In the Beginning - Biblical Creation and Science
By Nathan Aviezer
Professor of Physics Bar-Ilan University,
PO Box 90000, Ramat-Gan, 52900, Israel
KTAV Publishing House, Inc. Hoboken NJ 07030
IN THE BEGINNING
The Origin of Life
NUCLEIC ACIDS AND PROTEINS
The basic unit of all living organisms is the cell. The most important molecules in the living cell are the proteins and the nucleic acids.7 For our discussion of the origin of life, it is necessary to describe very briefly some of the basic properties of these two types of molecules.
One of the characteristic features of a living organism is its ability to reproduce itself. Living creatures reproduce, whereas inanimate objects do not.8 The reproduction of the organism depends, ultimately, on the reproduction of the individual cell. This is called cellular replication. The mechanism for cellular replication is identical in all living organisms. It is based on the unique properties of the nucleic acids known as DNA and RNA. (The older scientific literature spoke of chromosomes, which are now known to be extremely long strands of the nucleic acid DNA; a gene is a segment of a chromosome.)
A molecule of nucleic acid replicates by producing two identical daughter molecules from the original parent molecule. Furthermore, nucleic acids control the production of all the proteins in the cell. In this way, nucleic acids cause the cell to replicate. The complex processes that take place during cellular replication are now well understood.
A major component of the living cell is a group of large molecules called proteins. They make up about 70-80 percent of the dry weight of a typical cell. A living cell contains hundreds of different types of proteins, with each type carrying out a specialized task needed for the cell to function as a living entity. The proteins catalyze the chemical reactions that take place in the cell, control cellular metabolism, and "manufacture" many cellular "products." In brief, they regulate and control almost every activity that occurs in the cell. It would be quite impossible for any living cell to exist without proteins.
Where do proteins come from? All proteins are produced by the nucleic acids. No other mechanism exists for producing proteins. This assertion is known as the "central dogma of molecular biology."
What regulates the replication of nucleic acids? The replication of nucleic acids can take place only in the presence of certain proteins called enzymes. Indeed, without enzymes, nucleic acids could not exist at all. The large nucleic-acid molecules would decompose in the water of the cell (all living cells contain water) were it not for the stabilizing effect of the proteins.
IN THE BEGINNING
The discussion in the previous section provides the necessary background for a critical analysis of the proposal that life generated itself from inanimate matter.
There are four points to the argument.
1. All living cells require nucleic acids for replication.
Therefore, without nucleic acids, there can be no life.
2. All living cells require proteins to carry out the many activities needed to maintain the cell.
Therefore, without proteins, there can be no life.
3. Proteins are produced only by nucleic acids.
Therefore, without nucleic acids, there can be no proteins.
4. Nucleic acids are able to replicate only in the presence of proteins.
Therefore, without proteins, there can be no nucleic acids.
The paradox regarding the spontaneous origin of life can now be easily stated.
Points (I) and (2) imply that living cells need both proteins and nucleic acids.
Points (3) and (4) imply that neither of these complex molecules can be produced without the other.
Therefore, it follows that life could not have developed from inanimate matter because inanimate matter contains neither proteins nor nucleic acids.
This paradox is well known to biologists, who often compare it to the riddle of "which came first, the chicken or the egg?"
The analogy is clear. A few quotations will illustrate the point.
Nucleic acids could not replicate or direct protein synthesis without the help of preformed proteins; no proteins could be synthesized without the information stored in preformed nucleic acids. One of our major problems is to see how such a "hen-and egg" situation could have developed.9
(L.E. Orgel, The Origins of Life London: Chapman & Hall, 1973, p.49)
This, then, is still a point of debate among origin-of-life theorists: which came first, not the chicken or the egg, but nucleic acids or proteins? Right now, no one really knows.10
(F.H.Shu, The Physical Universe Mill Valley, CA.: University Science Books, 1982, p.533)
One of the many critical unresolved problems in understanding the origin of life is the first functional relation between proteins and nucleic acids - did proteins or nucleic acids occur first? 11
(D.G. Smith, chief ed., The Cambridge Encyclopedia of Earth Sciences Cambridge: At the University Press, 1981, p. 352)
This final state [in the origin of life] still remains totally incomprehensible, which explains why it has become the focus of intensive laboratory research.12
(J. Audouze et al., eds., The Cambridge Atlas of Astronomy Cambridge: At the University Press, 1985, p.389)
Nucleic acids cannot replicate without enzymes [proteins], and enzymes cannot be made without nucleic acids.13 (R.E. Dickerson, Scientific American, vol.239, Sept.1978, p. 65)
In view of the preceding discussion, it is quite clear that there exists no accepted scientific explanation for the origin of life from inanimate matter.