BIOL 110 Chapter Notes - Chapter 31: Monophyly, Ascus, Chitin

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22 Jan 2017

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Concept 31. 1: fungi are heterotrophs that feed by absorption. Nutrition and ecology: heterotrophs, but they absorb nutrients from the environment outside of its body, secrete powerful hydrolytic enzymes, can digest compounds from living and dead sources, fungi are decomposers, parasites, and mutualists. Body structure: multicellular filaments and single cells (yeasts, mostly grow as filaments, some both, few just yeasts. Tubular cell walls surrounding the plasma membrane and cytoplasm of cells. It infiltrates the material on which the fungus feeds. Maximizes its sa-v ratio: fungi cell walls are strengthened by chitin. Also found in arthropods: as fungi grow, they move into new territory, cytoplasmic streaming. Specialized hyphae in mycorrhizal fungi: some have specialized hyphae that can actually allow them to feed on living animals, mutually beneficial relationships between such fungi and plant roots are called mycorrhizae. Plant supplies carbs and organic materials, fungus provides water and nutrients.

Related Questions

Fungi Fungi are the great decomposers of the biosphere. Most plants form mycorrhizae with fungi to increase absorptive area without having to grow more roots, in this relationship fungi recieve carbohydrates from plants. Humans consume fungi, mushrooms, may use fungi as a source of drugs for blood pressure, antibiotics and immunosuppresive drugs. Fungi are used in biotechnology to produce fermetation products, and some have been very useful models to study gentics in eukaryotic cells that are unicellular such as yeasts. About one third of fungi may cause infections, mycoses, in plants, animals and humans. Fungi tolerate concentration of salt and sugar that plasmolyze bacteria in perserved foods exposed to air which contains fungal spores may germinate and may spoil food. Fungi have two body shapes, molds and yeasts. Mold are large and made of long filamentous hyphae. Hyphae form mats called mycelium ( plural is mycelia). Mycelia may extend for miles underground, making fungi the largest organism on earth. The visible portion of subterrean fungi are the fruitng bodies such as mushrooms. Yeasts are globular and unicellular. They may bud forming up 24 daughter cells from a single cell. When budding is incomplete it may produce a psuedohypa. Fungi that may exist in both body types are dimorphic fungi. In general, the yeast form of a dimorphic fungus is a pathogen, the filamentous form is not pathogenic. Examples are Histoplasmosis capsulatum (histoplasmosis) and Coccidiodes immitis (coccidioidomycosis). Fungi are saprobes, they absorb nutrients from the remains of dead plants or they lasso nematodes. Fungi may derive nutrients from a living plant utilizing haustoria which are modified hyphae that penetrate living plant tissue. Some fungi use melanin to absorb gamma rays which they convert to chemical energy. Some herbivores have fungi in thier gut microbiome to help digest plants. Zygomycota contains 1100 species and reproduces asexually through sporangiaspores, which form in a sac called a sporangium on a stalk called a sporangiaphore. An example is Nosema which is an obligate intracellular parasite in insects and honeybees. Ascomycota havd 32,000 species form haploid ascospores in sacs called ascus (asci plura) and reproduce asexually with condiospores which develop on the tips of hyphae on stalks called conidiophores. Examples are Claviceps purpurea, ergot, which grows on grain and causes abortions in cattle and hallucinations in humans. Penicillium the source of the first antibiotic discovered by Fleming in the 1940s. Saccharomyces, a facultative anaerobe, ferments sugar to produce alcohol and carbon dioxide gas and is used in baking and brewing. Neurospora was used as a model to study molecular biology, Beadle and Tatum established one gene one enzyme using this model organism.

14. Why are there more antibacterial drugs than antifungal drugs? Basidiomycota have fruiting bodies called basidiocarps. Basidiospores are dispersed by the wind and germinate in warm moist environments. An example is the pathogen Cryptococcus neoformans the leading cause of fungal meningitis

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1.A mycologist visits your biology class and discusses herresearch on a particular fungus that lives on the bark of damagedspruce trees. She explains that the fungal hyphae of her researchorganism is heterokaryotic. You raise your hand and request thatshe define that word. Her correct response is

heterokaryotic means that thenuclei of the fungal hyphae are genetically the same.

heterokaryotic means that eachcompartment of the hyphae contain two distinct nuclei.

heterokaryotic means that thenuclei of each compartment of the hyphae are geneticallydistinct.

heterokaryotic means that each compartment of the hyphaecontains only one nucleus.

2. Select the true statements concerning reproduction ofbasidiomycetes. (Check all that apply.)

The adult forms of a typicalbasidiomycete consists of a mass of dikaryotic primarymycelia.

The secondary mycelia fuse to formprimary mycelia. The primary mycelia form the fruiting body.

The gills of an Amanitamushroom contains basidiospores.

Karyogamy produces a diploid zygotethat undergoes meiosis.

Meiosis produces basidiospores, and the fusion of spores fromdifferent mating strains produces the primary mycelium.

3. In the life cycle of a zygomycete, after the zygospore isformed, the next event will be

dikaryon formation.