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Both bacteria and fungi are decomposers. What characteristics do these two groups share that allow them to function in this ecological role you may want to use information from 21.2

CH 21 PROTISTS AND FUNGI

21.4 Fungi

What Are Fungi

 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

 Hyphae  Long, slender branching filaments  1-2 nuclei  Openings in cross walls allow for cytoplasm movement.

 Fruiting body  Reproductive structure of the fungus  What we call the mushroom  Mycelium  Mass of branching hyphae below the soil that fruiting body grows from  Often has many mushrooms.

Reproduction

 Asexually  Releasing spores that travel through air and water  Breaking off a hypha or budding off a cell.

 Most can also use sexual reproduction.

 One mating type is called “+” (plus) and the other “–” (minus)  Think male and female for people  Hyphae of opposite mating types fuse together.

 The + and – nuclei form pairs that divide  Many paired nuclei fuse to form diploid zygotes within zygospore.

 Zygospore germinates and a sporangium emerges  Sporangium reproduces asexually, releasing haploid spores produced by meiosis.

 Parasitic fungi cause diseases that threaten food crops  Others affect animals  Athletes foot  Yeast infections

Lichens

 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

 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.

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By what percent is the mycorrhizae lemon tree taller than the non mycorrhizae lemon tree Make a generalization about the growth rate of plants with mycorrhizae 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

Structure of Bread Mold

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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.

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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