There is no consensus on what is and what isn’t alive. One definition describes a living thing as having an organised structure, requiring energy, adapting to environmental change and responding to stimuli. So far a rock will satisfy those criteria but the definition goes on to include reproduction, growth, movement, metabolism and death.
Single celled bacteria can reproduce and are regarded as living. Also classed as living are archaea; they have similarities to bacteria and like bacteria their cells are classified as of type prokaryote. Archaea have different cell walls, can live in extreme temperatures where bacteria would not survive, are unaffected by antibiotics and have three enzymes able to synthesise RNA molecules; bacteria has only one. The other major and larger cell type is that of eukaryotes and includes all animals and plant life and of course us humans.
So how should we see the Covid 19 virus. Is it alive or not?
In shape it is spherical and about 80 millionths of a millimetre in diameter. It has encased in its porous membrane the largest single RNA (ribonucleicacid) of any viruse being composed of over 26,000 nucleotides.
Viruses are much smaller than and not regarded as cells. They are thought of more as packages of proteins and nucleic acids. However, their genome of RNA contains the same bases of adenine, guanine, cytosine, but with uracil replacing thymine, as are present in all cell structures. Also like those cell structures there are genetic variations and the structure can evolve and change to better suit its environment. It is thought, for example, that covid 19 learnt to replicate itself faster in bats as bats built up strong antibodies.
Unlike prokaryote and eukaryote cells, viruses have no ribosomes and so cannot make their own proteins. In order to survive and replicate themselves they need to make proteins and this they do by first attaching their spike S protein to ACE 2 receptors of host cells and then opening up that host cell so that the viral RNA can utilise the replication machinery of the host cell. This it does so as to reproduce itself many times over before emerging from the host cell.
I am perhaps a little biased in that I regard all energy desiring atomic energy structures as living. I say that the gravity motion of earth toward the sun is a living desire of earth particles for sun energies and that we are held on the earth by our particle desires for earth energies. So, I do not hesitate to describe the Covid 19 virus structure that is using the energy of its environment to satisfy the energy needs of its particles as living. But what do you think. Do you think that a structure that can take control over our body cells is living?
The covid 19 virus carried on water droplets and gaining access to the Ace 2 receptors in our throats will cause the triggering of anti bodies. They are our structures way of defending themselves. If the viral load is high or the immune system weak the virus may gain access to the more numerous ace 2 receptors in the lungs damaging cells and causing congestion. Sometimes the immune system will respond by going into overdrive and as it does with arthritis start attacking healthy cells with disastrous results.