Chemistry of life

 

Chemical reactions.

In the past I’ve been hesitant to explain exactly how simple it is to understand that life is a bunch of chemical reactions. I didn’t want to talk down to my readers. This morning I received an e-mail that asked ‘what chemical reaction’ started life on this planet. So, for anyone who already understands that every thought we think, every emotion we feel, every single thing that life involves is the direct result of specific chemical reactions, you don’t need to read any further.

For those who don’t understand what chemistry has to do with life, read on, I’ll make it simple.

A chemical reaction is when electrons in an atom’s shell are ‘excited.’ Electrons break and form bonds that create different molecules. Whether you are mixing vinegar and baking soda or memorizing a phone number, a chemical reaction is taking place.

When brain imaging shows a particular part of the brain with high activity, it is showing intense chemical activity. Electrons in motion is probably a reasonable way to understand chemical reactions, and therefore, brain activity. One brain cell whose electrons are excited transfers the energy by some chemical reaction to other brain cells. These ‘thoughts’ show on brain scans.

When I was in college botany classes, I was taught that photosynthesis was so complex and wondrous that scientists still didn’t understand it. Let me explain it to you.

Sunlight hits the carbon dioxide and water in the plant cell, electrons are transferred, and sugar results. The sugar goes through one of various other chemical reactions with other molecules and changes into starch or protein or some other organic molecule.

Unlike plants, animals can’t convert sunlight into chemical energy so we get it from plants or other animals that have already eaten the plant. Our muscles and blood, brains and skin, all are made up of the basic carbon molecules (combined with other chemicals the plant gets from the ground or air) that began as simple sugars made from photosynthesis.

But 3.5 billion years ago what chemical reaction could possibly have started life on earth? Scientists have speculated on the probable mix of chemicals on earth at that time, but whether the chemical reaction started with lightening, heat or motion, we don’t know. We do know that in some form, the energy of the sun put electrons in motion and the first organic molecules began the long and varied process of evolution.

That chemical reaction might have happened a million times or once, but we know that all life on earth today is a result of just one of those reactions. The single reaction that out performed the others started the long chain of adaptation (evolution) that eventually resulted in plants and animals. From the things you feel and think to the way your cells process energy, sight, hearing, touch, these are all chemical reactions.

Nancy Sherer

 

 


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