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54 Cards in this Set
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Mycology |
the study of fungi |
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Fungi (gram positive) |
- have cell walls of chitin, glucans, mannans - but NO peptidoglycan - all are chemoheterotrophic: parasitic or saprophytic - single or multicellular - microscopic to the "world's largest organism" - nonmotile - Aerobic or facultatively anaerobic |
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List the defining characteristics of Fungi |
Vegetative structures - fungal colonies, composed of cells involved in catabolism and growth - a large diverse group - important as 1. pathogens, 2. decay organisms, 3. food and in industrial processes such as brewing, and wine and cheese making |
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Molds (and Fleshy Fungi) |
consists of a thallus (body) and hyphae (long filaments of cells joined together) - usually have a filamentous (threadlike) structure |
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Hyphae (Septate vs. Coenocytic) |
Septate Hypha: hyphae separated by septa or walls Coenocytic Hypha: hypha with no septa and appear as long, continuous cells with many nuclei |
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Mycosis |
any disease caused by a fungus (usually Chronic) - divided into 5 modes of entry 1. Systemic 2. Subcutaneous 3. Cutaneous 4. Superficial 5. Opportunistic |
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Mycelium |
a filamentous mass of hyphae of a mold visible to the unaided eye |
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Yeasts |
non filamentous, unicellular fungi that are typically spherical or oval. They are found as white powdery coating on fruits and leaves. (Widely distributed in nature) - capable of facultative anaerobic growth which allows them to survive in various environments Aerobic - metabolize carbohydrates to CO2 and H2O Anaerobic - ferment carbohydrates to ethanol and carbon dioxide --> used to brew beverages/leaven dough |
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Budding Yeasts (main yeasts) |
- divide unevenly, parent cell forms a protuberance or bud which elongates and receives a nucleus from the parent cell which allows it to break away Pseudohypha - a bud that fails to break off of Budding Yeasts |
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Fission Yeasts (do not focus on this one) |
- divide evenly to produce two new cells. Parent elevates, two nuclei produced/divides, two offspring cells produced. Growth on solid medium similar to bacterial medium. |
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Important Yeasts |
Saccharomyces spp. = baking and brewing yeasts - produce ethanol in brewed beverages - produce carbon dioxide to raise bread dough |
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Candida albicans |
- opportunistic pathogen (candidiasis, thrush, yeast infection) - in normal microbiota - problem in infants, HIV infected, diabetics, or after antibiotic use |
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Dimorphism (a characteristic of some yeasts) |
- some yeasts are dimorphic (have 2 forms: yeast cells and hyphae) - yeast form in animal host, reproduce by budding - hyphal form in soil, reproduce by vegetative/aerial hyphae |
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Cryptococcus neoformans |
a yeast-like pathogen that causes cryptococcosis - has a capsule (rare in eucaryotes) |
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Bacterial Endospore |
- allow for survival in adverse environmental conditions - single vegetative cell produces one endospore, eventually germinates to produce a single vegetative cell. - not reproductive |
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Fungal Spores |
- after a mold forms a spore, the spore detaches from the parent and germinates into a new mold - reproductive because another organisms grows from the spore - are not as a tolerant to adverse environment compared to bacterial spores |
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Asexual Spores |
- formed by the hyphae of one organism - offspring are genetically identical - produced by individual fungus through mitosis and subsequent cell division, no fusion of nuclei of cells |
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Asexual Spores |
Conidiospore (Condium) - uni/multicellular spore not enclosed in a sac Arthroconidia - formed by fragmentation of septate hypha into single, slightly thickened cells Blastoconidia - buds coming off parent cell Sporangium Spore - formed within a sporangium sac, formed at end of aerial hypha (Sporangiophore: contains many sporangiospores) |
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Sexual Spores |
- result from the fusion of nuclei from two opposite matching strains of the same species of fungus - produced less frequent compared to asexual spore - will have genetic characteristics of both parental strains |
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Sexual Spores (3 phases) |
1. Plamogamy - Haploid nucleus of donor cell (+) penetrates cytoplasm of recipient cell (-) 2. Karyogamy - The (+) and (-) nuclei fuse to form a diploid zygote nucleus. 3. Meiosis - the diploid nucleus gives rise to haploid nuclei (sexual spores), some of which may be genetic recombinants |
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Nutritional Adaptations |
1. Fungi usually grow better in pH of about 5, which is too acidic for bacteria 2. Molds (aerobic) Yeasts (facultative anaerobic) 3. Resistance to osmotic pressure (high sugar or salt concentrations) 4. Grow on low moisture 5. Require less nitrogen 6. capable of metabolizing complex carbs |
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Benefits of Fungi |
1. used as biological control of pests 2. Tricholemma used to produce cellulase which helps create clear fruit juice 3. Taxomyces produces anti-cancer drug (Taxol) 4. used to make wine,bread |
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Harmful Effects of Fungi |
1. can devastate forests by blocking a tree's circulation or by killing the shoots of trees 2. spoilage of fruits, grains and vegetables |
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Lichen |
- combination of green alga (acynobacterium) and a fungus - very diff from the alga or fungus growing alone, lichen does not exist if partners are separated -can inhabit areas neither fungi or algae can survive alone, first to colonize newly exposed soil/rock - secrete organic acids that chemically weather rock/accumulate nutrients needed for plant growth - grouped into 3 morphologic categories: 1. Crustose Lichen: grow flush 2. Foliose Lichens: Leaflike 3. Fruticose Lichen: Fingerlike |
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Role of Alga (in Lichen) |
- provides valuable nutrients |
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Role of Fungus (in Lichen) |
- serves as points of attachment for alga - protects alga from desication (state of extreme dryness) |
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Other Fungi |
- mushrooms, etc: hyphae are compressed together to form structure - mushroom is spore-forming structure; main mycelium is in the soil |
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Algae (Eukaryotic, have cell walls) |
- not a taxonomic group, way to describe photoautotrops that lack roots/stems of plants - lack embryos of the true plants - No specialized tissues - most are in the ocean, depending on nutrients, surfaces, and wavelengths of light |
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Algae Vegetative Structures |
Thallus: body of multicellular alga Thalli of larger multicellular algae (seaweeds) consists of: 1. Branched hold fasts (anchors alga to rock) 2. Stem-like Stipes 3. Leaflike Blades |
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Algae Life Cycle |
- all algae can reproduce asexually 1. Multicellular algae with thalli and/or filament --> fragment to form new thallus or filament 2. Unicellular algae: nucleus divides and move to opposite parts of cell -> divides into two complete cells (cytokinesis) |
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Algae Nutrition |
- photosynthetic or photoautotrophs |
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Different Types of Algae |
- Algae are classified according to RNA sequences, structures, pigments and other qualities 1. Dinoflagellates (plankton) 2. Brown Algae (Kelp) 3. Water molds (Oomycota) 4. Diatoms (phytoplankton/look like glass) 5. Green Algae |
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Roles of Algae in Nature |
1. Produce 80% of Earth's oxygen 2. Source of petroleum when heat/pressure from Earth turns them into fossils LUL 3. many Unicellular algae are symbionts in animals Ex. Alga in clam provide it with glycerol 4. Basis of aquatic food chains/webs 5. Source of chemicals - (agar) 6. Algal biofuels 7. Algal blooms in polluted water |
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Protozoa |
Unicellular, Eukaryotic, microscopic (largest barely visible without magnification) - no cell walls - heterotrophic: parasitic or "freeliving" (nonparasitic) - usually motile |
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Protozoa Four Categories |
1. Amoebas (move by pseudopodia/cytoplasmic streaming) 2. Flagellates 3. Apicomplexa 4. Ciliates |
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Amoebas |
- move my pseudopodia Phagocytosis: engulfing of solid particles by cells - phago = eating - cyto = cell - how protozoa eat and how our white blood cells destroy many pathogens |
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Amoebas |
- Amebiasis or amoebic dysentery |
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Trophozoite |
- feeds upon bacteria and small particulate nutrients - active, feeding form of protozoa |
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Cyst |
- dormant, survival form - a protective capsule some protozoa may produce - permits organisms to survive under adverse conditions - enables parasitic species to survive outside in host |
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Oocytes |
- reproductive structure in which new cells are produced asexually in Apricomplexia phylum |
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Phagocytosis |
1. Phagocyte sucks up food or pathogen 2. Stores it in vacuole 3. Lysosome (a bag of digestive enzymes) fuses with vacuole |
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Helminths |
1. Platyhelminths (flatworms) 2. Nematoda (roundworms) - multicellular eukaryotic animals that generally possess circulatory, nervous, excretory, and reproductive system.
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Helminths Characteristics |
1. Lack a digestive system 2. Nervous system reduced 3. Locomotion lacking or reduced 4. Complex reproductive system |
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Larval Stage |
- developmental stage of the parasite |
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Intermediate Host |
- where the larva lives - contains sexually immature form of a helminth |
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Definitive Host |
- contains sexually active/mature form of a helminth |
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Dioecious |
- male reproductive organs in one individual - female reproductive organs in another individual - female and male in the species look different |
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Monoecious/Hermaphroditic |
- one animal has both male and female reproductive organs - two hermaphrodites may copulate and simultaneously fertilize each other |
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Platyhelminth or Flatworm |
- dorsoventrally flattened - parasitic flatworms 1. Trematodes: Flukes 2. Cestodes: Tapeworms |
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Flatworm: Trematodes (Flukes) |
- flat, leaf shaped bodies with a ventral sucker and an oral sucker, holds the organism in place - given common names according to tissue the definitive host lives |
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Cuticle |
- outer covering of a fluke or cestode that allows for food absorption
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Flatworm: Cestodes (Tapeworm) |
- intestinal parasites - Hermaphroditic = having both ovaries and testes (being both sexes at the same time) |
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Cestodes (Tapeworm) |
Scolex - head of cestodes with suckers for attaching to intestinal mucosa of the definitive host Proglottids - segments, continually produced by neck region of the scolex, as long as scolex is attached/alive Cysticeri - cysts by tapeworms in meat -> cysticeri is ingested and scolex anchors in small intestine to produce proglottids |
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Nematodes (Roundworms) |
- cylindrical and tapered at each each - have a complete digestive system with mouth, intestine, and anus - intestinal roundworms are the most common causes of chronic infectious diseases |
