What is life? How is the living different from the non living? One could say we breath air, we eat food, we live our lives and reproduce and rocks don't, so that that separates us, but what is life in on itself?
A set of biological processes and structures? One thing universal to all (known) forms of life is a set of molecular instructions- The genome as biologists call it. Instructions which command all functions of a cell, The DNA. The DNA is a very huge sequence of nucleotides Adenine (A) Thymine (T) Guanine(G) and Cytosine (C) the- ATGC. The basic units of the 'Code of life'
The english alphabet has 26 letters yes? 26 symbols which when put in a very particular sequence represent some information. If you want to represent the information of the apple then you will spell it as the sequence A-P-P-L-E. Now imagine a language with only 4 letters. Only 4 letters to represent any piece of information you want to convey. Only these four letters - ATGC. This is the language of Life, this is the symphony of life, the magna opera of the 'Composer'...if..he exists.
It's not too hard to imagine. Take your telephone number for example, it is a sequence of 10 digit code which represents the information which will dial to your phone. Just a sequence of 10 symbols to represent the information to contact you among billions of people. That is the language of telecommunications.
Similarly the sequence of these nucleotides can be millions and billion of digits long. It can go on and on... AGTTACCGAA... Absolutely randomly.
And sometimes... not absolutely randomly.
You see, the central dogma of life dictates the very essence of our existence. There are 3 basic things which are essential to life and the central dogma.
1. DNA
2. RNA
3. Proteins
The DNA as we discussed has has the sequence of information.
The RNA- Ribonucleic acid, is another type of Nucleic acid other than the DNA with nucleotides. The function of the Ribonucleotide is to read the code on the DNA. It is also a chain of nucleotide exactly complimentary to what it read on the DNA. (Transcription)
The RNA then form another long chain molecule, the protein. (Translation)
Ok now, now, Anybody who is familiar with this level of biology will say, 'hey we know that already' and anybody who isn't has no idea what I am talking about. If you want to know more about the central dogma, look it up on wikipedia...you will literally know the basics of how life works. Literally.
Central Dogma of Biology
Just remember, If you want to send a letter, your 26 letter sequence language is the DNA, the postman is the RNA and the recipient is the PROTEIN which follows whatever instruction you give. Ok? Ok.
Ok back to proteins, proteins form....EVERYTHING. All your biological cells, tissues, organs are formed by proteins. All the physiological reactions happening in your body right now is because of enzymes (they are proteins). Your nails are proteins, your hair, your skin, a plant, a bacteria. A protein transports oxygen to your system (Haemoglobin), a protein helps you digest something. Any bodily function, you name it, done by a protein.
So how does all this play into life? This central dogma is the main reason why the living posses a very complex set of Metabolic reactions which govern everything from body temperature to production of alcohol from yeast.
Ok, so life contains DNA. And the inanimate objects don't. Is that what makes life...life?
Well, most of them. But there are entities which are in the blurred lines between the Living and the nonliving...in a way they are both living...and nonliving.
Wait what? They are both Living and Non-Living?
Yes. Viruses. Biologists debate whether they should be classified as the living or the non living.
Why? Because Viruses have DNA (some have RNA as their genome and they called retro-viruses example HIV) but they lack any metabolic functions of their own. What they essentially are is a capsule of protein covering their genome (DNA or RNA).
Viruses integrate their genome into a host cell of a bacteria, plant or an animal. They literally 'hijack' the cell's central dogma, produces proteins of its own which form the capsule and a thousand more copies of itself which ultimately burst the cell open and thousands of viruses are made.
Viruses do have a genome, but they lack a metabolic machinery of their own...so are the living or are they...just a bunch of protein coated nucleic acid molecules?
They are so simple that they blur the line between a 'molecule' and an 'organism'
So the whole concept of life is slightly ambiguous and we can't have a perfectly rigid definition of life.
But we can safely say that any kind of life has nucleic acid (DNA or RNA) and with that and their complex biochemical metabolic machinery that entity is called ... the living.
Or can we?
Must life have these complex biological systems?
Must life be...carbon ...based?
What if, in a 100 years we develop Artificial Intelligence so advanced that it is nearly identical to a human mind? That it would able to think like a human and feel human emotions. That it will feel pain and happiness just like humans? That it will have sentience? That it will be able to copy its code and reproduce just like living organisms do?
Will that AI be considered living?
It doesn't have carbon based code. It has a binary code.
It doesn't have any biological molecule.
Yet...it lives.
It's ...Alive.
Will it be a silicon based life instead of a carbon based life form? If so, will it be ethical to switch off or delete it's files? Will that be considered death?
If we are the 'Composers' of this grand symphony of this computer code...Did we create life? We would be their creators? Their Gods?
We don't know.
Life... doesn't have rigid definitions. Not anymore.
But does it matter how humans define it? Will it change anything if we are able to successfully define life? The universe's indifference to us will continue. Is the concept of life be just a construct of human mind trying to justify it's existence or is it just a complex organisation of matter?
After all, we just know life exists and fulfilling it's purpose.
Wait.
What is the purpose of life then?
Why life exists?
A set of biological processes and structures? One thing universal to all (known) forms of life is a set of molecular instructions- The genome as biologists call it. Instructions which command all functions of a cell, The DNA. The DNA is a very huge sequence of nucleotides Adenine (A) Thymine (T) Guanine(G) and Cytosine (C) the- ATGC. The basic units of the 'Code of life'
It's not too hard to imagine. Take your telephone number for example, it is a sequence of 10 digit code which represents the information which will dial to your phone. Just a sequence of 10 symbols to represent the information to contact you among billions of people. That is the language of telecommunications.
Similarly the sequence of these nucleotides can be millions and billion of digits long. It can go on and on... AGTTACCGAA... Absolutely randomly.
And sometimes... not absolutely randomly.
You see, the central dogma of life dictates the very essence of our existence. There are 3 basic things which are essential to life and the central dogma.
1. DNA
2. RNA
3. Proteins
The DNA as we discussed has has the sequence of information.
The RNA- Ribonucleic acid, is another type of Nucleic acid other than the DNA with nucleotides. The function of the Ribonucleotide is to read the code on the DNA. It is also a chain of nucleotide exactly complimentary to what it read on the DNA. (Transcription)
The RNA then form another long chain molecule, the protein. (Translation)
Ok now, now, Anybody who is familiar with this level of biology will say, 'hey we know that already' and anybody who isn't has no idea what I am talking about. If you want to know more about the central dogma, look it up on wikipedia...you will literally know the basics of how life works. Literally.
Central Dogma of Biology
Just remember, If you want to send a letter, your 26 letter sequence language is the DNA, the postman is the RNA and the recipient is the PROTEIN which follows whatever instruction you give. Ok? Ok.
Ok back to proteins, proteins form....EVERYTHING. All your biological cells, tissues, organs are formed by proteins. All the physiological reactions happening in your body right now is because of enzymes (they are proteins). Your nails are proteins, your hair, your skin, a plant, a bacteria. A protein transports oxygen to your system (Haemoglobin), a protein helps you digest something. Any bodily function, you name it, done by a protein.
So how does all this play into life? This central dogma is the main reason why the living posses a very complex set of Metabolic reactions which govern everything from body temperature to production of alcohol from yeast.
Ok, so life contains DNA. And the inanimate objects don't. Is that what makes life...life?
Well, most of them. But there are entities which are in the blurred lines between the Living and the nonliving...in a way they are both living...and nonliving.
Wait what? They are both Living and Non-Living?
Yes. Viruses. Biologists debate whether they should be classified as the living or the non living.
Why? Because Viruses have DNA (some have RNA as their genome and they called retro-viruses example HIV) but they lack any metabolic functions of their own. What they essentially are is a capsule of protein covering their genome (DNA or RNA).
Viruses integrate their genome into a host cell of a bacteria, plant or an animal. They literally 'hijack' the cell's central dogma, produces proteins of its own which form the capsule and a thousand more copies of itself which ultimately burst the cell open and thousands of viruses are made.
Viruses do have a genome, but they lack a metabolic machinery of their own...so are the living or are they...just a bunch of protein coated nucleic acid molecules?
They are so simple that they blur the line between a 'molecule' and an 'organism'
So the whole concept of life is slightly ambiguous and we can't have a perfectly rigid definition of life.
But we can safely say that any kind of life has nucleic acid (DNA or RNA) and with that and their complex biochemical metabolic machinery that entity is called ... the living.
Or can we?
Must life have these complex biological systems?
Must life be...carbon ...based?
What if, in a 100 years we develop Artificial Intelligence so advanced that it is nearly identical to a human mind? That it would able to think like a human and feel human emotions. That it will feel pain and happiness just like humans? That it will have sentience? That it will be able to copy its code and reproduce just like living organisms do?
Will that AI be considered living?
It doesn't have carbon based code. It has a binary code.
It doesn't have any biological molecule.
Yet...it lives.
It's ...Alive.
Will it be a silicon based life instead of a carbon based life form? If so, will it be ethical to switch off or delete it's files? Will that be considered death?
If we are the 'Composers' of this grand symphony of this computer code...Did we create life? We would be their creators? Their Gods?
We don't know.
Life... doesn't have rigid definitions. Not anymore.
But does it matter how humans define it? Will it change anything if we are able to successfully define life? The universe's indifference to us will continue. Is the concept of life be just a construct of human mind trying to justify it's existence or is it just a complex organisation of matter?
After all, we just know life exists and fulfilling it's purpose.
Wait.
What is the purpose of life then?
Why life exists?
