Question: Virus is a small infectious agent that replicates only in the-
(a) Water
(b) Air
(c) Nitrogen
(d) Living cells of an organism
Answer: (d)
Related facts:
- For the first time researchers of USA have observed the direct images of the formation of individual viruses.
- The research provided a detailed view of mechanism with which the particles self – assembled to form a parasite. The study was performed on single stranded RNA virus.
- Single-stranded RNA viruses are the most abundant type of virus on the planet that is responsible for various diseases like the West Nile fever, gastroenteritis, hand, foot, and mouth disease, polio, and the common cold.
- This is an advance discovery that may help humankind to find new treatment approaches for viral diseases.
- It should be known that a virus is a small infectious agent that replicates only inside the living cells of an organism.
- The study, published in the journal PNAS, looked at the formation of single-stranded RNA viruses.
- To unravel this mystery, the researchers used a viewing technique known as interferometric scattering microscopy, in which the light scattered by an object created a dark spot in a larger field of light.
- The technique, the study noted, does not show the virus’ structure, but reveals its size and how that changed with time.
- According to the present study the virus was about 30 nanometers in diameter (thousands of times smaller than the width of a single human hair), and had one piece of RNA with about 180 identical proteins.
- The researchers explained that the proteins arranged themselves into hexagons and pentagons to form a soccer-ball-like enveloping structure around the RNA, called a capsid.
- The researchers mentioned that until now, scientists had not been able to observe how proteins formed the capsid structure in real time since the parasites and their components were very small, and their interactions were very weak.
- When the researchers, attached viral RNA strands to a medium, and flowed proteins over the surface, they could see dark spots appear and grow steadily until they were the size of full-grown viruses.
- As the researchers recorded the intensities of the growing spots, they could determine how many proteins were attaching to each RNA strand over time.