deck_1244966 Flashcards
Kingdom Fungi
- Heterotrophic 1. Decomposers (saprobes) 2. Parasites/pathogens (of plants and animals) 3. Mutualists 4. Predaceous (few species)- Chitin (carbohydrate) based cell wall- Mostly multicellular + Yeast is the only exception.- Possess hyphae + Septate or coenocytic- Thallus/micellium + Body of hyphae- May possess haustoria + Specialized hyphae designed for predaceon.
Fungal disease examples
- Black stem rust- Ergots (lysergic acid, or LSD) on rye- Pink ear rot on corn
Examples of mutualistic fungi
- Lichens- Mycorrhizae
Predaceous fungi have adapted ___ for catching prey.
Haustoria
Haustorium
Specialized hypha that inserts itself inside of a host cell (plant/animal) to absorb it from within.
Septate hyphae
Contain septa (singular “septum”) that form cross-walls, separating the individual cells within the the hypha. Septa contain pores that allow organelles to move between compartments.
Coenocytic hyphae
Non-septate hyphae. Nuclei float around freely with the hypha. These hyphae are one large cell.
Mycelium/thallus
A mass of individual hyphae composing the body of the fungus. - Used in feeding. - If fruiting body is not visible, mycelia may still stretch for vast distances underground.
Asexual reproduction in fungi
- Mycelium (n) forms spore-producing structures called sporangia.2. Sporangia releases spores into the environment.3. Spores attach to a food source and germinate, developing their own mycelium.- Asexual reproduction occurs when food is scarce.- Spores may lay dormant and not germinate until food is available.
Sexual reproduction in fungi
- Mycelium (n) of two compatible (+/-) attract one another through the release of pheromones and form side branches to connect.- The hyphae touch and their cytoplasms fuse, engaging in plasmogany.- This area where both hyphae meet becomes its own heterokaryotic cell (n+n).- Karyogamy occurs when the nuclei pair up and fuse together, causing the cell to become a zygote (2n). This is when fertilization is occurring.- Zygote undergoes meiosis to form (n) cells that will develop into sporangia.
Plasmogany
Fusion of cytoplasm - From (n) to (n+n)
Karyogamy
Fusion of nuclei - From (n+n) to (2n) - Also referred to as “fertilization.”
Heterokaryotic hyphae
Possess 2 or more genetically different nuclei resulting from the fusion of hyphae. + Dikaryotic hyphae are a subtype of heterokaryotic hyphae.
Dikaryotic hyphae
Posses exactly 2 nuclei in each cell.
Today’s fungi evolved from ocean dwelling ___ which possessed ___.
Chytrids, flagella
Fungi Phylums
- Chytridiomycota- Zygomycota- Ascomycota- Basidiomycota- Deuteromycota
Phylum Chytridiomycota
“Chytrids” - Aquatic, water mold fungus - Flagellated spores, unique to this phylum - Most primitive fungi - Saprobes or parasitic
Phylum Zygomycota
- Mostly terrestrial + Soil or decaying material- Spores dispersed by air- Mostly coenocytic hyphae- Possess zygosporangium- E.g., Rhizopous (black bread mold) + Zygosporangium is the black portion + Mycelia is the white portion
Zygosporangium
Fruiting body of zygomycota + (n+n)
Zygomycota life cycle
Same as general fungus life cycle, but the zygote in sexual reproduction is referred to as a “zygosporangium” (n+n) following plasmogamy, and becomes a zygote, called a “zygospore” (2n), following karyogamy.- Can determine if fungus was produced asexually or sexually based on if it came from mycelium or a zygosporangium.
Gametangia
Haploid cells from genetically different mycelia after meeting one another but prior to plasmogany.
Phylum Ascomycota
“Sac fungi”- Most diverse group + Marine, freshwater, and terrestrial- Saprobes or parasites- Symbiotic- Include unicellular fungi (yeasts) to very large fungi- Spores dispersed by air- Septate hyphae- E.g., Aspergillus (in peanuts, toxic), Saccharomyces (yeast), Penicillum, ergots (lysergic acid, or LSD) on rye, morels and truffles + Used to make cheese, bread, and wine.
Ascomycota life cycle (asexual)
- Conidiophore releases conidia (spores)- Conidia germinate and develop into mycelia, which then become conidiophores. + Conidiophore with conidia looks like dreadlocks! Only referred to as conidia(phores) in asexual reproduction.
Ascomycota life cycle (sexual)
- One organism’s hyphae will form an “ascogonium” and a genetically different organism will form an “antheridium.”- These structures meet and undergo plasmogamy when the antheridium (now n) deposits its nuclei into the ascogonium (now n+n).- The now (n+n) and (n) hyphae form the “ascocarp,” or fruiting body.- (n+n) Asci (singular “ascus”) will form on the tips of the hyphae of the ascocarp.- Only the ascus undergoes karyogamy to become 2n, while the rest of the hyphae remains (n+n).- Ascus undergoes meiosis to form 4 (n) “ascospores”, which undergo mitosis for a total of 8 ascospores within the ascus.- The ascus releases the ascospores into the atmosphere.- Germination occurs and mycelium develop.Only cells facing the inside of the ascocarp develop an ascus.
Phylum Basidiomycota
“Club fungi”- Major decomposers of wood (lignin)- Septate hyphae- Terrestrial- World’s largest organism- Only reproduce sexually- May smell bad to attract flies that distribute their spores- E.g., mushrooms, toadstools, shelf fungi, puffballs and rusts
Basidiomycota life cycle
- Compatible (n) mycelia meet and undergo plasmogamy.- (n+n) mycelium forms between them, and develops into a “basidiocarp” (fruiting body). The entire fruiting body is (n+n).- Basidiocarp develops “basidia,” similar to the ascus, which is (n+n) until it undergoes karyogamy.- After karyogamy, which only occurs in the (2n) basidium, they undergo meiosis to create 4 basidiospores.- Basidiospores attach externally to the basidium until they are ready to be released (forms a club shape).- After release, spores are able to germinate.
Phylum Deuteromycota
“Imperfect fungi”- No known sexual reproduction (“imperfect” for this reason)- Reproduce asexually through conidiospores- E.g., certain molds, ringworm, predatory fungus (nematode-eater!)
Lichen
Organism produced by a symbiotic relationship between algae/cyanobacteria and fungus (asco/basidio). - Fungus receives sugars from photosynthesis. - Algae receives moisture from hyphae.
Mycorrhizae
Mutualistic relationship between roots and fungi (zygo/asco/basidio). Tends to increase plant growth.- Ectomycorrhizae or endomycorrhizae - Fungus obtains sugars from photosynthesis. - Roots receive water and minerals from hyphae.
Ectomycorrhizae
Fungus wraps around the outside of the root.
Endomycorrhizae
Hyphae penetrate the cell walls of the root.
Commercial use of fungi
Food: Mushrooms, truffles morels, etc.Yeasts: Fermentation of wine, beer, and raising of bread.Antibiotic production: Penicillin from penicillum
Fungi and health
Most fungi are opportunistic and can cause health problems.- Grows in human tissues, especially the lungs + Histoplasmosis- Causes allergies + Aspergillus- Produces mycotoxins - Aspergillus is peanuts and cereals
Histoplasmosis
Condition of having fungus in the lungs, most common in spelunkers due to exposure to bat feces.
Exoenzymes
Used by fungus to break down food into smaller molecules that can then be absorbed.
Predecessor of plants
Phylum Chlorophyta, Class Charophycea”Green algae” + E.g., spirogya- Unicellular, colonial or multicellular- Chlorophyll A & B- Chloroplasts- Cell wall: cellulose and pectin- E.g., Chlamydomonas (unicellular), Volvox (colonial), and Ulva (multicellular)
Shared characteristics between charophycea and land plants
- Intracellular structures + Rosette cellulose-synthesizing protein complex + Peroxisome enzymes + Sporopollenin- Structure of flagellated sperm
Kingdom Plantae
- Multicellular- Photosynthetic autotrophs + Chlorophylls A & B- Monophyletic + One common ancestor for all species- Cell wall: cellulose-based- Reproduce by alternation of generations + Gametophyte and sporophyte- Apical meristems + Allow for tips of roots and shoots grow by acting as stem cells- Starch storage- Gamete evolution + Mostly oogamy but can also use isogamy and anisogamy
Evolution of land plants
- Land colonization began 400 million years ago.- Likely ancestors were green algae.- New issues for land plants and their adaptations: a. Obtaining water - Root system b. Transporting water and nutrients - Conduction tissue c. Water loss due to increased temperatures - Cuticle: wax surface d. Gas exchange - Stomata e. Gravity - Support tissue + E.g., wood f. Reproduction in dry, terrestrial environments and alternation of generations - Gametes protected within gametangia
Bryophytes
“Non-vascular plants”- Lack vascular tissue- Unisexual gametophyte is dominant and sporophyte is ephemeral (short-lived) and dependent on gametophyte.- Most have cuticle and stomata on their leaf-like structures + Hepatophyta does not!- Flagellated sperm cells + Dependent on water for fertilization- Posses rhizoids but no true roots- Small due to lack of vascular tissue- Usually in moist environments- Classification of bryophytes + Phylum Bryophyta + Phylum Hepatophyta + Phylum Anthocerophyta
Phylum Bryophyta
“Mosses”- Most advanced bryophytes- Possess conducting cells- Possess rhizoids- Possess protonemata + Chain-like thread of cells that develops into the gametophyte- Possess cuticle and stomata- E.g, Sphagnum moss
Rhizoids/rhizome
Used to anchor primitive plants into place. Not used for water absorption.
Cuticle
Coating of waxy lipids that retards water loss.
Stomata
Small closable openings in leaves and stems that are used to regulate oxygen exchange.
Gametangia
Multicellular organs that enclose plant gametes and prevent them from drying out.
Bryophyta life cycle
- Spores are either male or female. They germinate and form “protonemata.”- The protonemata forms a bud that develops into a “gametophore.”- At the tip, the male gametophore will develop “antheridia” that produce sperm, and the female will develop “anrchegonia” which hold a single egg within each of them. This entire structure is called either the male or female “gametophyte.”- Rain causes sperm to splash out of the antheridium and into the archegonium.- Fertilization occurs within the archegonium.- Zygote (2n) develops into an embryo. It stays inside of the archegonium until emerging as a young sporophyte.- After emerging, the sporophyte develops a capsule (sporangium). The sporangium contains “peristome” which control spore release.- Sporangium releases spores into the environment.
Phylum Hepatophyta
“Liverworts”- Simplest bryophytes- Lack conducting cells + Water is passed individually from one cell to another.- Lack cuticle and stomata
Hepatophyta life cycle
Similar to other byophytes, but the achegonium is on the underside of the female gametophyte. Sperm within the antheridium are located on top of the male gametophyte, and must swim up and into the archegonium for fertilization to occur.
Phylum Anthocerophyta
“Hornworts”- Closely related to green algae- Found along waterfalls and riversides, associated with freshwater.- Possess stomata
Alternation of generations
Life cycle of all land plants. Alternation between gametophyte and sporophyte stage. - Gametophytes are (n) and sporophytes are (2n)
Vascular seedless plants
- Dominant plants during Carboniferous period (300-350 million years ago)- Possess conductive tissue- Sporophyte-dominant life cycle + Gametophyte is ephemorous- Large sporophytes and small gametophytes that are independent of one another since they can both photosynthesize.- Posses xylem and phloem- Evolution of roots- Evolution of leaves + Microphylls + Megaphylls- Branching + Allows for more sporangia to be produced- Sporangia arranged in “strobilli”
Xylem
Transports water and nutrients from the soil.
Phloem
Transports food in the form of sugar.
Microphyll
Small leaf. An extension of the stem surrounding by very little tissue with no branching.