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Fungi Chapter 31.

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Presentation on theme: "Fungi Chapter 31."— Presentation transcript:

1 Fungi Chapter 31

2 Fungi

3 Fungi

4 Fungi

5 Fungi More closely related to animals than plants Unicellular
Most are multi-cellular Tropics to tundra Aquatics to terrestrial Airborne spores Yeast in breads & beer


7 Fungi Decomposers Recycle nutrients
Help roots of plants absorb nutrients Disease causing (plants and animals) Treatment difficult

8 Body structure Hyphae Tiny filaments Composed of cytoplasm
Surrounded by plasma membrane & cell wall Cell wall made of chitin Septa Cross-walls that separate cells of hyphae

9 Hyphae

10 Cell wall Cell wall Nuclei Pore Septum Nuclei (a) Septate hypha
Fig. 31-3 Cell wall Cell wall Nuclei Pore Septum Nuclei Figure 31.3 Two forms of hyphae (a) Septate hypha (b) Coenocytic hypha

11 Body structure Mycelium: Mass of connected hyphae
Surrounds & infiltrates material Maximizes contact with material Grows rapidly Grows underground so not visible


13 Figure A fairy ring

14 Reproduction Each cell can have one or more nuclei Monokaryotic:
One nuclei Dikaryotic: Two haploid nuclei that function independently

15 Reproduction Dikaryotic hyphae Heterokaryotic:
Nuclei that are from two genetically distinct individuals Homokaryotic: Nuclei are genetically similar

16 Reproduction Sexually Asexually Spores are produced either way
Spread by wind or on insects Suitable environment give rise to new fungal mycelium


18 Reproduction Sexual reproduction 2 compatible mating types fuse
Usually 2 haploid fuse to form diploid Some fungi remain 1n + 1n and not 2n +/- length of time

19 Reproduction Plasmogamy: Fusion of cytoplasm of mycelia Karyogamy:
Fusion of nuclei Zygotes Meiosis Spore formation

20 Reproduction Asexually Molds Produce haploid spores by mitosis Yeasts

21 Haploid (n) Heterokaryotic stage Heterokaryotic (unfused nuclei from
Fig Key Haploid (n) Heterokaryotic stage Heterokaryotic (unfused nuclei from different parents) PLASMOGAMY (fusion of cytoplasm) Diploid (2n) KARYOGAMY (fusion of nuclei) Spore-producing structures Zygote SEXUAL REPRODUCTION Spores ASEXUAL REPRODUCTION Mycelium Figure 31.5 Generalized life cycle of fungi MEIOSIS GERMINATION GERMINATION Spores

22 Fungi Heterotrophs Secrete hydrolytic enzymes (exoenzymes)
Absorb nutrients(organic molecules)

23 Nutrients Digest wood (cellulose) Absorb the glucose
Lignin (found in wood) Decomposer of living or dead organisms Yield carbon, nitrogen and phosphorus

24 Nutrients Obtain nutrients from tiny roundworms called nematodes
Paralyze Penetrate Absorb nutrients from body Nitrogen source

25 Metabolic pathways Anaerobic fermentation Wines & cheeses Soy sauce
Antibiotics & steroids Yeasts (single cell fungi) Bioremediation Using organisms to break up a toxin

26 Symbiosis Lichens Fungus & photosynthetic partner (algae)
Mutualism some are parasitic Hyphae penetrate cell walls of algae Obtain nutrients from the algae Protects the algae from too much sun

27 Symbiosis Lichens first to invade a harsh environment
Colored - pigments -protect the algae from the sun Pigments are used as natural dyes

28 Lichen

29 A foliose (leaflike) lichen
A fruticose (shrublike) lichen Figure Variation in lichen growth forms Crustose (encrusting) lichens

30 Mycorrhizae Tree (plant) roots with fungi
Fungi function as an extension of roots Plants absorb more nutrients, such as Zn, P, Cu Fungi gets organic materials from the plant

31 Mycorrhizae 1. Arbuscular: Fungal hyphae penetrate the trees roots
Form coils around roots More common 2. Ectomycorrhizae: Hyphae do not penetrate the roots Helps trees grow in infertile areas


33 Endophytes Fungus lives inside the plant Intercellular spaces
Help defend plant against herbivores Symbiotic relationship between fungi & ruminant animals Fungi helps digest the cellulose

34 Parasitic Mycosis Fungal infection Ringworm Athlete’s foot
Candida albicans

35 Parasitic Aspergillus Produces toxin harmful to humans. Pneumocystis
Causes a rare pneumonia in AIDS patients Chytridomycosis Fungal infection that harms amphibians Other fungal infections harm plants Chestnut trees, corn


37 Distinguishing Features
Figure 31.UN07 Fungal Phylum Distinguishing Features Chytridiomycota (chytrids) Flagellated spores Zygomycota (zygomycetes) Resistant zygosporangium as sexual stage Glomeromycota (arbuscular mycorrhizal fungi) Arbuscular mycorrhizae formed with plants Ascomycota (ascomycetes) Sexual spores (ascospores) borne internally in sacs called asci; vast numbers of asexual spores (conidia) produced Figure 31.UN07 Summary of key concepts: fungi lineages Basidiomycota (basidiomycetes) Elaborate fruiting body (basidiocarp) containing many basidia that produce sexual spores (basidiospores)

38 Fungi Mycologists: scientists that study fungus Five groups
1. Chytrids 2. Zygomycetes 3. Glomeromycetes 4. Ascomycetes 5. Basidiomycetes

39 1. Chytridiomycota (chytrids)
Aquatic fungi Flagellated spores called zoospores Diverged earliest Chitin in the cell walls

40 2. Zygomycota Bread molds Fruit molds Zygosporangium:
Contains one or more diploid nuclei Forms a hard covering Good growth conditions Undergoes meiosis then mitosis Releases spores


42 Zygomycota Key Haploid (n) Heterokaryotic (n + n) Diploid (2n) Mating
PLASMOGAMY Mating type (+) Gametangia with haploid nuclei Mating type (–) 100 µm Young zygosporangium (heterokaryotic) Rhizopus growing on bread SEXUAL REPRODUCTION Dispersal and germination Zygosporangium Sporangia KARYOGAMY Spores Diploid nuclei Sporangium ASEXUAL REPRODUCTION MEIOSIS Dispersal and germination 50 µm Mycelium


44 Fig. 31-6 2.5 µm Figure 31.6 Penicillium, a mold commonly encountered as a decomposer of food

45 3. Glomeromycetes Arbuscular mycorrhizae Hyphae with plant roots
Very few species

46 4. Ascomycetes Sac fungi Marine, freshwater & terrestrial Yeast
Asci: sac like structure containing sexual spores Ascocarps: contain asci Fruiting bodies Microscopic or macroscopic

47 Key Ascomycota Conidia; mating type (–) Haploid spores (conidia)
Haploid (n) Dikaryotic (n + n) Diploid (2n) Dispersal Germination Mating type (+) ASEXUAL REPRODUCTION Hypha PLASMOGAMY Ascus (dikaryotic) Conidiophore Mycelia Dikaryotic hyphae Mycelium Germination SEXUAL REPRODUCTION KARYOGAMY Dispersal Diploid nucleus (zygote) Asci Eight ascospores Ascocarp Four haploid nuclei MEIOSIS


49 Morchella esculenta Tuber melanosporum Figure 31.15
Figure Ascomycetes (sac fungi) Morchella esculenta Tuber melanosporum

50 5. Blasidiomycetes Mushrooms, shelf fungi, puff balls
Blasidium (Latin means “little pedestal”) Long-lived dikaryotic mycelium Leads to more genetic re-combinations Blasidiocarps (mushroom) Produced sexually Fruiting bodies Wood decomposers

51 Blasidiomycetes Dikaryotic mycelium Haploid mycelia Mating type (–)
PLASMOGAMY Mating type (–) Mating type (+) Gills lined with basidia Haploid mycelia SEXUAL REPRODUCTION Basidiocarp (n+n) Dispersal and germination Basidiospores (n) Basidium with four basidiospores Basidia (n+n) Basidium Basidium containing four haploid nuclei KARYOGAMY MEIOSIS Key Haploid (n) Dikaryotic (n +n) Diploid nuclei 1 µm Basidiospore Diploid (2n)

52 Maiden veil fungus Figure 31.17c
Figure 31.17c Basidiomycetes (club fungi) (part 3: maiden veil fungus) Maiden veil fungus

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