by David Hobby, Arlington, Texas

--Editor's Note: David is a biology teacher who went on our Canyonlands trip in 2006 with us.

Have you ever wondered how our bodies make the energy for us to walk, talk, breathe, think, and for our hearts to beat twenty-four hours a day? The secret is found inside most of the body's cells where there is an organelle, far too small to be seen with the human eye, called the mitochondrion (pl., mitochondria). Cells usually have hundreds to thousands of mitochondria. Without them complex animals, such as humans, could not exist because our bodies would not produce enough energy.

One of the major functions of the mitochondria is to convert organic materials into energy in the form of a complex chemical called adenosine triphosphate (ATP). ATP is produced in the mitochondria by the citric acid cycle (also know as the tricarboxylic acid cycle (TCA) or the Krebs cycle), and by Electron Transport Phosphorylation.

Shown below is a diagram of the citric acid, or Krebs cycle:

Reproduced from Wikipedia, the free encyclopedia web site (, which currently (as of Jan. 31, 2007) has a different diagram than this, but on the same Kreb [Citric Acid] Cycle).

As you look at this diagram, note how complicated it is. There are at least eight complex chemical reactions that take place. If anything goes wrong in any of the reactions, the whole cycle will stop. If the reactions do not take place in the correct sequence, ATP will stop being produced. The same is true of Electron Transport Phosphorylation.

This could not have been an accident. It did not just happen by chance. It is far too complex. At every step of the cycle there is evidence of design by God, the master designer.

1. The right chemicals must be present at the right place.

2. These chemicals must be able to react with the other chemicals present.

3. These reactions must produce the correct chemicals to continue the stages of chemical reactions.

Everything must work right, not only now, but also when humans and the mitochondria were first created. This whole process is so complex that no one fully understands it. The best we can do is look at what God has done with awe, and praise God for His wisdom when we see His designs in all living things.

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