how are viruses, bacteria, protozoans, and fungi helpful and harmful?

Question

at least one example of how they are helpful and one for how they are harmful for each please.

Answer 1

Viruses ---- Viruses are important to the study of molecular and cellular biology as they provide simple systems that can be used to manipulate and investigate the functions of cells. The study and use of viruses have provided valuable information about many aspects of cell biology. For example, viruses have simplified the study of genetics and helped human understanding of the basic mechanisms of molecular genetics, such as DNA replication, transcription, RNA processing, translation, protein transport, and immunology.

Geneticists regularly use viruses as vectors to introduce genes into cells that they are studying. This is useful for making the cell produce a foreign substance, or to study the effect of introducing a new gene into the genome. In similar fashion, virotherapy uses viruses as vectors to treat various diseases, as they can specifically target cells and DNA. It shows promising use in the treatment of cancer and in gene therapy.

viruses cause several diseases.Examples of common human diseases caused by viruses include the common cold, the flu, chickenpox and cold sores. Many serious diseases such as Ebola, AIDS, avian flu and SARS are also caused by viruses.

Bacteria ---- Bacteria, often Lactobacillus in combination with yeasts and molds, have been used for thousands of years in the preparation of fermented foods such as cheese, pickles, soy sauce, sauerkraut, vinegar, wine and yoghurt.The ability of bacteria to degrade a variety of organic compounds is remarkable and has been used in waste processing and bioremediation. Bacteria capable of digesting the hydrocarbons in petroleum are often used to clean up oil spills.In the chemical industry, bacteria are most important in the production of enantiomerically pure chemicals for use as pharmaceuticals or agrichemicals.Because of their ability to quickly grow and the relative ease with which they can be manipulated, bacteria are the workhorses for the fields of molecular biology, genetics and biochemistry.

Pathogenic bacteria are a major cause of human death and disease and cause infections such as tetanus, typhoid fever, diphtheria, syphilis, cholera, food-borne illness, leprosy and tuberculosis. Bacterial diseases are also important in agriculture, with bacteria causing leaf spot, fireblight and wilts in plants, as well as Johne's disease, mastitis, salmonella and anthrax in farm animals.

Protozoans ---- Some protozoans are harmful to man as they can cause serious diseases.Protozoan parasites like plasmodium causes malaria, Trypanosoma causes trypanosomiasis,Leishmania causes leishmaniasis and other diseases.
Others are helpful because they eat harmful bacteria and are food for fish and other animals.As predators upon unicellular or filamentous algae, bacteria, and microfungi, protozoa play a role both as herbivores and as consumers in the decomposer link of the food chain. Protozoa also play a vital role in controlling bacteria population and biomass. As components of the micro- and meiofauna, protozoa are an important food source for microinvertebrates.

Fungi ----- One of the most important things fungi do is something that might not be obvious at first. Because fungi often feed on once-living things, they help break down materials and return them to the earth so other organisms can use them again. Without fungi and other decomposers, dead plants and animals would just lie there forever, so making things rot is a public service! Fungi, the third kingdom of living things, are very important to all life on earth.yeast (Saccharomyces)is used as bakers yeast.Mushrooms are useful for humans.

Fungi are definitely the most widespread and destructive parasites of trees. Often they remain semi-dormant living on dead host tissue in the soil, waiting. Shoe-string root-rot, Armillaria mellia, one of the most ubiquitous fungal pathogen of our forests, is such a parasite/saprophyte.Some fungi also cause the annoying diseases of athletes foot and ringworm.

Answer 2

virus is helpful: ‘cross protection’. An example is the control of very damaging citrus tristezia disease in Brazil by inoculation of young trees with mild isolates of citrus tristezia virus. In the case of dahlias, cross protection is at present problematic because a virus strain may be mild in one cultivar but severe in another.

virus is harmful: pick a virus that is nasty and mutates a lot...pick flu. or HIV.

helpful bacteria: Rhizobium - Nitrogen is essential for all life on this planet, but most of it is in the air, making up about 78% of the earth's atmosphere. Bacteria are the only organisms capable of taking gaseous nitrogen and combining it with hydrogen to make ammonia. So nitrogen-fixing bacteria are an essential part of all ecosystems

harmful bacteria: bacteria can be harmful when food is contaminated with it. Salmonella, Shigella, E. coli are all good examples of this.

protozoa: helpful - Most protozoa are helpful in that they are important in lower levels of the food chain. They provide food for living things such as snails, clams, and sponges.

protozoa: harmful - Among the more common of these cysts is the one which carries the waterborne disease, amoebic dysentery. In addition, Giardia lamblia and cryptosporidium are a cause of acute gastrointestinal illness, the most frequently diagnosed waterborne illness. Cryptosporidium is a major cause of severe diarrhea in children. Giardiasis is usually linked to unfiltered surface water that has not been disinfected sufficiently. Other protozoa found in water supplies are microsporidium, toxoplasma and cylclospora.

fungi: helpful - edible fungi can be used as food. and a yeast fungus called Saccharomyces cereviseae is used to make the alcohol in beer. This same fungus is used when we make bread--without its help, we would have flat bread.

fungi: harmful - Bad fungus is just good fungus trying to do its job way too early to an organism. Most commonly, fungi cause something to happen on the skin of animals or people. This is sometimes called Ringworm, but there is no worm involved! Ringworm can also be called Tinea or Dermatomycosis.


I got all this off of the internet so you're gonna want to put these into your own words unless you want to risk getting tagged for plagerism.