ascomycetes / basidiomycetes /
zygomycetes, grouped together because they lack asexual / sexual reproduction.
List and describe some of the important deuteromycetes:
Parasexuality
21. Heterokaryotic = hyphae with nuclei from one / more than one individual of different / the same
species in which both / only one / neither nucleus is genetically active. What is the difference between
this and dikaryotic?
22. How do deuteromycetes ensure genetic variation?
Briefly describe the process:
Fungal Associations
Lichens
23. These organisms are an association between a fungus and an
What is the role of the fungus in this relationship?
24. What are the three shapes?
25. Draw and label a cross section of a typical lichen.
26. What are two ecological roles of lichens?
Other Associations
27. With what other organisms (and where) do fungi form associations?
28. What are the fungi that form associations with roots?
What is the role of the fungus in this relationship?
29. What do endophytic fungi do for the plants?
What do endophytic fungi do to herbivores?
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or a
Summary & Review
1. What two structures do all fungi share?
and
.
2. Fill in the following chart and then use the chart to answer the questions below:
Characteristics
Ascomycota
Basidiomycota
Zygomycota
cells walls made of
septa present?
distinguishing
features (if any)
asexual structure(s)/
processes
sexual structure(s)/
processes
time in diploid state
representatives
a) What are the features all fungi share that set them apart from other organisms?
b) What characteristics do fungi lack that separate them from other organisms?
c) Do fungi have motile cells in any part of their life cycle?
Do other organisms?
d) How do all fungi acquire nutrients?
e) Look up the word “saprophytic.” How does it apply to fungi?
f) What structures/processes seem to be unique to each of the groups?
Ascomycota:
Basidiomycota:
Zygomycota:
g) Why are the Deuteromycota not included in the table above?
h) Go to movie #1, “The Five Kingdoms,” and review the various life cycles and modes of acquiring nutrition.
What type of life cycle do fungi exhibit?
How do fungi acquire their nutrition?
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Fungi
2. Describe the ecological importance, both positive and negative, of each of the groups. Use specific examples
where you can.
a) Ascomycota:
b) Basidiomycota:
c) Zygomycota:
d) Deuteromycota:
3. Describe the economic importance, both positive and negative, of each of the groups. Use specific examples
where you can.
a) Ascomycota:
b) Basidiomycota:
c) Zygomycota:
d) Deuteromycota:
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Vocabulary Review
Using the following definitions, complete the crossword. Key definitions to learn are marked (*). Most definitions can be found in the
“Key Words” section of the movie. Definitions for prefixes begin with “of the”.
Across
Down
5. cells with two, unfused nuclei
1. of the association where the fungus lives within a plant’s cells
6. of the association where the fungus does not penetrate a plant’s cells
2. male reproductive structure
*8. association between a green algae or cyanobacteria and a fungus
3. spore-producing structures of the basidiomycetes
*9. mass of hyphae comprising an individual fungus
4. the opening perforating the cross wall of septate hyphae
12. person who studies fungi
6. fungi that live in plant stems and leaves
*13. of the division of fungi characterized by the formation of basidia
7. tube growing from ascogonium to antheridium among ascomycetes
*14. of the artificial grouping of fungi that do not reproduce sexually
10. having many nuclei in a common cytoplasm
15. gamete-producing structures
11. having nuclei from different individuals in the same hypha
*19. fungi that live in association with plant roots
12. parenthesis-shaped structure to either side of basidiomycete pores
23. cell formed by fusion of two gametes
16. thick-walled structure formed when two zygomycete hyphae fuse
24. one of the other, non-fungal organisms in a lichen
17. projection of a basidium from which spores are released
25. having half the number of chromosomes as a somatic cell
18. fusion of nuclei
27. multinucleated spores produced by the ascomycetes
20. a chemical produced by some fungi which can cause liver cancer
28. process of fusion, recombination & resegregation of chromosomes
21. without septae, i.e., cross walls
29. fusion of cytoplasm from different individuals
22. thin filaments that form the body, or mycelium, of a fungus
31. the basidiomycete form of cell division (two words)
26. division of fungi characterized by the formation of a zygospore
33. an asexual reproductive cell
*27. multinucleated spores produced by the ascoma
35. division of fungi that forms conidia, croziers and asci
30. spore-producing structures
36. substance that forms the cell walls of fungi
32. ascoma without an opening
37. spore-producing structure in the ascomycetes
33. cross walls dividing hyphae into cells
38. hooked-shaped structures produced in the ascomycetes
34. fungal association between zygomycetes and plant roots in which
the fungus does not penetrate the plant’s cells
40. one of the four kingdoms of eukaryotes, characterized by a zygotic life cycle, cell
walls of chitin and a body composed of hyphae
39. stalk supporting a pileus
41. to break down a dead organism
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