BSC 116 Chapter 31: Chapter 31 Textbook Notes

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plumtermite154

15 Feb 2017

School

University of Alabama

Department

Biological Sciences

Course

BSC 116

Professor

Phillip Harris

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Document Summary

Section 31. 1: fungi are heterotrophs that feed by absorption. Like animals, fungi are heterotrophs: cannot make their own food as plants and algae can, unlike animals, fungi do not ingest their food. A fungus absorbs nutrients from the environment outside of its body. Many do this by secreting hydrolytic enzymes into their surroundings. These enzymes break down complex molecules to smaller organic compounds that the fungi can absorb into their bodies and use. Other fungi use enzymes to penetrate the walls of cells, enabling the fungi to absorb to absorb nutrients from the cells. Collectively, the different enzymes found in various fungal species can digest compounds from a wide range of sources, living or dead. Some parasitic fungi are pathogenic, including many species that cause disease in plants: mutualistic fungi also absorb nutrients from a host organism, but they reciprocate with actions that benefit the host.

Related Questions

Which of the following is NOT one of the uses of fungi?

Select one:

a. As a source of antibiotics.

b. To make drinks, like beer.

c. To produce fabrics like cotton and linen.

d. To make food, like bread.

e. As a direct food source: mushrooms, for example.

How do fungi get nutrients?

Select one:

a. They ingest organic material, break it down internally, and absorb the released nutrients through their digestive system.

b. Fungi use each of these methods to get nutrients.

c. They secrete enzymes that break down dead matter or living organisms and absorb the released nutrients.

d. They receive nutrients from other organisms that trade the nutrients for protection from pathogens.

e. They produce their own by photosynthesis.

Why is fungi's role as biodegraders so important to ecosystems?

Select one:

a. It transfers the energy from sunlight into sugars.

b. It provides nutrients and oxygen to the ecosystem.

c. It protects plants from harmful viruses and bacteria.

d. It keeps the level of prey animals down so they do not overwhelm the ecosystem.

e. It recycles and reuses organic molecules so they are not wasted.

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