Transcript Ch 21 Protists and Fungi

1.
Both bacteria and fungi are decomposers. What
characteristics do these two groups share that
allow them to function in this ecological roleyou may want to use information from 21.2
CH 21 PROTISTS AND FUNGI
21.4 Fungi
What Are Fungi
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Heterotrophic eukaryotes with cell walls that
contain chitin
Produce enzymes that digest food outside their
bodies
Absorb the small molecules released by the
enzymes
Can be decomposer or parasite.
Structure and Function
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Hyphae
 Long,
slender branching filaments
 1-2 nuclei
 Openings in cross walls allow for cytoplasm movement.
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Fruiting body
 Reproductive
structure of the fungus
 What we call the mushroom
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Mycelium
 Mass
of branching hyphae below the soil that fruiting
body grows from
 Often has many mushrooms.
Reproduction
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Asexually
 Releasing
spores that travel through air and water
 Breaking off a hypha or budding off a cell.
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Most can also use sexual reproduction.
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One mating type is called “+” (plus) and the other
“–” (minus)
 Think
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male and female for people
Hyphae of opposite mating types fuse together.
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The + and – nuclei form pairs that divide
Many paired nuclei fuse to form diploid zygotes
within zygospore.
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Zygospore germinates and a sporangium emerges
Sporangium reproduces asexually, releasing haploid
spores produced by meiosis.
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Parasitic fungi cause diseases that threaten food
crops
Others affect animals
 Athletes foot
 Yeast
infections
Lichens
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Mutualistic relationship between fungus and a
photosynthetic organism (green alga or
cyanobacterium)
Grow where few other organisms can
Green algae or cyanobacteria provide energy,
fungus provides water and minerals and structure
Often pioneer species.
Mycorrhizae
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Mutualistic relationships with fungi and plant roots
Hyphae collect water and minerals
Also release enzymes that free nutrients in the soil
Plant roots provide energy
80 to 90 percent of all plant species form this
relationship.
By what percent is the mycorrhizae lemon tree
taller than the non mycorrhizae lemon tree
2.
Make a generalization about the growth rate of
plants with mycorrhizae
3.
A citrus grower began using sterilized
soil for repotting lemon trees with the goal of
reducing disease.
But many of the trees
are dying in the new
soil. Form a
hypothesis to explain
this observation
1.
Structure of Bread Mold
1.
2.
3.
Touch the sticky side of a 2 cm piece of
transparent tap to the black fussy area of a bread
mold
Gently stick the tape to a glass slide. Observe the
slide under the microscope. Sketch your
observations.
Wash you slide with soap and water and return
the slide. Be sure to wash YOUR hands as well.
1.
2.
3.
Observe Describe the structures you observed in
the bread mold
Form a Hypothesis What do you think the
function of the round structures is? Why might it
be advantageous for a single mass of bread mold
to produce so many of the round structures
Infer How do your observation help explain why
molds appear on foods even in very clean
kitchens