Bacteria are one of the most unique prokaryotic microorganisms in the world. They are found in almost every corner of the planet and in every habitat and even inside other organisms. They are unique in terms of both morphology and composition. Almost one-third of the total cells in our body are that of bacteria. Bacteria belong to the Kingdom Monera and they are broadly divided into many types depending upon various characteristics. Mainly, bacteria are grouped into two main categories that are archaebacteria and cynobacteria but in terms of their shape, they are divided into four categories: coccus (spherical), bacillus (rod shaped), vibrium (comma shaped) and spirillum (spiral).
Important characteristics of bacteria
There are various characteristic of the bacteria that make it one of the unique organisms in the planet. Some of the main and common characteristics of the bacteria are as follow
Bacteria are moistly unicellular and a thin layer of mucilage covers their cell body. Their cell body is well protected by a thick cell wall which is mainly made up of special protein.
Since bacteria are prokaryotic, they lack a well organized nucleus. The genetic material is scattered into the cytoplasm and it is known as nucleotide.
Bacteria contain 70s type of ribosomes and they lack sap vacuoles, mitochondria, Golgi apparatus, plastids and other cell organelles inside their cell body.
Bacteria reproduce asexually through budding, fission and spore formation. There may arise some genetic variation in the progeny due to the present of gene recombination in reproduction.
Bacteria store their food in the form of glycogen and they may have flagella, gliding and flexion for locomotion.
Economic importance of bacteria
Bacteria plays the most important parts as a decomposer of organic remains of the dead plants and animals. They revive the inorganic substances from the dead organisms back in to the nature and continue this cycle creating a balance in nature.
Bacteria that live inside our body protects us from various minor diseases as well as infections and they also release various useful minerals and vitamins such as biotin, potassium, thiamine etc. They also release various enzymes and play an important part in the digestion system of our body and controlling the decaying of undigested food in our body.
There are numbers of bacteria mostly belonging to the genus Streptomyces are uses as antibiotics to protect ourselves from various diseases. One of the best examples is penicillin which was also the first antibiotic in the world. Some other examples are subtilin made from Bacillus subtilis, Terramycin made from Streptomyces rimosus etc.
Some bacteria are used as pollution controllers in nature. Pseudomonas is a bacterium which is used to decompose petroleum waste in petroleum industry and various man-made organic wastes in different industries.Acetobacte aerogens is used to putrefy DDT pesticide.
Bacteria are also used as bio-pesticide to control various insect pests. Bacillus sphericus is sprayed to manage the population of mosquitoes whereas Bacillus popilliae is used to controls the population of Japanese beetles.
Methanogens (belong to archaebacteria) are used to convert biomass (manures) into bio-gas. At first, all the organic wastes including cow dung and human faces are decomposed by anaerobic bacteria in an airtight container and later methanogens convert it into methane gas which is used as fuel.
Bacteria are used in genetic engineering for the production of synthetic insulin, various hormones, enzymes, proteins etc. Agrobacterium tumefaciens is a widely used bacterium for the production of various protein and hormones and Bacillus megatherium is used in the synthesize of B12 vitamin. .
Bacteria such as Bacillus megatherium are widely used to provide particular smell and taste in coffee, caffeine, cocoa and tea in their respective industries and are also used to reduce their bitter taste.
Bacteria plays an important role in the nitrogen fixation and in the nitrogen cycle. Azotobacter, Bacillus, Rhodospirilum and Nostoc are nitrogen-fixing bacteria which directly converts atmospheric nitrogen into ammonia. Nitrosomonas, Nitrococcus convert ammonia into nitrite and Nitrobacter further oxidizes nitrite into nitrate.
Harmful activities of bacteria
Bacteria live as pathogen in both plants and animals and cause a lot of diseases. Vibrio cholera causes cholera in human, Bacillus anthracis causes anthrax in animals such as cattle and sheep and Erwinia amylovora causes fire blight in plants like apple.
Bacteria spoil most of the organic food and also causes food poisoning. Bacteria are present in the air and when they fall over food particle they start to decompose the food particles resulting in spoilage of the food particles.
Many pathogenic bacteria are used as bio-weapon. Spores of pathogenic bacteria are widely used to spread various diseases in the populace.
Various types of bacteria such as Vibrio cholera, Salmonella typhi also causes water pollution. They multiply very rapidly in water where there is abundant of food causing water pollution and making it unfit for economic uses.