Virions affect cells on a many different levels. For example, this is how HIV becomes AIDS and how some people can live for decades while infected with HIV and not fall sick. After a while a lysogenic cycle can become a lysic cycle, and that is when the disease starts to have a visible effect on the cells. Those two cycles can merge into one another. This integrated viral nucleic acid does not do any harm to the cell. Their nucleic acid builds itself into cellular DNA and replicates with it. Some other viruses can work in a different way.
Then the cell dies, falls apart and releases the new viruses that can then penetrate into new cells. After this process is done, the new virions form inside a cell. Virus DNA or RNA changes the metabolism of the host cell, so that it starts producing new viral nucleic acids and proteins that build viral capsules. If a virus comes across the right host cell it binds to it and injects its genetic material into the host cell. They also evolve and complete themselves through the process of natural selection. They reproduce and pass their genetic specifications up to the next generation. When inside a host cell or bacteria, they show signs of life. But at the same time, they are also considered to be living organisms. They do not grow or have an active metabolism. They are not considered to be living because they have such a simple structure, only have one nucleic acid, and are not able to move actively by themselves. Image of a recreated 1918 influenza virus via CDC Some viruses have an envelope (lipid membrane) around the capsid that offers extra protection for the nucleic acid. Inside the capsid (protein coat) is nucleic acid that contains genetic information (either DNA or RNA – but never both at the same time, as in other living beings). Virus particles (virions) are made out of two or three parts. Viruses are smaller than bacteria and they are built simpler than any other cells.
They are not alive, nor are they unliving. Life is the process of self-preservation for living beings and can be recognised by life processes such as eating, metabolism, secretion, reproduction, growth, heredity etc. There are some ‘creatures’ present on our planet that cannot be put into either category. Rocks do not reproduce, they do not die, and therefore they were never alive. Have you ever asked yourself, what is it that actually makes us alive? What is it in us that makes us so different from the unliving? What differentiates a man, animal, or tree from a rock or water? If you think about it, you will be able to pinpoint the differences.
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