What do many scientists claim? All living cells fall into two major categories​—those with a nucleus and those without. Human, animal, and plant cells have a nucleus. Bacterial cells do not. Cells with a nucleus are called eukaryotic. Those without a nucleus are known as prokaryotic. Since prokaryotic cells are relatively less complex than eukaryotic cells, many believe that animal and plant cells must have evolved from bacterial cells.

In fact, many teach that for millions of years, some “simple” prokaryotic cells swallowed other cells but did not digest  them. Instead, the theory goes, unintelligent “nature” figured out a way not only to make radical changes in the function of the ingested cells but also to keep the adapted cells inside of the “host” cell when it replicated.⁹ a

What does the Bible say? The Bible states that life on earth is the product of an intelligent mind. Note the Bible’s clear logic: “Of course, every house is constructed by someone, but he that constructed all things is God.” (Hebrews 3:4) Another Bible passage says: “How many your works are, O Jehovah! All of them in wisdom you have made. The earth is full of your productions. . . . There are moving things without number, living creatures, small as well as great.”​—Psalm 104:24, 25.

What does the evidence reveal? Advances in microbiology have made it possible to peer into the awe-inspiring interior of the simplest living prokaryotic cells known. Evolutionary scientists theorize that the first living cells must have looked something like these cells.¹⁰

If the theory of evolution is true, it should offer a plausible explanation of how the first “simple” cell formed by chance. On the other hand, if life was created, there should be evidence of ingenious design even in the smallest of creatures. Why not take a tour of a prokaryotic cell? As you do so, ask yourself whether such a cell could arise by chance.

To tour a prokaryotic cell, you would have to shrink to a size that is hundreds of times smaller than the period at the end of this sentence. Keeping you out of the cell is a tough, flexible membrane that acts like a brick and mortar wall surrounding a factory. It would take some 10,000 layers of this membrane to equal the thickness of a sheet of paper. But the membrane of a cell is much more sophisticated than the brick wall. In what ways?

Like the wall surrounding a factory, the membrane of a cell shields the contents from a potentially hostile environment. However, the membrane is not solid; it allows the cell to “breathe,” permitting small molecules, such as oxygen, to pass in or out. But the membrane blocks more complex, potentially damaging molecules from entering without the cell’s permission. The membrane also prevents useful molecules from leaving the cell. How does the membrane manage such feats?

Think again of a factory. It might have security guards who monitor the products that enter and leave through the doorways in the factory wall. Similarly, the cell membrane has special protein molecules embedded in it that act like the doors and the security guards.

 Some of these proteins (1) have a hole through the middle of them that allows only specific types of molecules in and out of the cell. Other proteins are open on one side of the cell membrane (2) and closed on the other. They have a docking site (3) shaped to fit a specific substance. When that substance docks, the other end of the protein opens and releases the cargo through the membrane (4). All this activity is happening on the surface of even the simplest of cells.

Imagine that you have been allowed past the “security guard” and are now inside the cell. The interior of a prokaryotic cell is filled with a watery fluid that is rich in nutrients, salts, and other substances. The cell uses these raw ingredients to manufacture the products it needs. But the process is not haphazard. Like an efficiently run factory, the cell organizes thousands of chemical reactions so that they take place in a specific order and according to a set timetable.

A cell spends a lot of its time making proteins. How does it do so? First, you would see the cell make about 20 different basic building blocks called amino acids. These building blocks are delivered to the ribosomes (5), which may be likened to automated machines that link the amino acids in a precise order to form a specific protein. Just as the operations of a factory might be governed by a central computer program, many of the functions of a cell are governed by a “computer program,” or code, known as DNA (6). From the DNA, the ribosome receives a copy of detailed instructions that tell it which protein to build and how to build it (7).

What happens as the protein is made is nothing short of amazing! Each one folds into a unique three-dimensional shape (8). It is this shape that determines the specialized job that the protein will do. b Picture a production line where engine parts are being assembled. Each part needs to be precisely constructed if the  engine is to work. Similarly, if a protein is not precisely constructed and folded to exactly the right shape, it will not be able to do its work properly and may even damage the cell.

How does the protein find its way from where it was made to where it is needed? Each protein the cell makes has a built-in “address tag” that ensures that the protein will be delivered to where it is needed. Although thousands of proteins are built and delivered each minute, each one arrives at the correct destination.

Why do these facts matter? The complex molecules in the simplest living thing cannot reproduce alone. Outside the cell, they break down. Inside the cell, they cannot reproduce without the help of other complex molecules. For example, enzymes are needed to produce a special energy molecule called adenosine triphosphate (ATP), but energy from ATP is needed to produce enzymes. Similarly, DNA (section 3 discusses this molecule) is required to make enzymes, but enzymes are required to make DNA. Also, other proteins can be made only by  a cell, but a cell can be made only with proteins. c

Microbiologist Radu Popa does not agree with the Bible’s account of creation. Yet, in 2004 he asked: “How can nature make life if we failed with all the experimental conditions controlled?”¹³ He also stated: “The complexity of the mechanisms required for the functioning of a living cell is so large that a simultaneous emergence by chance seems impossible.”¹⁴

What do you think? The theory of evolution tries to account for the origin of life on earth without the necessity of divine intervention. However, the more that scientists discover about life, the less likely it appears that it could arise by chance. To sidestep this dilemma, some evolutionary scientists would like to make a distinction between the theory of evolution and the question of the origin of life. But does that sound reasonable to you?

The theory of evolution rests on the notion that a long series of fortunate accidents produced life to start with. It then proposes that another series of undirected accidents produced the astonishing diversity and complexity of all living things. However, if the foundation of the theory is missing, what happens to the other theories that are built on this assumption? Just as a skyscraper built without a foundation would collapse, a theory of evolution that cannot explain the origin of life will crumble.

After briefly considering the structure and function of a “simple” cell, what do you see​—evidence of many accidents or proof of brilliant design? If you are still unsure, take a closer look at the “master program” that controls the functions of all cells.