Richard Fox, age 11, of Anchorage, Alaska
What is a living cell?
A stone wall is built of stones of various, shapes and sizes. Plants and the bodies of animals are built of cells of various shapes and sizes. The stones in the wall, however, have only one job, which is to keep the wall firm and strong. The cells of plants and animals have many jobs to do. Each type of cell is a specialist. The cells which form muscles, for example, cannot do the work of the blood cells or the cells which form the shin.
These cells are too small for our eyes to see, With a strong magnifying glass, you can see the separate cells of a piece of wood. But body cells must be properly prepared and studied under a microscope. Wood cells look like little boxes tightly packed together. Actually, these are only the cell walls of wood‑making cells. The cells built them to support the tree and when the job was done they had no more reason to stay alive. Wood, then, is dead tissue, or cells. Your hair, nails, and the enamel on ,your teeth is also dead tissue.
The millions and millions of cells which make up the rest of your body are very, very much alive. Under the microscope, certain body cells differ from others and all of them differ from plant cells in shape. However, all living cells, glihether plant, animal or human have certain factors in common.
A living cell can be almost any shape, depending upon the work it has to do. It is a small unit of life filled with a jelly‑like fluid called protoplasm. There is always some kind of cell wall holding this unit of living matter together. It may be a sturdy box made of cellulose as we see in the woody plant tissue. It may be a fine skin of clear jelly surrounding the granular protoplasm within. In any case, the individual cells do not run into one another, though they= are closely hacked together like the stones in a wall.
The difference between a live and a dead cell is the magic protoplasm. This substance is composed of several common elements ‑ mainly carbon, hydrogen, oxygen, nitrogen and phosphorus. There are fine granules afloat in the paleje11y and towards the center of the cell is a small wad called the nucleus. There are also larger granules called vacuoles.
Each living cell can carry on the vital processes of life. It can use food and air, change them into energy and new protoplasm. Each living cell can divide into twin cells. It is because of this last gift of the tiny cells that our body grows and repairs itself,
The vital heart of the cell is the nucleus. Without this the cell cannot carry on its work and it cannot multiply. When a cell divides, the nucleus breaks in two, forming two identical nuclei. The vacuoles in the cells are tiny pockets where food is being transformed or digested: