Question

Write a brief note on harmful activities of bacteria.

Answer 1

Food poisoning → It is the discomfort mainly caused by the toxins                          produced by BACTERIA. Bacteria are the main cause of food poisoning. 
                        
Spoilage of food →  Rotting of vegetables , fruits , meat etc.. are                              caused by saprotropic bacterias that are always present   in the air nd they settle down in the exposed food. 

Spoilage of Domestic Articles ⇒ Bacterias like Cellulomonas  attack                        textiles , leathers , canvas , wood articles nd later it results in the spoilage of all...

Denitrification ⇒ bacterias like PSEUDOMONAS living in water                      logged soil picks up oxygen from the nitrates.. nd ∴ the nitrates changed into gaseous forms of nitrogen .. The harmful effect is that they reduce the usable nitrogen in the soil.

Water pollution ⇒ Some of the bacterias can easily multiply in water                                nd bring abt its pollution
           eg: Vibrio cholerae , Salmonella Typhi etc.

DISEASES ⇒ Most about 90 % of human  diseases are caused by                              bacteria. like Typhoid fever, syphilis, cholera,                                          tuberculosis etc.. 
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       Animal diseases like Anthrax, Black Leg , Brucellosis   etc.. are bacterial infections.  

Bioweapons → All the spores forming pathogenic bacteria ( eg;                                    Bacillus anthrax) can be used as bio weapon for                                   creating terror.
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Answer 2

bacteria are like the main members of the kingdom monera. They occur like almost everywhere on this world. They can thrive in extreme harsh surroundings. It was anton van leeuwenhoek who discovered the bacteria for the first time 
part 1-common ones
* some bacteria break down nitrates and reduce soil fertility ( they are denitryfing baccteria)
* pathogenic bacteria cause several diseases to plants and animals
*som bacteria cause spoilage of food materials 

part 2- diseases 
bacteria is a kinda disease causing pathogen in our society 
* typhoid
    - typhoid is one of the most common diseases in india. From doctors point of view, it is a part of the tropical disease . Typhoid is cause by the bacteria samonella typhi. 
the main problem with this bacteria is that it can affect our intestine and so the symptoms starts from our stomach itselves
                                loss of appetite, weakness followed by stomach pain , constipation etc are the major symptoms .

* pneumonia
  this one affects out lungs and thus causes problem in respiration. 
* tuberculosis 
   it is caused by mycobacterium tuberculosis 
* cholera 
  it is caused by vibrio cholera 
  

diarrhoea, tetanus, syphilis, leprosy, gonorrhoea are other major diseases caused by the bacteria 

part 3-

* nitrifying bacteria like nitrosomonas obtain energy by oxidizing ammonia to nitrite and nitrobacter oxidizing nitrite into nitrate. This process increases fertility. But some kinda denitrifying bacteria oxidizes back these nitrates reducing the fertility of the soil

* methanogens are mainly seen in dung of cows and other such animals. They produces bad smell. Even some of the organic wastes will produce methane gas which is bad to smell


part 4-
* bacterial blight disease is seen in paddy, cotton
*soft rot of turnip is another bacterial disease 
*black rot
*bacterial canker
*wilt disease ( seen in leaves)