General Characteristics of Fungi: chitin more related to animals

Transcription

1 Fungus, plural fungi, any of about 99,000 known species of organisms of the kingdom, which includes the yeasts, rusts, smuts, mildews, molds, and mushrooms. are among the most widely distributed organisms on Earth and are of great environmental and medical importance. Many fungi are free-living in soil or water; others form parasitic or symbiotic relationships with plants or animals. are eukaryotic organisms; i.e., their cells contain membrane-bound organelles and clearly defined nuclei. Historically, fungi were included in the plant kingdom; however, because fungi lack chlorophyll and are distinguished by unique structural and physiological features (i.e., components of the cell wall and cell membrane), they have been separated from plants. In addition, fungi are clearly distinguished from all other living organisms, including animals, by their principal modes of vegetative growth and nutrient intake. grow from the tips of filaments (hyphae) that make up the bodies of the organisms (mycelia), and they digest organic matter externally before absorbing it into their mycelia.

2

3 General Characteristics of : Eukaryotic Decomposers the best recyclers around No chlorophyll non photosynthetic Most multicellular (hyphae) some unicellular (yeast) Non-motile Cell walls made of chitin (kite-in) instead of cellulose like that of a plant Are more related to animals than plant kingdom Lack true roots, leaves and stems Absorptive heterotrophs -Digest food externally and then absorb it Lack of chlorophyll affects the lifestyle of fungi Not dependent on light Can occupy dark habitats Can grow in any direction Can invade the interior of a substrate with absorptive filaments

4 Structures Body of fungus made of tiny filaments or tubes called hyphae. Contain cytoplasm and nuclei (more than 1) Each hyphae is one continuous cell Cell wall made of chitin A tangled mess of hyphae is called mycelium Rhizoids are root-like parts of fungi that anchor them to the substrate (whatever they are bonding to) Mycelium increase the surface area of the fungi to absorb more nutrients.

5 6 Interesting Facts About 1) can cure disease. Many may be familiar with the antibiotic known as penicillin. Did you know that it was produced from a mold that is a fungus? Around 1929, a doctor in London, England wrote a paper on what he called 'penicillin' which he had derived from the Penicillium notatum mold (now known as Penicillium chrysogenum). It had the ability to kill bacteria. His discovery and research started a chain of events that would lead to the development of many antibiotics that would save countless lives. Similarly, the antibiotic cyclosporine is a key immunosuppressant and is used in organ transplants. 2) can also cause disease. Many diseases can also be caused by fungi. For example, while many associate ringworm with being caused by a worm, it is caused by a fungus. It gets its name from the circular shape of the rash produced. Athlete's foot is another example of a disease caused by fungi. Many other diseases such as: eye infections, valley fever, and Histoplasmosis are caused by. 3) are vital to the environment. play a key role in the cycle of nutrients in the environment. They are one of the main decomposers of dead organic matter. Without them, the leaves, dead trees, and other organic matter that build up in the forests wouldn't have their nutrients available for other plants to use. For example, nitrogen is a key component that is released when fungi decompose organic matter. 4) can last for a long time. Depending on the conditions, many fungi, like mushrooms, can be dormant for extended periods of time. Some can sit dormant for years and even decades and still have the ability to grow under the right conditions. 5) can be deadly. Some fungi are toxic. Some are so toxic that they can cause instant death in animals and humans. Deadly fungi often contain a substance known as amatoxins. Amatoxins typically are very good at inhibiting RNA polymerase II. RNA polymerase II is a necessary enzyme involved in the production of a type of RNA called messenger RNA (mrna). Messenger RNA plays an important role in DNA transcription and protein synthesis. Without RNA polymerase II, cell metabolism will stop and cell lysis occurs. 6) can be used to control pests. Some species of fungi are able to suppress the growth of insects and nematodes that may cause harm to agricultural crops. Typically the fungi that can have such impacts are part of the group called hyphomycetes.