WHAT  ARE  VIRUSES ? 


  • Viruses are microscopic parasites generally much smaller than bacteria. They lack the capacity to thrive and reproduce outside of a host body.
  • Viruses are said to be so so small that 500 million rhinoviruses( which cause the common cold ) could fit onto the head of a pin.

  • They are unique because they are only alive and able to multiply inside the cells of other living things.

  • Viruses can infect all type of life forms from animal and plants to microorganisms including bacteria and archaea. 
  • WHERE DO VIRUSES COME FROM?

  • Three main hypothesis have come :

  1. The progressive hypothesis states that viruses are rows from genetic elements that gained the ability to move between cells.
  2. The regressive hypothesis states that viruses are remnants of cellular organisms.
  3. The virus first hypothesis states that virus predate or co evolved with their current Cellular host.

APPLICATIONS OF VIRUSES 

  1. Study and use of viruses have provided valuable information about aspects of cell biology.
  2. Virotherapy involves the use of genetically modified viruses to treat diseases.


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