Tuesday, August 17, 2010

Problem Solving Cells

Garden hoses have an innate tendency to weave themselves into bewildering, inextricable tangles. Perhaps this is just another manifestation of Murphy’s law. Our body cells solve far more intricate problems than are posed by the most complex garden hose project imaginable. Living cells possess coded information and have the ability to issue instructions, synthesize countless new products, and regulate numerous activities. The cell’s activities have the unmistakable signature of a mind in its design and function.

What problems, we may ask, does the tiny cell solve? For starters, consider that in each body cell the DNA double helix molecules, tightly packed in loops and folds inside the cell’s nucleus, would be six feet long if stretched out. DNA molecules are composed of two delicately twisted ribbons of sugar-phosphate backbones. Between these backbones, billions of chemical “base pairs” are positioned like rungs on a ladder. Molecular biologists call these base pairs “CG” and “AT,” shorthand for their chemical composition.

The base-paired spiral, if stretched out, could be visualized as a single strand of material, like a string. But the strand does not remain straight like a garden hose leading to a distant corner of our lawn. Imagine that we wrapped our hose two or three times around a thick spindle every few feet. The analogy to DNA is strong. At frequent intervals the DNA strand is wound around eight-molecule protein packages. These structures are then called nucleosomes. Another analogy is winding yarn on a spool. Some writers report the product of this periodic winding of the strand around the protein packages appears similar to “beads on a string.”

Most remarkable, the DNA strands must be unraveled and reassembled many times during the process of DNA replication, RNA synthesis, and other cell activities. One article reported “No one knows exactly how cells solve this topological nightmare.” That secret, however, abides with the cell’s Master Designer. It appears the cell solves the problem of keeping its DNA in order far more effectively than most people deal with tangles in garden hoses and balls of yarn.

My brief review does not do justice to the grandeur of the process. The layperson is not obligated to know all the intricate details, but rare is the person who cannot express wonder and amazement over the cell and intuitively recognize that its design and achievement is the product of an intelligent mind.