At this very second we all are walking on a tightrope of life and death. We don’t feel it but an incredible amount of work is going on inside us to keep us alive. It is as if we are trying to go down using an escalator which is actually going up. If the escalator took us to the top that means you are dead. And the universe wants you to be dead.
All life is based on cell. A cell is a part of the universe that is just matter and energy but dead. Cells just separated itself for a time being so that it could do whatever it wants to do. Otherwise the universe would love to keep us in a form of energy or matter. When the separation period ends the cell just joins the dead universe again. The universe doesn’t like the fun of being alive and is not a fan of the exciting things that life can do. It would rather be boring as possible with all the matter and energy. This is called entropy.
Living things are always doing something exciting. A cell is filled up of a proteins and simple molecules like water. Thousands of things are happening every second inside our cell to keep it and us alive. To stay alive it has to keep up the activity or else it will reach entropy and again be the boring dead stuff. But for these activities happening inside it, it needs energy. So billions of years ago when the first cellular life was forming on earth, the most important challenge was to find a usable energy. Though not much is known about those first cells but it is expected that they got their energy from simple chemical reactions. And it required an energy transfer system which it got in the form of a molecule ATP- Adenosine triphosphate.
This molecule is very good at accepting and releasing energy. When the cells need energy, it breaks down the ATP and uses its energy to get the work done. This process is crucial to all types of life form on earth including plants, bacteria, and fungi. So no ATP means no life.
The biggest source of energy for us is the sun. Atoms merge inside the sun and radiate photons to the solar system, but this is raw energy and was not usable directly. It took millions of years of evolution for the cell to refine this photon energy to digest it. This is done through photosynthesis. Now the cells could convert the electromagnetic energy to chemical energy which could be stored in ATP. This process got better as some cells could now produce glucose- easier to break down and full of energy. Now some cells took the easy way and decided that instead of doing all the work of photosynthesis it would just eat other cells that did all the work and eat their glucose and ATP. Some cells made energy and some ate them and things went on like this for a pretty long time.
One day a cell ate another cell but did not kill it- instead they became one cell. This change would change earth forever. This cell was the ancestor of all animals on earth from the biggest blue whale to the smallest amoeba- and somewhere in between, you. This was so important because when those two cells merged they became more powerful and could produce more ATP. It became a powerhouse called mitochondria.
The host cell ensured its survival and gave the mitochondria the food. Mitochondria does a reverse photosynthesis, it takes sugar molecules and combusts them with oxygen to make ATP. It is the furnace inside the body which releases water, Carbon-di-oxide and heat. This opened up the way for creation of more complex cells. These cells started forming small communities which we call multi cellular life. Today you are a combination of trillions of such cells which are producing energy for you to stay alive. And we hardly give credit to them for our staying alive. The day this process of energy production is interrupted or stops – you die.
Every day you body is busy producing 90 million billion billion molecules of APT and it’s about your body weight. So now you understand that you need to make a whole persons equivalent of ATP to survive a day. You can’t store enough ATP in your body to last a few moments. It is constantly produced and constantly used up.
So, all the hard work is done by those tiny cells inside your body round the clock so that you can enjoy all the life’s pleasures at your will.
Thank you Telesfor sir.