As I promised (threatened?!) you in the last letter, I will briefly describe some of the biochemical terms that are crucial for an understanding of some aspects of the theory of evolution. This may be a tough section for you to plow through, but you should be able to do it and come to a richer appreciation of the world and nature in its complexity and at the same time, its simplicity.

The most crucial molecules for operations carried out in the body are called proteins. Proteins themselves consist of smaller constituent units called amino acids. Thus, proteins could be likened to a pearl necklace with the individual amino acids representing the actual beads of pearls. So where do these proteins come from? The raw material comes from the proteins which are consumed in our diet and broken up, in digestion, into the individual amino acids.

The interesting and crucial aspect of amino acids is that they can link at two different points and this is what allows them to form proteins. One end contains a nitrogen atom (the amino portion) whereas the other contains carbon and oxygen (the acid portion, and hence amino acid). It is absolutely necessary to have molecules with two points of possible links (bonds) or proteins would not be able to form. So the nitrogen end of one amino acid links up with the acid end of another and so it goes on and on. Thus, as an example, insulin is composed of 51 amino acids bonded together. The number of amino acids which can be used as the raw material in biological systems to generate proteins is quite limited; it is twenty. It is possible to synthesize other amino acids in the lab but these, for a variety of reasons, cannot be incorporated into biological systems.

We have briefly defined what amino acids are, what proteins are, but the question arises – how do these amino acids combine in the body to form the needed proteins. Remember also, the sequence, the order of amino acids is crucial if we are to have a functioning protein. This seems like a daunting problem and here is where the molecule DeoxyriboNucleic Acid (DNA) comes in. Now, if you were to look at DNA outside the cell it would look like a simple strand of nylon and would be totally inert – a useless molecule in every sense of the word. DNA on its own would serve no purpose. So it isn’t simply that DNA plays a crucial role, but DNA when it is placed into the environment of the cell that it takes on some amazing properties. Here it becomes the wonder molecule which directs the production of proteins through an ingenious but structurally uncomplicated process.

So let’s take a look at DNA. This is a molecule with repetitive units (polymer) of deoxyribose (a type of sugar), a phosphate unit (a cluster of phosphorus and oxygen atoms) and nitrogen bases (bases are molecules whose pH is above 7). It is the nitrogen bases that actually can vary and allow the DNA to produce different proteins. There are amazingly only four bases that are present in DNA: adenine, guanine, cytosine, and thymine and these are sometimes represented schematically by their first letters: A, G, C, and T respectively. From this we see how simple the DNA molecule is in terms of its chemical components but it is also a very elegant system for generating proteins which are so crucial for the body. And one of the important reasons for its simplicity is to minimize the chances of mistakes being made (mutations).

Before we go any further we need to define another crucial term – the gene. Genes are stretches of DNA which consist of specific sequences of nitrogen bases on the DNA and these sequences are coded for various amino acids. Three nitrogen bases in a row are used to code for different amino acids and these triplets are called codons. These codons are specific for the different amino acid and so, there is no danger of mixing the amino acids up. So you see, a specific sequence of bases will code for a specific sequence of amino acids which when linked together, form the protein needed by the body. These base sequences are called the genetic code. The code has a definite starting point on the DNA and has a terminating point so we get the proper sequence of amino acids with the proper length also. The sequence or order of amino acids in a protein is called its primary structure and it plays an extremely important role in the function of the protein – a wrong sequence gives a non-functioning protein. There are other factors which play a role in protein activity such as their 3-dimensional shapes (for example, a factor important in mad cow’s disease) but we do not need to consider them for the purposes of our discussion.

This is all very interesting and informative but what are some of the important points I am trying to bring out?

The first point is that the genetic code is universal. The three base code for each different amino acids is the same in all living creatures showing that the proposal that we all come from the same biological source and operate under the same biochemical laws has empirical backing. Notice as well, how simple the code is. It is the different bases that determine the building up of proteins – the deoxyribose and phosphate groups are there to hold the bases in the right geometry. So, for a system such as this to arise, through chemical or physical means, is not that far-fetched since it does not involve too many different fundamental components. It would seem that there are innumerable possibilities, as for example using different amino acids other than the 20 used in biological systems, but we soon come to see that the possibilities are quite limited. The other possible amino acids simply cannot function with DNA because of an incorrect geometry or shape. They simply do not line up correctly. The other interesting point that arises from the consideration of biochemistry is that the emergence of sentience – awareness – is inevitable and therefore God can achieve His goals without ‘direct’ intervention basing Himself on chemical and physical properties of matter. You see, we often denigrate matter without reflecting on what a mysterious and marvelous thing it is. We should not see the theory of evolution as somehow negating God’s participation in nature and the biosphere, as somehow showing that God is ‘unnecessary’. The world is not as chaotic as sometimes we think and the claims of chance being the supreme decider of what happens is really overstated.

I know that your head is probably spinning from all this talk about chemistry and molecules and bonds. I think we do need to understand at least a little about how our world functions so that we can better respond to challenges that are quickly thrown against our faith. But I think the time has come to change our path a little and what I want to do is discuss a certain species of spider. I know that you, like I, really dislike spiders but consider the following.

There is a species of spider which is really quite unique. She, like all spiders, has no stomach and we will see the relevance of this shortly. The other thing is that this spider does not leave her eggs to chance. She gathers the eggs onto her back making her look as if she were a grotesque hunchback. She of course looks after her young but this is not the unusualness about her that I want to talk about. Instead, I want to focus on her “last supper”. As sometimes happens in nature, food becomes scarce and the young spiders are threatened with death. But then she performs a ‘loving service’. She releases her digestive juices into her unprotected body and the juices start to dissolve her flesh making it available for ingestion by the baby spiders. She dies and becomes the flesh that feeds her young and saves them from death by famine. She herself becomes food.

And Jesus said to those standing around him: “I am the bread of life. I am the living bread that came down from heaven; if anyone eats of this bread, he will live forever.” Take and eat we are told every Sunday. And here, in the spider that we have been told to despise and hate, in this spider we see an echo of the ‘last supper’. We are called even here to see the sacrificial love that undergirds the whole universe.

This is my partial answer to those who see only meaningless suffering in nature which seems so pointless and wasteful. There is something else if only we have eyes to see. There are messages buried even in actions that are seemingly so insignificant that we can easily bypass them. We are instructed to see beyond our hates and beyond our prejudices to a deeper layer of reality that speaks so quietly but eloquently about God’s presence and His actions in creation. And we are instructed to look for God’s presence and actions even in the smallest of creatures.

The last thing I want to say is to respect everyone that we meet even if we may think them intellectually not at a level that we expect. That person standing before you is carrying out chemical reactions that if I were able to replicate in the lab, I would surely win a Nobel Prize. Everyone we meet is a potential “Nobel Prize Winner”, even those who seem mentally incapacitated. Something to keep in mind.

Sincerely,
Bar-Abbas