Cells

Cells are some of the smallest organisms around. All living things consist of cells, and yet they are invisible to the naked eye. How and why are they so small? Well, cells are the basic structural and functional units of life. As life on earth has evolved into organisms of different species and living things, two basic laws of nature have dictated why cells have remained so small. One is simply, shorter is faster. This is true as far as diffusion is concerned and also in terms of chemical and electrical movement. By minimizing the distance between a cell s nucleus and the numerous proteins and organelles that is always regulated by the cell, a cell recives the maximum speed in which intercellular communications will take place while providing the ideal conditions for diffusion: Movement of molecules from a region of higher concentration to a region of lower concentration, a vital function in the life of a cell. Like wise, the surface area and volume of a cell are directly influential in the efficiency of the cell s nutrient absorption and waste expulsion processes. Since the cell membrane of an eukaryotic cell is its only source of nutrition, its surface area must be large enough to allow the cell s organelles to receive the material it needs or it will die. The eukaryotic cell does this by maximizing the surface area to volume ratio. By using the surface area and volume equations for a sphere you can estimate the surface area of a small cell. By modeling the growth rate of the surface area and volume of a sphere on a linear graph its easily discernible that as the size of the sphere increases the ratio of surface area to volume dramatically decreases until finally the volume of the sphere surpasses the surf ace area. Simply, by minimizing its size, a cell is maximizing the speed at which it can communicate, the rate at which diffusion can occur, and the amount of surface area at its disposal.