The cell is the basic living building block of all plants and animals on earth. Each cell is so tiny you can not see them without the aid of a microscope, yet so complex that scientists cannot fully understand how it carries out the tasks needed to make things live. Each cell can be compared to a walled city with factories to make proteins, enzymes and hormones. It has its own government to direct the cell’s activities. It has a police force to stand guard and control what goes in and out of the cell through the cell membrane. It has its own streets or transportation system to transport materials in and around the cell.

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Under the direction of the cell’s “city hall” or nucleus, these macro-molecular machines assemble the 20 different kinds of amino acids in the cells to form the proteins . Proteins then help the cell to grow or are used to control chemical reactions that make everything happen in the cell. Two thousand proteins serving as enzymes are needed for the cells’ activities.Even the simplest life forms whose whole bodies consist of only a single cell are a marvel of compact intricacy. Bacteria cells are so tiny that 500 of them could fit on the period at the end of this sentence. Yet according to the book: “The New Biology” page 30 - “The average cell caries out hundreds of chemical reactions every second and can reproduce itself every twenty minutes or so. Biologist Francois Jacob informs us that the bacterial cell ‘carries out some 2,000 distinct reactions with incomparable skill, in the smallest space imaginable. These two thousand reactions diverge and converge at top speed, without ever becoming tangled’.
Though these cells can weigh as little as 1/1,000,000,000,000th of a gram “each is in effect a veritable micro-miniaturized factory containing thousands of exquisitely designed pieces of intricate molecular machinery, made up altogether of one thousand million atoms, far more complicated than any machine built by man and absolutely without parallel in the non-living world.” (microbiologist Michael Denton)

One science writer observed: "The normal growth of even the simplest living cell requires that tens of thousands of chemical reactions occur in coordinated fashion...How within one tiny cell can 20,000 reactions be controlled at once?" "The New York Times" of February 15, 2000 noted: "The average human cell is too small to be seen, yet at any moment up to 30,000 of its 100,000 genes may be flickering on or off, executing the cell's housekeeping needs or responding to messages from other cells." Nature" magazine in an article entitled "Engines of Creation" reported on the discovery of tiny motors within each cell of the body which rotate to create adenosine triphosphate, the power source of cells.