information bacteria ? their classification? their uses?

Question

how are bacteria ?where do they live ? what do they eat ?what is there use ? how r they harmfull?

Answer 1

BACTERIA BELONG TO THE THALLOPHYTA GROUP.THEY ARE THE SIMPLEST LIVING ORGANISMS.BACTERIA OCCUR VERYWHERE,IN WATER,IN THE AIR & IN THE BODIES OF DEAD & LIVING PLANTS & ANIMALS.THE BACTERIA ARE NON GREEN UNICELLULAR PLANTS WHICH ARE VISIBLE ONLY UNDER A MICROSCOPE.BACTERIA ARE MEASURED IN MILLIMICRONS.THERE ARE MANY DIFFERENT KINDS OF BACTERIA.THEY ARE CLASSIFIED DEPENDING ON THE BASIS OF SHAPE,FLAGELLA,NUTRITION & MODE OF RESPIRATION.

THEY ARE USEFUL IN CLEANING THE ENVIRONMENT BY EATING THE DEAD & DECAYING ORGANIC MATTERS.SOME BACTERIA ARE HARMFUL AS THEY CAUSE DISEASES LIKE TYPHOID,TETANUS,TUBERCLOSIS,CITRUS CANKER,CABBAGE ROT,ETC.,THESE ARE CAUSED BY PATHOGENIC BACTERIA.

Answer 2

The Kingdom Prokarya or Bacteria are distinguished from the life forms in all other kingdoms in that they do not have a membrane bound nucleus containing the genetic material of the cell. They are called "prokaryotes". The genetic material is simply found in strands ("plasmids") within the cell's cytoplasm. Note that what was previously called blue green algae are now classified as cyanobacteria because they are prokaryotes. Since they are so different from all other life, under the five kingdom system, Bacteria also comprise the Superkingdom Prokarya.

The cells of life forms in the other four kingdoms are classified as "eukaryotes" and have a nucleus in which the genetic material is organized on "chromosomes" within a cellular nucleus. These four kingdoms comprise the Superkingdom Eukarya. Besides the presence or absence of a nucleus, there are other major differences between prokaryotes and eukaryotes. For example, Bacteria are all over the map in whether they utilize oxygen or another gas such as nitrogen or methane. Some cannot even tolerate oxygen—for these "anaerobic" Bacteria, oxygen is a poison. Almost all eukaryotes are aerobes—they need oxygen to live. That some Bacteria require an oxygen-free environment harkens back to the earth's earliest times and suggest their ancient origin.
Bacteria are so widespread that it is possible only to make the most general statements about their life history and ecology. They may be found on the tops of mountains, the bottom of the deepest oceans, in the guts of animals, and even in the frozen rocks and ice of Antarctica. One feature that has enabled them to spread so far, and last so long is their ability to go dormant for an extended period.

Answer 3

In addition to information in the answer above:

Some of the free-living bacteria are photosynthetic (the cyanobacteria that used to be called blue-green algae) and some are chemosynthetic (using energy from inorganic molecules to build their own organic food molecules).

Bacteria are commonly classified into two kingdoms: Kingdom Eubacteria includes most commonly known bacteria, and Kingdom Archaebacteria includes bacteria that live in harsh conditions such as oxygen-free environments, hot and acidic waters, and hypersaline environments. The Archaebacteria were once classified with Eubacteria in a single kingdom, Monera, but biochemical differences are great enough that Kingdom Monera was subdivided a few years ago. The "domain" system of classifying suggests placing the bacteria into Domain Archaea and Domain Bacteria, with all the rest of the living organisms in Domain Eukarya.

Another harmful effect of bacteria is that some are denitrifying bacteria, taking nitrogen from the soil and releasing it to the air.

Another beneficial effect is that the cyanobacteria release oxygen during photosynthesis.

Answer 4

For knowing about classification of bacteria refer BERGYE'S MANUAL.Bacteria are eubiquitous(present every where on earth).they are neccesary evils.they are both usefull aswell as harm full.a nuber biological processes like the fermentation and biogas production take place only with help of bacteria.they even cause a number of diseases .so knowledge on bacteria is compulsory fro biologist

Answer 5

Bacteria are micro organisms,found every where.they are unicellular,cell wall made up of chitin,true nucleus is absent, cellular organelles are absent except ribosomes,DNA is the genetic material.
some are free living,some are saprophytes,some are parasites,some are symbiont.
uses-preparing curd,vinegar,antibiotics,curing tea&leather
they the natural scavengers,even helps in nitrogen fixing.
harmful effects- spoil the food,cause animal disease like Anthrax,human diseases like.diphtheria,cholera,dysentery. pneumonia,tuberculosis.

Answer 6

Bacteria [pl. of bacterium], microscopic unicellular prokaryotic organisms characterized by the lack of a membrane-bound nucleus and membrane-bound organelles. Once considered a part of the plant kingdom, bacteria were eventually placed in a separate kingdom, Monera. Bacteria fall into one of two groups, Archaebacteria (ancient forms thought to have evolved separately from other bacteria) and Eubacteria. A recently proposed system classifies the Archaebacteria, or archaea, and the Eubacteria as major groupings (sometimes called domains) above the kingdom level.
Bacteria were the only form of life on earth for 2 billion years. They were first observed by Antony van Leeuwenhoek in the 17th cent.; bacteriology as an applied science began to develop in the late 19th cent. as a result of research in medicine and in fermentation processes, especially by Louis Pasteur and Robert Koch.

Bacteria are remarkably adaptable to diverse environmental conditions: they are found in the bodies of all living organisms and on all parts of the earth—in land terrains and ocean depths, in arctic ice and glaciers, in hot springs, and even in the stratosphere. Our understanding of bacteria and their metabolic processes has been expanded by the discovery of species that can live only deep below the earth's surface and by species that thrive without sunlight in the high temperature and pressure near hydrothermal vents on the ocean floor. There are more bacteria, as separate individuals, than any other type of organism; there can be as many as 2.5 billion bacteria in one gram of fertile soil.

Characteristics-

Bacteria are grouped in a number of different ways. Most bacteria are of one of three typical shapes—rod-shaped (bacillus), round (coccus, e.g., streptococcus), and spiral (spirillum). An additional group, vibrios, appear as incomplete spirals. The cytoplasm and plasma membrane of most bacterial cells are surrounded by a cell wall; further classification of bacteria is based on cell wall characteristics (see Gram's stain). They can also be characterized by their patterns of growth, such as the chains formed by streptococci. Many bacteria, chiefly the bacillus and spirillum forms, are motile, swimming about by whiplike movements of flagella; other bacteria have rigid rodlike protuberances called pili that serve as tethers.

Some bacteria (those known as aerobic forms) can function metabolically only in the presence of free or atmospheric oxygen; others (anaerobic bacteria) cannot grow in the presence of free oxygen but obtain oxygen from compounds. Facultative anaerobes can grow with or without free oxygen; obligate anaerobes are poisoned by oxygen.

Reproduction-

In bacteria the genetic material is organized in a continuous strand of DNA. This circle of DNA is localized in an area called the nucleoid, but there is no membrane surrounding a defined nucleus as there is in the eukaryotic cells of protists, fungi, plants, and animals (see eukaryote). In addition to the nucleoid, the bacterial cell may include one or more plasmids, separate circular strands of DNA that can replicate independently, and that are not responsible for the reproduction of the organism. Drug resistance is often conveyed via plasmid genes.

Reproduction is chiefly by binary fission, cell division yielding identical daughter cells. Some bacteria reproduce by budding or fragmentation. Despite the fact that these processes should produce identical generations, the rapid rate of mutation possible in bacteria makes them very adaptable. Some bacteria are capable of specialized types of genetic recombination, which involves the transfer of nucleic acid by individual contact (conjugation), by exposure to nucleic acid remnants of dead bacteria (transformation), by exchange of plasmid genes, or by a viral agent, the bacteriophage (transduction). Under unfavorable conditions some bacteria form highly resistant spores with thickened coverings, within which the living material remains dormant in altered form until conditions improve. Others, such as the radioactivity-resistant Deinococcus radiodurans, can withstand serious damage by repairing their own DNA.

Nutrition-

Most bacteria are heterotrophic, living off other organisms. Most of these are saprobes, bacteria that live off dead organic matter. The bacteria that cause disease are heterotrophic parasites. There are also many non-disease-causing bacterial parasites, many of which are helpful to their hosts. These include the “normal flora” of the human body.

Autotrophic bacteria manufacture their own food by the processes of photosynthesis and chemosynthesis (see autotroph). The photosynthetic bacteria include the green and purple bacteria and the cyanobacteria. Many of the thermophilic archaebacteria are chemosynthetic autotrophs.

Beneficial Bacteria-

Harmless and beneficial bacteria far outnumber harmful varieties. Because they are capable of producing so many enzymes necessary for the building up and breaking down of organic compounds, bacteria are employed extensively by humans—for soil enrichment with leguminous crops (see nitrogen cycle), for preservation by pickling, for fermentation (as in the manufacture of alcoholic beverages, vinegar, and certain cheeses), for decomposition of organic wastes (in septic tanks, in some sewage disposal plants, and in agriculture for soil enrichment) and toxic wastes, and for curing tobacco, retting flax, and many other specialized processes. Bacteria frequently make good objects for genetic study: large populations grown in a short period of time facilitate detection of mutations, or rare variations.

Pathogenic Bacteria-

Bacterial parasites that cause disease are called pathogens. Among bacterial plant diseases are leaf spot, fire blight, and wilts; animal diseases caused by bacteria include tuberculosis, cholera, syphilis, typhoid fever, and tetanus. Some bacteria attack the tissues directly; others produce poisonous substances called toxins. Natural defense against harmful bacteria is provided by antibodies (see immunity). Certain bacterial diseases, e.g., tetanus, can be prevented by injection of antitoxin or of serum containing antibodies against specific bacterial antigens; immunity to some can be induced by vaccination; and certain specific bacterial parasites are killed by antibiotics.

New strains of more virulent bacterial pathogens, many of them resistant to antibiotics, have emerged in recent years. Many believe this to be due to the overuse of antibiotics, both in prescriptions for minor, self-limiting ailments and as growth enhancers in livestock; such overuse increases the likelihood of bacterial mutations. For example, a variant of the normally harmless Escherichia coli has caused serious illness and death in victims of food poisoning..