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Bacteria are microscopic organisms which have the ability to survive in very diverse environments.

Bacteria are microscopic organisms which have the ability to survive in very diverse environments. The bacteria are known to be both beneficial and harmful. They have a simple structure with very few cell organelles and no nucleus is present. The bacteria have two protective coverings which surround them and they are the outer cell wall and inner cell membrane. It has been found that some of the bacteria use capsule to be covered up, whereas, some other, for instance Mycoplasma do not possess a cell wall.

The surface of the bacteria is covered by shirt whip – like extensions called pili. The long which like structure that extends from the body is called flagella. The bacteria are known to demonstrate both autotrophic and heterotrophic modes of nutrition. Inorganic substances provide nutrition to the autotrophic bacteria. They draw hydrogen and carbon from the carbon dioxide present in the atmosphere, hydrogen, hydrogen sulphide and ammonia. The heterotrophic bacteria in the other hand are dependent on external organic materials for deriving their food. They can either be saprotrophs, symbionts and / or parasites.

The bacteria have different shapes and they are discussed below:

Bacilli  – These bacteria are rod – shaped and may or may not have flagella.

Cocci  – The bacteria are either oval or spherical in shape. They can be staphylococcus (in clusters), streptococcus (in chains), tetracoccus (in fours),

diplococcus (in pairs) and micrococcus (single).

Vibrios  – These bacteria are kidney – shaped or comma shaped bacteria and the flagella is found at only one or sometimes at both ends.

Spirillum  – The spirillum are the spiral or coiled shape bacteria. These bacteria are rigid due to the spiral structure and flagella may be present only at one or at both ends.

Filament  – In this case, the body are found to have small filaments like the fungal mycelia.

Budded  – The body of this bacteria are swollen at places.

Stalked  – This type of bacteria possesses a stalk in its body.

The kingdom Monera has been divided into three sub – kingdoms known as Cyanobacteria, Eubacteria and Archaebacteria.

Archaebacteria  – in the most extreme habitats the Archaebacteria are found. They are the most ancient group of bacteria living. Their habitat includes halophiles i.e., salty areas, thermoacidophiles i.e., hot springs and methanogens i.e., marshy areas. The structures of their cell walls are found to be different from other groups of bacteria and this helps them in surviving in such conditions. The mode of nutrition among Archaebacteria is autotrophic and the nucleotide sequences of their t – RNA and r – RNA are unique.

Eubacteria  – This group of bacteria are also termed as “true bacteria”. They have rigid cell walls which are formed of peptidoglycans. The mode of locomotion is flagella. A few bacteria are known to contain short appendages on the surface of the cell and are known as pili.

Cyanobacteria  – The Cyanobacteria are also known as blue – green algae and mode of nutrition is photosynthesis. These types of bacteria are commonly available in the aquatic regions and some can even fix atmospheric nitrogen. Anabaena is a type of Cyanobacteria.

Monera is a kingdom comprised of prokaryotes that are single – celled organism without a true nucleus.

The organisms have naked DNA which creates a clump which is termed as the nucleoid.

The organisms belonging to this kingdom can be found within animal bodies, plants, deep oceans and hot springs.

Organisms are found to be autotrophic who prepare their own food either by chemosynthesis or by photosynthesis.

Bacteria are microscopic organisms which have the ability to survive in very diverse environments.

The kingdom Monera is broadly classified into three sub – kingdoms known as Archaebacteria, Eubacteria and Cyanobacteria.

In biology, monera is a kingdom comprised of prokaryotes that are single – celled organism without a true nucleus. This kingdom monera is one of the earliest groups of organism on earth. In this particular kingdom, it has been observed that the organisms have naked DNA which creates a clump which is termed as the nucleoid. The organisms belonging to the other kingdom are known to have DNA enclosed in a nucleus. The organisms belonging to the kingdom monera are prokaryotes, like bacteria and do not have membrane bound organelles. The organisms are microscopic and are generally found living in moist environments. For instance, the organisms belonging to this kingdom can be found within animal bodies, plants, deep oceans and hot springs.

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