THE INTRICATE MACHINERY OF A LIVING CELL

Once thought to be a simple bag of chemicals, the cell is now understood to be an elaborate system of molecular machinery that surpasses a modern city in complexity.

In Darwin’s time living cells were regarded as simple bags of chemicals that could have arisen spontaneously from organic compounds. However, it is now clear that cells contain intricate biochemical machinery. The steps by which this machinery may have originated are unknown and difficult to imagine. Thus it is no longer justifiable to simply take it for granted that living cells have evolved from chemicals by physical processes. Some important structures of typical plant and animal cells are depicted in this illustration.

(1) The ribosomes manufacture protein molecules by following blueprints encoded in messenger RNA. Although they appear here as mere dots, the ribosomes have a complex structure.

(2) The endoplasmic, reticulum consists of a complex of membranes that form internal compartments used in the synthesis and transport of various compounds produced by the cell.

(3) The nucleus contains the hereditary material, DNA, which carries instructions for the operation and perpetuation of the cellular machinery. Complex molecular processes are involved in replicating the DNA.

(4) The nucleolus is a factory for the partial manufacture of ribosomes.

(5) The microtubules form a complex latticework that gives form to the cell and enables it to systematically move and change shape.

(6) Some cells possess cilia, whiplike structures that execute a swimming stroke through the action of an internal arrangement of sliding rods.

(7) Lysosomes contain enzymes that break down unwanted material within the cell.

(8) The chloroplasts, found in plant cells, are complex chemical factories that carry out photosynthesis—the storage of solar energy in the form of sugar molecules.

(9) The cellular membrane is equipped with many complex protein molecules that regulate the passage of molecules into and out of the cell and act as sensors informing the cell of external conditions.

(10) The mitochondria are chemical factories that generate energy for the cell through the controlled breakdown of food molecules.

COULD LIFE ARISE BY CHANCE?

To give some idea of what exactly is involved in supposing that life could have emerged by random combination of chemicals in a primordial soup, let us imagine that this soup covered the entire surface of the earth to a depth of one mile. We shall divide this volume into tiny cubes measuring one angstrom unit on each side. (An angstrom unit is about the size of a single hydrogen atom.) Let’s also assume that the soup is extremely concentrated, so that reactions are taking place within each of the cubes within the soup.

Now, in the expectation of obtaining the simplest possible self-reproducing organism, let the reactions take place a billion times per second in each cube. And let’s further assume that the reactions have been going on for 4.5 billion years, the estimated age of the earth.

As we have seen in the accompanying article, scientists Fred Hoyle and Chandra Wickramasinghe have estimated that the chance of obtaining the simplest self-reproducing system by random combination of molecules is at best somewhere in the neighborhood of 1 in 10 to the power of 40,000 attempts. But if out of extreme generosity we reduce the required number of proteins from 2,000 to only 100, then the probability is still 1 in 10 to the power of 2,000.

Now, if you add up all the possible attempted billion-per-second combinations in our hypothetical primordial soup, you wind up with only 10 to the power of 74 throws of the chemical dice. That means the odds of getting the required self-reproducing system out of our soup would be 1 in 10 to the power of 1,926. We wouldn’t expect that to happen in the entire course of the earth’s history!

Of course, a diehard gambler might say it’s highly unlikely but it just could happen by chance. But this is a completely meaningless use of the word chance. In order for a statement about an event with a nonzero probability of happening to be meaningful, we would have to observe enough repetitions of the event to establish a statistical pattern. Only this would allow us to say, “This event has probability p of happening.”
For example, we say that when we toss a coin there is one chance in two that it will turn up heads. This probability is established by examining the behavior of the coin over several hundred trials. Now, if you have an event with a probability of one in a million, it would take hundreds of millions of trials to establish this. And if the event has an estimated probability of 1 in 10 to the power of 2000, you would need many times that number of trials. The basic point is this: What is meant by a probability of 1 out of 10 to the power of 2000 is that a certain statistical pattern corresponding to this figure will be observed over the required vast number of trials. If there is no possibility of performing these trials (as is certainly the case here), then there is no meaning to saying an event happens with that very small probability.

On this planet, as we have seen, you can only have a maximum of 10 to the power of 74 trials. Now, we can be extremely generous and grant the chemical evolutionists that the trials can be taking place in primordial soups on as many planets as there are atoms in the entire universe—about 10 to the power of 80 . Then you get a grand total of 10 to the power of 154 trials—still an infinitesimal number compared to 10 to the power of 2000. The conclusion is simple. It’s meaningless to talk about the origin of life in terms of chance. To say it happened by chance is just the same as saying it happened, and we already know that. In that case, all we can say is that life is a unique event.