Kingdom Monera Protoctista and Fungi: Beneficial and Harmful Bacteria (For CBSE, ICSE, IAS, NET, NRA 2022)

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Beneficial and Harmful Bacteria

Diseases Caused by Bacteria:

Image Showing Diseased Caused by Bacteria
Name of BacteriumDiseases Caused
1. Vibrio choleraeCholera
2. Salmonella typhiTyphoid
3. Clostridium tetaniTetanus
4. Corynebacterium diphtheriaeDiphtheria
5. Mycobacterium tuberculosisTuberculosis
6. Mycobacterium lepraeLeprosy
7. Streptococcus pneumoniaePneumonia
8. Yersinia pestisPlague

Beneficial Activities of Bacteria:

Image Showing Beneficial Activies of Bacteria
Name of bacteriunActivities
1. RhizobiumFound in roots of legumes, (Peas, grams,

Pulses etc.) fixes atmospheric nitrogen as ammonia, which is then converted into useful amino acid.

2. AzotobacterMakes the soil fertile. It fixes atmospheric nitrogen in the soil.
3. StreptomycetesProduces Streptomycin antibiotic.
4. LactobacillusFerments lactose (milk sugar) to lactic acid. This helps in setting of milk into curd.
5. Methanogenic bacteriaSewage treatment
6. BifidobacteriumB. longum and B. infantis help prevent diarrhea, candidiasis, and other yeast infections in infants and children.
7. Escherichia coli (E. coli)Produce vitamin K and biotin which are essential for a variety of cellular processes.


Cyanobacteria are also called as blue green algae are relatively simple, primitive life forms closely related to bacteria. Typically, larger than bacteria, they photosynthesize like algae. Cyanobacteria contain a characteristic pigment (phycocyanin) which gives the group their blue-green coloration. Cyanobacteria are also responsible for many of the Harmful Algal Blooms (HABs) that cause ecological, economical and public health concerns in waterways, many times through the production of cyanotoxins.

Image Showing Cyanobacterial Vegetative Cell

Differences between Bacteria and Cyanobacteria

Image Showing Difference between Bacteria and Cyanobacteria
Smaller cellsComparatively larger cells
May have flagellaDo not have flagella
Some bacteria (green) carry out photosynthesis in a different way and do not release oxygenThey all carry out photosynthesis in the usual manner as in green plants and release oxygen
Sexual reproduction by conjugationConjugation has not been observed
Reserve food is GlycogenReserve food is Cyanophycean starch
Nutrition may be autotrophic or heterotrophicNutrition is autotrophic
Spore formation is endogenousSpore formation is not endogenous
Photosynthetic pigments are bacteriochlorophyllPhotosynthetic pigments is chlorophyll ‘a’
Heterocyst is absentHeterocyst is present
Composition of cell wall is Glycolipids and peptidoglycanComposition of cell wall is Cellulose and pectin


Kingdom Monera includes two groups: Archaebacteria and Eubacteria. They can only live in areas without oxygen. Main types of Archaebacteria are.

  • Methanogens: live in oxygen free environments and they produce Methane gasses and found in marshes, lake sediments, and digestive tracts of animals
  • Thermoacidophilic: Autotrophic producer, live in hot areas and water is a very hot/acidic sulfur spring
  • Halophilic: live in water with a very high concentration of salt and found in Utah՚s Great Salt Lake and The Dead Sea in the Middle East.

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