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Fungi

Fungi. Mycology- study of fungus. Fungi. Characteristics. Fungi are NOT plants (they are eukaryotes) Non-photosynthetic ( chemoheterotrophs - require organic compounds for energy). The Characteristics of Fungi. Most are aerobic Non-motile Most are saprobes (live on dead organisms)

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Fungi

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  1. Fungi

  2. Mycology- study of fungus Fungi

  3. Characteristics

  4. Fungi are NOT plants (they are eukaryotes) Non-photosynthetic (chemoheterotrophs- require organic compounds for energy) The Characteristics of Fungi

  5. Most are aerobic Non-motile Most are saprobes (live on dead organisms) Release digestive enzymes to break down organic material or their host The Characteristics of Fungi BREAD MOLD

  6. Important decomposers & recyclers of nutrients in the environment Most are multicellular, except unicellular yeast Lack true roots, stems or leaves The Characteristics of Fungi MULTICELLULAR MUSHROOM UNICELLULAR YEAST

  7. Some fungi are internal or external parasites A few fungi act like predators & capture prey like roundworms The Characteristics of Fungi Predaceous Fungi feeding on a Nematode(roundworm)

  8. Some are edible, while others are poisonous The Characteristics of Fungi EDIBLE POISONOUS

  9. Produce both sexual and asexual spores Classified by their sexual reproductive structures The Characteristics of Fungi Spores come in various shapes

  10. Fungi include puffballs, yeasts, mushrooms, toadstools, rusts, smuts, ringworm, and molds The antibiotic penicillin is made by the Penicilliummold The Characteristics of Fungi Penicillium mold Puffball

  11. Vegetative Structures NON-REPRODUCTIVE

  12. Cell walls are made of chitin (complex polysaccharide) Body is called the Thallus Grow as microscopictubes or filaments called hyphae Structures of Fungi

  13. Tubularshape ONE continuous cell Filled with cytoplasm & nuclei Multinucleate Hard cell wall of chitin also in insect exoskeletons Hyphae

  14. Stolons – horizontal hyphae that connect groups of hyphae to each other Rhizoids – rootlike parts of hyphae that anchor the fungus Hyphae STOLON RHIZOIDS

  15. Cross-walls called SEPTA may form compartments Septa have pores for movement of cytoplasm Form network called mycelia that run through the thallus (body) Hyphae

  16. Absorptive Heterotroph • Fungi get carbon from organic sources • Tips of Hyphae release enzymes • Enzymatic breakdown of substrate • Products diffuse back into hyphae Nucleus “directs” the digestive process Enzymatic breakdown Enzymes Digested material is then used by the hypha

  17. Fungi may be classified based on cell division (with or without cytokinesis) • Aseptate or coenocytic (without septa) • Septate(with septa) Modifications of hyphae NO CROSS WALLS CROSS WALLS

  18. Modifications of hyphae HAUSTORIA – parasitic hyphae on plants & animals Septate Hyphae Coenocytic Hyphae

  19. Hyphae grow from their tips Mycelium is an extensive, feeding web of hyphae Mycelia are the ecologically active bodies of fungi Hyphal growth This wall is rigid Only the tip wall is plastic and stretches

  20. REPRODUCTIVE STRUCTURES ASEXUAL & SEXUAL SPORES

  21. Most fungi reproduce Asexually and Sexually by spores ASEXUAL reproduction is most common method & produces genetically identical organisms Fungi reproduce SEXUALLY when conditions are poor & nutrients scarce REPRODUCTION

  22. Spores are an adaptation to life on land Ensure that the species will disperse to new locations Each spore contains a reproductive cell that forms a new organism Nonmotile Dispersed by wind Spores

  23. Sexual Reproduction

  24. Used when environmental conditions are poor (lack of nutrients, space, moisture…) • No male or female fungi • Some fungi show dimorphism • May grow as MYCELIA or a YEAST –LIKE state (Filament at 25oC & Round at 37oC) SEXUAL REPRODUCTION Dimorphic Fungi

  25. Haploid 1n hyphae from 2 mating types (+ and -) FUSE (Fertilization) Forms ahyphae with 2 nuclei that becomes a ZYGOTE The zygote divides to make a SPORE SEXUAL REPRODUCTION - + SPORE FORMS

  26. ASexual Reproduction

  27. Fragmentation – part of the mycelium becomes separated & begins a life of its own • Budding – a small cell forms & gets pinched off as it grows to full size • Used by yeasts • Asexual spores – production of spores by a single mycelium Three types of Asexual Reproduction

  28. Reproduce by spores • Spores may be Formed: • Directly on hyphae • Inside sporangia • On Fruiting bodies Penicillium hyphae Pilobolussporangia Amanita fruiting body

  29. Fruiting Bodies are modified hyphae that make asexual spores An upright stalk called the Sporangiosphore supports the spore case or Sporangium ASEXUAL REPRODUCTION

  30. Types of Fruiting Bodies: • Basidia • Sporangia • Ascus ASEXUAL REPRODUCTION Sporangia Basidia

  31. Fruiting Bodies Both are composed of hyphae mycelium

  32. Mycelia have a huge surface area More surface area aids digestion & absorption of food Hyphal growth from spore Germinating spore mycelium

  33. Fungi are classified by their REPRODUCTIVE STRUCTURES and SPORES • The reproductive structures are: • BASIDIA - BASIDIOMYCOTA • SPORANGIA - ZYGOSPORANGIA • ASCUS - ASCOMYCOTA It’s All About the Spores!

  34. Spores are made of: • Dehydrated cytoplasm • Protective coat • Haploid cell • Wind, animals, water, & insects spread spores • Spores germinates when they land on a moist surface (new hyphae form) It’s All About the Spores!

  35. Saprobes • Decomposers • Molds, mushrooms, etc. • Parasites • Harm host • Rusts and smuts (attack plants) • Mutualists • Both benefit • Lichens • Mycorrhizas Classification by Nutrition

  36. Major Groups of Fungi • Basidiomycota – Club Fungi • Zygomycota – Bread Molds • Chytridiomycota – Chytrids • AM Fungi - Mycorrhizas • Ascomycota – Sac Fungi • Lichens – Symbiosis (algae & Fungi)

  37. ZYGOmycota

  38. Zygomycota Rhizopus on strawberries • Called the sporangiumfungi • Commonly called molds • Also includes blights • Hyphae have no cross walls (aseptate) • Grow rapidly • Includes bread moldRhizopus stolonifer Tomato Blight

  39. Zygomycota • Asexual reproductive structure called sporangiumatop sporangiospores make spores • Rhizoids anchor the mold & release digestive enzymes & absorb food • Stolonsconnect the fruiting bodies

  40. Zygomycota • Sexual spores are produced by conjugation when (+) hyphae and (-) hyphae fuse • Sexual spores are called ZYGOSPORES • Zygospores can endure harsh environments until conditions improve zygospore

  41. Basidiomycota

  42. Basidiomycota • CalledClub fungi • Includes: • Mushrooms • Toadstools • Bracket & Shelf fungi • Puffballs • Stinkhorns • Rusts and smuts

  43. Some are used as food (mushrooms) Others damage crops (rusts & smuts) USES For Basidiomycota Portobello Mushrooms Soybean Rust Corn Smut

  44. Seldom reproduce asexually The visible mushroom is a fruiting body Basidiocarp(fruiting body) is made of a stalk called the stipeand a flattened cap with gills called Basidia underneath Basidiospores are found on basidia Annulus is a skirt-like ring around some stipes Vegetative structures found below ground Characteristics of Club Fungi

  45. Hyphal fusion of haploid mycelia mycelium and fruiting body are dikaryotic Mushroom Life Cycle haploid mycelium N 2N N+N Meiosis Nuclear fusion in basidium Fig 31.12 young basidia - the only diploid cells

  46. Ascomycota

  47. Characteristics • CalledSac fungi • IncludesCup fungi, morels, truffles, yeasts, and mildew • May be plant parasites (Dutch elm disease and Chestnut blight) • Reproduce sexually & asexually • Ascus - sac that makes ascospores in sexual reproduction • Specialized hyphae known as Ascocarps contain the asci

  48. Characteristics • Yeasts reproduce asexually by budding (buds break off to make more yeast cells) • Asexual spores called conidia form on the tips of special hyphae called conidiophores CONIDIA

  49. Conidia Formation

  50. Yeasts Budding Saccharomyces

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