When a child receives a new toy, before asking “How does it work?” he may pause to admire its structure and other physical features. Likewise, before considering the function of the cells in our body--that is, what cells accomplish in their role as the fundamental units of life--we may pause to consider some of their basic structural characteristics.
The most well-known structure within the cell boundary (the plasma membrane) is the nucleus. Inside the nucleus, all the cell’s DNA molecules are packaged in fibers called chromatin which are wound together to improve packing efficiency. Chromatin fibers then loop repeatedly and are attached to a protein scaffold, which loops even further. Finally this compact structure forms chromosomes. The human has 46 chromosomes in each human body cell. They become visible through a microscope during cell division.
The nucleus also contains one or more structures called nucleoli. These produce particles called ribosomes which are exported to the cytoplasm outside the nucleus. Suspended within the semi-fluid medium outside the nucleus are many different organelles, tiny bodies with specialized functions. An intricate network of tiny tubes and sacs provides pathways for orderly transport. A few of the organelles are mitochondria, lysosomes, and the golgi apparatus. Of course, this brief description of cell structure is inadequate to convey its complex and wonderful beauty.
This discussion is not meant to prepare you for an exam on cell structure. It may, however, trigger a greater measure of appreciation for the structures manifest in nature, an important goal science educators share in addition to their lofty goal of imparting science literacy. More specifically, the many structures of the human body and, indeed, all living things, are evidence of design activity triggering our thoughtful contemplation: Who designed the structures? How did they come to be?
Curiosity about the natural world is often innate, especially among children. Natural enthusiasm sometimes wanes as the concerns and interests of teenagers and adults shift focus. Pastors and religious educators, however, could become more effective in presenting the wonders of structure and apparent design in our environment. Their goal should be not only to stimulate appreciation of structure for its own sake, but also to foster appreciation of the Designer.
