The Cell

An adult is composed of some 100 trillion cells, each of which is incomprehensibly complex. To illustrate the complexity, Newsweek magazine compared a cell to a walled city. “Power plants generate the cell’s energy,” the magazine said. “Factories produce proteins, vital units of chemical commerce. Complex transportation systems guide specific chemicals from point to point within the cell and beyond. Sentries at the barricades control the export and import markets, and monitor the outside world for signs of danger. Disciplined biological armies stand ready to grapple with invaders. A centralized genetic government maintains order.”

Consider how you​—some 100 trillion cells of you—​came about. You began as a single cell that was formed when the sperm from your father united with an egg cell from your mother. At that uniting, the plans were drawn up within the DNA (short for deoxyribonucleic acid) of that newly formed cell to produce what eventually became you​—an entirely new and unique human. The instructions within the DNA “if written out,” it is said, “would fill a thousand 600-​page books.”

In time, that original cell began dividing, making two cells, then four, eight, and so on. Finally, after about 270 days​—during which time thousands of millions of cells of many different kinds had developed within your mother to form a baby—​YOU were born. It is as if that first cell had a huge room full of books with detailed instructions on how to make you. But just as wonderful is the fact that these complicated instructions were passed along to every succeeding cell. Yes, amazingly, each of the cells in your body has all the same information as the original fertilized egg contained!

Consider this also. Since each cell has the information to produce all kinds of cells, when it came time, say, to make heart cells, how were the instructions to make all the other cells suppressed? Seemingly, acting like a contractor with a complete cabinet of blueprints for making a baby, a cell picked from its file cabinet a blueprint for making heart cells. Another cell picked out a different blueprint with instructions for producing nerve cells, yet another took a blueprint for making liver cells, and so on. Surely, this still unexplained ability of a cell to select the instructions needed to produce a particular kind of cell and at the same time suppress all other instructions is another of the many “miracles that take us from conception to birth.”

Yet, there is much more to it. For example, the cells of the heart need to be stimulated so that they contract rhythmically. Thus, within the heart a complex system was constructed for generating electrical impulses to cause the heart to beat at a proper rate to sustain the body in the activity in which it is engaged. Truly, a miracle of design! No wonder doctors have said of the heart: “It is more efficient than any machine of any kind yet devised by man.”

The Cell​—A Miracle of Design

Cell Membrane

The covering that controls what enters and leaves the cell

Nucleus

Enclosed in a double-​membrane envelope, it is the control center that directs the cell’s activities

Ribosomes

Structures on which amino acids are assembled into proteins

Chromosomes

They contain the cell’s DNA, its genetic master plan

Nucleolus

The site where ribosomes are assembled

Endoplasmic Reticulum

Sheets of membranes that store or transport the proteins made by the ribosomes attached to them (some ribosomes float free in the cell)

Mitochondria

Production centers for ATP, the molecules that supply energy for the cell

Golgi Body

A group of flattened membrane sacs that package and distribute proteins made by the cell

Centrioles

They lie near the nucleus and are important in cell reproduction