Life

When someone tells you that there is some chemistry between you, I want you to think about some things. What is life but chemistry. During our primary school science days the teacher once asked me what life was. I couldn't answer and he went ahead and read from a text book that life couldn't be defined, that instead we could talk about the characteristics of living things in an effort to  expound on what life was.
As I have grown older, and as recently as last night I have thought about how I could define life. The latest definition I have is : Life is a series of continuous, coordinated and complex chemical reactions whose aim is (a) to produce macromolecules that when combined and differentiated form tissues and organs, and (b) to produce chemicals to modulate the functions of these tissues and organs.
There are several reasons why I came up with this definition. Firstly everything on earth is made up of elements combined to form molecules of differing complexity and which further combine to form every physical thing on earth. As such if you were to go down to the most basic level, all structures within the body originate from some chemical reaction. Then it gets easy. The body has a template called DNA. DNA's chemical structure is given below:

The long and short of it is that from this amino acids are formed. These amino acids combine to form proteins. They can also combine to form other macromolecules like glyco-proteins etc. The other chemicals needed to form everything else in the body come from food, air or they are synthesized by the body. A dead organism's body cannot support any chemical reaction. Any chemical reactions after an organism dies can be traced back to colonization by other living things e.g. bacteria. Thus it would be correct to say that an animal which is not initiating and continuing any chemical reaction in its body is dead!
We say that we give life when we bear children but think about it. We just provide fully functional ova and sperm to combine so that the fetus can be made. A dead person cannot produce life. We are simply continuing a chemical reaction that started when the first atoms were formed!
I once said that the aim of life is simple; to produce offspring, to get nutrition and to survive. These are the important things that every organism has to do in order to survive. And its not surprising that only an organism whose chemical reactions are intact will accomplish this.
This brings me to a question; are viruses alive? For those not in the microbiological field a virus is a simple thing made up of a coat, nucleic acid and some chemicals. Outside the host cell the virus does nothing, it has no ongoing chemical reaction. It is thus dead. Inside a functional cell it  produces offspring by hijacking the host cells amino acid synthesis, it gets nutrition by utilizing the host cell's chemical constituents to produce offspring and it survives. Thus it is alive.
Please comment on my definition of life.