Jerry Cowan, age 11, of Claremore, Oklahoma, for his question:
Are viruses living or non living?
A generation ago, opinion was divided. Some scientists suspected that viruses are inorganic, or non living organisms though they did not venture to classify them as plants or animals. Then a couple of years ago, researchers found new evidence that viruses are forms of life. Now it is generally accepted that they are strange and infinitesimal organisms that seem to bear no relationship to the plant or animal worlds.
Living cells come in a multitude of shapes and sizes, each encased in its personal membrane, or cellular wall. The average cell is a mass of jellified protoplasm, embedded with various small granules and seething with the motions of complicated biochemical activities. The key granule is the nucleus, which contains the astounding chemicals that direct and organize these life activities.
A living cell is qualified by the presence of these remarkable nucleic chemicals. The blueprint chemical is known to one and all as DNA. Its coded instructions are transmitted throughout the cell by RNA, the message carrier. Every living plant and animal cell contains its DNA blueprint and the RNA messenger chemical to organize the processes of life.
The average virus is a large molecule stuffed inside a tough protein shell. When the polio virus is magnified 180,000 times by the powerful electron microscope, it looks somewhat like a coin filled with a multitude of fuzzy balls. Its tough shell contains the same key life chemicals found in the nucleus embedded in the cytoplasm of the average living cell.
Without cytoplasm to carry on the processes of life, a virus must operate as a parasite at the expense of normal living cells. Medical researchers have identified more than 50 different viruses that cause specific diseases in animals, plants and people. Recently we learned how some of them do their dirty work.
In normal cells, RNA carries out the orders issued by DNA. The new evidence suggests that a parasitical virus can reverse this chain of command. When it enters a host cell, its RNA issues orders to the DNA of Its host. The DNA blueprint is forced to order its own cell to manufacture copies of the invading virus. Hence, the enemy multiplies and the disease spreads from cell to cell.
These virus activities use and abuse the DNA and RNA processes of life. For this reason they must be rated as living things, though in a special degenerate class of their own.
We now know that viruses are living parasites that require normal living cells to thrive and multiply. When not occupying a host, they become dormant and their tough shells can protect them in this state, in some cases for years. But when these dormant parasites come in contact with a suitable host, they become active. And some are known to use their RNA to reprogram the. host cell's DNA to multiply themselves.