Yet, small as it is, the cell exhibits all of the customary phenomena of independent life; that is to say, it nourishes itself, it grows, it reproduces its kind, it moves about, and “it feels”. It is a “living, breathing, feeling, moving, feeding thing”.
The term “cell” suggests a walled-in enclosure. This is because it was originally supposed that a confining wall or membrane was an invariable and essential characteristic of cell structure. It is now known, however, that while such a membrane may exist, as it does in most plant cells, it may be lacking, as is the case in most animal cells.
The only absolutely essential parts of the cell are the inner “nucleus” or kernel and the tiny mass of living jelly surrounding it, called the “protoplasm”.
Tags: living cells