1.3 VIRUSES

1.3 VIRUSES

  Viruses are so small that they cannot be observed with light microscope but can be studied with electron microscope and biochemical tests. 

VIRUS IS A LATIN WORD WHICH MEANS POISON

Viruses are of different shapes, some are rounded, few are rod-shaped and a few polyhedral while some viruses look like tadpoles.

              Structurally viruses are made up of nucleic acid and proteins. Viruses consist of two parts, an outer ‘coat’ and inner ‘core’. The coat is composed of protein and the core is made up of DNA or RNA.

  Viruses are considered as a link between living and non-living things. They reproduce like living organisms and non-living organisms, found also in the form of crystals.

     All viruses are parasites and obtain their food from other living organisms. Viruses in living organisms are transmitted in variety of ways i.e. by air, contaminated water and food, through insects, droplets produce on coughing and sneezing and through contact.

Viruses produce many diseases in plants and animals. In human beings, viruses produce Measles, Influenza, Cold, Small pox, Polio, Hepatitis B & C, Cancer, AIDS and SARS. Viruses usually cause diseases in the plants of tobacoo, potato, tomato and cabbage etc.

DO YOU KNOW?

SARS (Severe Acute Respiratory Syndrome) It is a pneumonia like viral disease, in which at first temperature of patient rises. He feels cold, irritation in throat, difficulty in breathing and suffocation. Some times death can occur.