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The World's Tiniest Motors

By Joseph Pride and the Answers in Genesis staff
Printed in Practical Homeschooling #40, 2001.

Motors the size of molecules show why the "simple" cell is irreducibly complex
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Joseph Pride

How many students are truly familiar with the simple cell? Draw a picture of a paramecium. Every elementary-aged kid can point out its three main parts: the membrane, the goo, and the nucleus. But did you know the "simple" cell isn't really simple at all? In fact, the world's top scientists are still struggling to figure it out!

For life to exist, assuming that the process of creative evolution works, it must be possible to create a single cell randomly by natural processes. This single cell must be capable of surviving, as well as reproducing before something kills it. That's why the "simple cell" is a major premise of evolution.

However, the odds of spontaneous generation are considered incredibly small. A cell so simple it could only survive by being treated like a pet would require 256 kinds of proteins. It would have practically no genetic adaptability and would be unable to digest complex compounds.1 Yet according to information science, given favorable conditions, a billion years could only produce a single small polypeptide 49 amino acid residues long, about an eighth the size of a single protein.2 This assumes, of course, that many chemical hurdles can be overcome, which is far from likely.3 And even if the proteins existed, of course, the odds against them naturally organizing into anything useful are monumental.

Why is so much data necessary for a cell? Cells are full of moving parts. A typical animal cell will have mitochondria, at least one Golgi complex, smooth endoplasmic reticulum, a rough endoplasmic reticulum covered in ribosomes generating RNA, a nucleus, centrioles, microtubules disassembled and reassembled where needed throughout the cell, a system of reproduction and "dividing" still not understood, vacuoles, thousands of RNA "instructions," and motor proteins such as kinesin to carry pieces where needed. There are other organelles, and scientists are still studying the ones named here, though their functions are known, to find out exactly how they work. Rather than a "simple machine," a cell could be seen as an entire city full of machines. Since PHS is a magazine and smaller than an encyclopedia, we'll focus on the capabilities of just a few of these machines.

Irreducible Complexity

In 1996, Dr. Michael J. Behe, a professor of biochemistry at Lehigh University (and an evolutionist), published a book challenging classical Darwinian evolution entitled Darwin's Black Box. In this book he uses the flagellum to introduce the concept of "irreducible complexity." If a structure is so complex that all of its parts must initially be present in a suitably functioning manner, it is said to be irreducibly complex. And all the parts of a bacterial flagellum must have been present from the start in order to function at all.

Let's use an ordinary automobile's alternator for an example. This machine has a simple function: when you rotate it, it produces alternating current. Let's say a lab comes up with a hundred new designs for alternators. The buyer will naturally want the one which produces the strongest current for the least energy input. All the others will go out of production. This is akin to the theory of random mutation and natural selection. Assuming that you have a mechanism for making a hundred truly random changes, and that the buyer is smart enough to always choose the best, not the almost-best, this is fine, as long as you have an alternator to start with. But if you don't have an alternator to start with, a hundred random changes to a pile of parts won't produce a machine that even poorly fulfills an alternator's function. Even given that one of those changes could produce a magnetic coil, that coil is still worth nothing by itself as an alternator. You need the whole machine or you're no better off than if you had nothing.

Likewise, even if you could randomly produce a backboard for a mousetrap, you'd still be several parts short of a mousetrap and the board would be no more useful than when you started. So there would be no reason for natural selection to favor your board any more than it would favor the materials from which the board was made.

The same principle applies to the theory of evolution in animals and the simple cell. Any device which is made of different parts, none of which do their job without the others, is irreducibly complex. Therefore, the "creator" of evolution, natural selection coupled with mutation, wouldn't help at all.

Now let's look at two irreducibly complex pieces of a "simple" cell.


The flagellum is a corkscrew-shaped, hair-like appendage attached to the cell surface, which acts like a propeller, allowing a bacterium to swim. The most interesting aspect of the flagellum is that it is attached to - and rotated by - a tiny, electrical motor made of different kinds of protein.

Like an electrical motor, the flagellum contains a rod (drive shaft), a hook (universal joint), L and P rings (bushings/bearings), S and M rings (rotor), and a C ring and stud (stator). The flagellar filament (propeller) is attached to the flagellar motor via the hook. To function completely, the flagellum requires over 40 different proteins. The electrical power for driving the motor is supplied by the voltage difference developed across the cell (plasma) membrane.

This combined machine is obviously irreducibly complex. How a flagellum is used, however, adds an additional level of complexity to the picture.

Some bacteria have a single flagellum located at the end of a rod-shaped cell. To move in an opposite direction, a bacterium simply changes the direction of rotation of the flagellum. Other bacteria have a flagellum at both ends of the cell and use one flagellum for going in one direction and the other for going in the opposite direction. A third group of bacteria has many flagella surrounding the cell. These flagella wrap themselves together in a helical bundle at one end of the cell and rotate in unison to move the cell in one direction. If the cell wants to change direction, the flagella unwrap themselves, move to the opposite end of the cell, reform the bundle, and again rotate in a coordinated fashion.

The structural complexity and finely tuned coordination of the bacterial flagellum certainly suggests it was created by a skilled engineer with an attention to detail, not thrown together by a random breeze.

The F1-ATPase Motor

Doctors and computer scientists would love to be able to work with machines close to the size of the one described above. The number of parts in a motor make it quite difficult to make that motor anywhere near as small as a flagellum. Ingenious scientists are all the time coming up with better ways to build micromotors,4 but they're still not even close.5

But while scientists are busy trying to catch up with the flagellum, there are motors far smaller! Living cells have many complex molecules which serve as mini-machines and chemical factories - enzymes. An enzyme is a big and complex molecule, but a molecule nonetheless. Some enzymes act as catalysts, "grabbing" separate molecules and pulling them together to bond, then releasing the resulting molecule, thus speeding up chemical reactions. One enzyme6 has been shown to spin "like a motor" to produce ATP, adenosine tri-phosphate, the "energy currency" of life.7 This molecule motor, which has nine protein components, is so tiny that 100,000 million million would fill the volume of a pinhead.8 This motor produces an immense torque (turning force) for its size. It rotates a strand of another protein9 100 times its own length. Also, when driving a heavy load, it probably changes to a lower gear, as any well-designed motor should.


The famous British evolutionist (and communist) J.B.S. Haldane claimed in 1949 that evolution could never produce "various mechanisms, such as the wheel and magnet, which would be useless till fairly perfect."10 Therefore such machines in organisms would, in his opinion, prove evolution false. These molecular motors have indeed fulfilled one of Haldane's criteria. Also, turtles11 and monarch butterflies12 which use magnetic sensors for navigation fulfill Haldane's other criterion.

The theory of evolution tends to change, to account for difficulties presented to it by science. But the simple cell isn't just difficult for evolution to explain. It's impossible.

To a scientist, the simple cell is a treasure trove full of technology we can only hope to understand, reproduce, and use. To a creationist, the simple cell is also a testament to the ingenuity, power, and fine detail of which God is capable. To an evolutionist, a simple cell is a huge question mark which asks "How on the face of this earth?" Without a designer and a creator, there is no way for a simple cell to exist.


  1. W. Wells, "Taking life to bits," New Scientist, 155(2095):30-33, 1997.

  2. H.P. Yockey, A Calculation of the Probability of Spontaneous Biogenesis by Information Theory, J. Theor. Biol., 67:377-398, 1977.

  3. C.B. Thaxton, W.L. Bradley & R.L. Olsen, The Mystery of Life's Origin, Philosophical Library Inc., New York, 1984; W.R. Bird, W.R., 1991; The Origin of Species: Revisited, Thomas Nelson, Inc., Nashville, Tennessee, Vol. I Part III, 1991; S.E. Aw, "The Origin of Life: A Critique of Current Scientific Models" Creation Ex Nihilo Technical Journal, 10(3):300-314, 1996; J.D. Sarfati, 1997 "Self- Replicating Enzymes?" Creation Ex Nihilo Technical Journal 11(1):4-6, 1997

  4. "Invasion of the micromachines," New Scientist 150(2036):28-33, 29 June 1996.

  5. The motor driving a flagellum measures about 40 nm across and 60 nm high (1 nm = 10-9 m) and spins over 1,000 times per second.

  6. The F1-ATPase motor is a flattened sphere about 10 nm across by 8 nm high.

  7. ATP stands for adenosine triphosphate. It is a high-energy compound, and releases this energy by losing a phosphate group and leaving ADP, adenosine diphosphate.

  8. The F1-ATPase motor, shaped like a flattened sphere, measures about 10 nm across by 8 nm high.

  9. The filament is a protein called actin.

  10. Dewar, D., Davies, L.M. and Haldane, J.B.S., 1949. Is Evolution a Myth? A Debate between D. Dewar and L.M. Davies vs. J.B.S. Haldane, Watts & Co. Ltd/Paternoster Press, London, p. 90.

  11. Sarfati, J.D., 1997. His article points out that turtles can read magnetic maps.

  12. Poirier, J.H., 1997. "The Magnificent Migrating Monarch." Creation Ex Nihilo 20(1):28-31. But monarchs only use the earth's magnetic field to give them the general direction, while they rely on the sun's position for most of their navigation.
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