Virus and bacteria

Virus and bacteria 

‘Virus’ is a minute parasitic organism composed of nucleic acid and protein, which can show few living characteristics while in a living cell.

‘Virus’ means poison. They cannot be seen without electron microscope. Virus particles have no cell wall, plasma membrane, organized nucleus a virus particle cytoplasm etc. So virus body is called acellular. They are composed of only protein coating and nucleic acid (DNA or RNA). A T2 Bacteriophage virus has head, tail and tail fibres. Virus,Ricketsia, Fungi, Bacteria, Algae, and Protozoa etc. are present in our environment in innumerable numbers. Most of them are harmless. Of course some of
them are responsible for producing diseases in human body. Now we will know about few microorganisms

Virus:

These are simplest organisms. Body maily composed of Protein and Nucleic Acid. If Nucleic acid gets out of protein coating they lose all characters of life. But it is interesting that if the constituents are gathered again they got the signs of life again. Virus is true parasite that is they have no existence without living host. Outside of living host they do not show any signs of life.
Virus may be round, rod shaped, tadpole like or bread shaped. Virus causes Pox, Measles, Sneezing, Influenza etc. in human body. Trungro of rice and mosaic diseases of tobacco caused by Virus. Pox, Measles, Sneezing, Influenza etc are airborne diseases

Bacteria: 

We have learnt about bacteria in the previous class, now we are to have a
broader look. Bacteria is non green, unicellular microscopic Organisms with primitive nucleus. Antony von Leuen Hoek found the for the first time. Bacteria cell may be rod shaped, rounded, comma shaped or spiral.
Bacteria can be classified according to their shape as follows
a. Coccus: Rounded shaped bacteria cell
are named as coccus. They remain
singly or in groups. Such as Pneumonia
causing Bacteria.
b. Bacillus: These are elongated rod shaped
bacteria. Tetanus, Blood Dysentery etc are caused by Bacillus.
c. Comma: Shaped like bend rod. Such as Bacteria causing Human Cholera.
d. Spirilum: Spiral Bacteria.

Usefulness of Bacteria: 

• Helps in decomposition of dead bodies and organic wastes.
• Only bacteria fixes nitrogen in the soil.
• Helps in removing jute fibres.
• Used in preparation of curds.
• Preparation of life saving Antibiotics.
• Very much important in Genetic engineering and in laboratory research.