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The Chiral Story

The theory of Evolution tells us that life evolved from simple molecules in some pre-biotic soup. Theoretically, the rain leached materials from the rocks and the soil. Somewhere these materials gathered in a pool, the pre-biotic soup, the basic molecules of life were concentrated, and the first living cell was formed. This scenario or one like it would have been necessary for life to have developed on Earth purely by chance.

In order for this theory to work, the right type of molecules would have to form. One of the types of molecules necessary for all life, including one-celled life, is amino-acids. Amino-acids are the building blocks of all protein and enzymes. Protein is used to form things like muscle tissue, organs, and memory molecules. Enzymes control the chemical processes that make life possible. Without amino-acids it is not possible for life, as we know it, to exist.

It is not only important that amino-acids are present in this pre-biotic soup, but the right type of amino-acids must be present. If all of the right type of amino-acids were not there then life could not form.

There are twenty basic types of amino-acids that are used in all life forms. For the sake of argument let’s assume that all twenty types were present. Conditions necessary for life to form have still not been satisfied.

Amino-acids possess an important quality that chemists refer to as chirality. What is chirality? To answer this question let’s look at an example. Our hands possess the same quality as the amino-acids, chirality.

For a moment, let’s examine our hands. Let’s put them together palm to palm with the fingers pointing the same way. Notice that what we see is what we would see if we placed one of our hands on the surface of a mirror. Our hands are the mirror image of each other. The first of two qualities that a molecule must have to be considered chiral is that it must have a mirror image. That is, it must be possible to make another molecule that is the mirror image of the molecule of interest.

A lot of molecules can fit this description, but very few of them are chiral. There is a second quality that must be present. The molecules must not be super-imposable.

Let’s look at our hands again. With our fingers pointing the same direction, let’s place one of our hands on top of the other, palm to back of the hand. Notice that our right and left hands are oppositely arranged. Our thumbs do not line up and neither do the arrangement of our fingers line up. Our hands cannot be super-imposed on each other. This quality must be present in molecules in order for them to be considered chiral, or have “handedness.”

So then, in order for a molecule to be chiral, there must be another molecule that is its mirror image but is not super-imposable.

Ok, so what? We have defined what makes a molecule chiral, but how does this address the question of how life got started? First, as we mentioned earlier, the amino-acids that are so very important to life are chiral. That is, they possess handedness. There are left and right handed versions of nineteen of the twenty basic amino-acids. However, all nineteen of the chiral basic amino-acids in life are “left handed.” Not one of them is right handed. The right handed version of each of these molecules is not utilized in living organisms.

Why is this significant? Is there a problem in isolating just left handed molecules for life to form out of? Could not a pool of just left handed amino-acids have existed?

To answer this question, a chemist might go to the lab and try to make only left handed amino-acids. If he can make only left handed amino-acids then perhaps it could have happened by chance.

The chemist must simulate, as best as possible, the conditions that would have existed when these amino-acids were to have been produced. The starting materials from which the amino-acids are to be made must be the same. These starting materials do not possess the quality of handedness or chirality. This quality poses a problem for the chemist.

In order for the chemist to produce only left handed versions of the molecules, there must be some way to select a pathway that will produce only the desired molecule. That is, there must be a method that can be used that will produce only left handed molecules.

Molecules that are chiral, or have handedness, have certain properties that determine whether or not such a path exists. First, as we have noted, the right and left handed version of the molecules are identical except that they are the mirror images of each other and not super-imposable on each other. So they are made out of the same materials. Both of our hands are made alike, that is each has a thumb and four fingers. Each is attached to the wrist, and so forth.

If both the left and right handed amino-acids are made of the same materials, then the chemist cannot make only the left handed version by selecting different materials. The chemist must find a pathway that is different for left and right handed amino-acids. He needs an approach to building them that gives only left handed molecules.

However, chiral molecules, molecules with handedness, are chemically and energetically the same. They are only different in the three dimensional arrangement of their parts. Just as our hands are functionally the same except that they are non-super-imposable mirror images of each other.

This means that there is no pathway available for the chemist to make only left handed versions of the molecules if he starts from materials that do not have handedness. However, he must use materials that do not have handedness. When the chemist makes the amino-acids he discovers that he has made equal amounts of both the left and right handed versions. It is not possible to make only left handed amino-acids from materials that are not chiral.

This presents a major problem for the formation of life by chance. If it is not possible to make only left handed versions of the molecules, then there will be no pool of pure left handed amino-acids for life to form out of. Life is made up of left handed amino-acids. There are no right-handed amino-acids utilized in life. If it is not possible to have a pure pool of left handed amino-acids to work with then life could never have begun on Earth by chance.

This alone is enough to show that life didn’t evolve from non-life. If not accompanied by any other evidence the conclusion is obvious. Life was designed by a Designer. This Designer had to have been someone capable of separating the left and right handed versions of the basic amino-acids necessary for life. No human being possesses this ability, only someone with supernatural skills could have done it, and that someone is God.

This isn’t the end of the story, however. Other major hurdles exist for the formation of a living cell in a pre-biotic soup. The chemist is also faced with these hurdles.

The next hurdle is a chemical pathway hurdle. When starting materials are put together to form some new molecule, there are competing reactions that must be managed. In the case of building proteins and enzymes, which are made up of amino-acids, the difficulty is a competing reaction known as acid-base chemistry.

Acid-base chemistry is the fastest type of reaction in the “soup.” What the chemist wants to do, and what must happen by chance, is combine the amino-acids into a long chain. The amine (from which the term amino comes) must combine with the carboxylic acid (from which the term acid comes) to form a bond referred to as an amide or peptide bond. All names aside, one end of one amino-acid must join the other end of another amino-acid so that the two molecules become one longer molecule. The amine is a base and the carboxylic acid is an acid. The first reaction that will always take place is the acid-base reaction which renders the amine and the carboxylic acid useless. In other words, if the acid-base chemistry happens first the desired linking of the two amino-acids will not take place.

The acid-base chemistry will always happen first. Therefore, the chemist must perform another reaction to prevent the acid-base chemistry from taking place. The chemist must utilize a protecting group. He must protect the acid by converting it into something else with which the amine can react with to produce the desired link.

This complicates the process. Just having a pre-biotic soup with all the necessary ingredients in it is insufficient to build life. It takes a chemist many steps of careful work to make a link between two amino-acids. The amino-acids are not going to join together by chance. The acid-base chemistry will take place immediately and the amino-acids will stay separate amino-acids forever. No links will be formed and no life will develop.

The difficulty of life forming by chance in a pre-biotic soup from just the two issues discussed so far are enough to conclude that life did not happen by chance. It’s not the end of the story though. The basic enzymes needed for a single-celled life form to develop have been estimated to be at least two hundred different enzymes.

Enzymes are very long chains of amino-acids. They vary in length from just over a hundred to over a thousand amino-acids. Today, chemical specialists called peptide chemists make amino-acid chains in specially designed chemical equipment for medical research.

This specialized equipment is able to put together peptides (amino-acid chains) of up to twenty amino-acids long. Chains longer than twenty links are not attempted as it becomes nearly impossible to insure that the product obtained has the right sequence of amino-acids when the chain gets any longer.

If chemists with very specialized equipment and well developed methods cannot successfully produce amino-acid chains longer than twenty units, how are enzymes necessary for life going to be produced by chance. Chemists can’t even produce them in a laboratory with special equipment and well developed methods.

It’s far worse than just trying to get one enzyme, say a little over a hundred links long, to form by chance. This pre-biotic soup must produce the correct sequence of amino-acids in enzymes up to a thousand or more links in size. It must also, produce all two hundred of the needed varieties of enzymes required by the simplest of living cells.

It has been said that the chance of producing one enzyme of a hundred links or more in size, correctly by chance, is less likely than finding a single special grain of sand in the Sahara Desert. That’s just one small enzyme. What about the longer enzymes and what about all two hundred needed for the simplest of living cells?

So the story looks pretty grim for life forming by chance over any period of time. There is the problem of the amino-acids being all left handed. This cannot occur by chance. Acid-base chemistry gets in the way of producing the needed link between two amino-acids. Forming this link by chance is, also, not going to happen. Then the length of the chains and the number of different enzymes that are needed to be produced make it impossible for life to form by chance. However, even if all this was possible, life could still not occur by chance.

Having the needed enzymes is but one step. There is also DNA and RNA as well as the cell wall.

DNA and RNA are also chiral molecules, or molecules that have handedness. They also are very long chains. DNA and RNA are made up of chiral sugars known as ribose and deoxy-ribose. The problems in making only left handed amino-acids are present here as well.

DNA and RNA also require other materials for their formation known as nucleic acids. All of these DNA and RNA building blocks present significant problems in construction. The sugars and nucleic acids are not going to form by chance any more than pure left handed amino-acids are going to form by chance.

DNA and RNA are also very long chains like the enzymes and present another great difficulty in getting the sequences correct. These long chains are not going to be built correctly by chance. Even a chemist with modern methods and equipment is faced with an incredible challenge.

All of these materials, the amino-acids, ribose, deoxy-ribose, nucleic acids, must be present in the pre-biotic soup if life is to form by chance. The sugars, ribose and deoxy-ribose, require an oxidative environment to develop and the amino-acids require a reducing environment to develop. These two types of environments cannot both exist at the same time. The situation will either be reducing or oxidative, not both. So if conditions are right for the amino-acids to form they are wrong for the sugars to form and vice versa. Once again, life could not have formed by chance.

There is much more to the story than has been covered. A dozen articles this size could be written and still not cover all the problems associated with forming life from non-life. Clearly, life did not form by chance. Life had to have been designed.

The Designer of life had to have had incredible sophistication, a massive amount of knowledge, and total control over the chemistry. The obvious answer is that God is the Designer. God not only created all life and the universe, but wrote a Record for our reading through the hands of His servants. This Record is the Holy Bible.

In Genesis 1:1 we read, “In the beginning God, created the heaven and the earth.”

“All things were made by Him (Jesus Christ), and without Him was not anything made that was made.” John 1:3