西班牙文（西班牙語）題庫下載題庫

     The first person to use the term “cell” was Robert Hooke (1635-1703) of England, who was interested in how things looked when magnified. He chose to study thin slices of cork from the bark of a cork oak tree. He saw mass cubicles fitting neatly together, which reminded him of the barren rooms in a monastery. Hence, he called them cells. As it is currently used, the term “cell” refers to the basic structural unit that makes up all living things. When Hooke looked at cork, the tiny boxes he saw were, in fact, only the cell walls that surround the living portions of plant cells. 

     We now know that the cell wall is composed of the complex carbohydrate cellulose, which provides strength and protection to the living contents of the cell. The cell wall appears to be a rigid, solid layer of material, but in reality it is composed of many interwoven strands of cellulose molecules. Its structure allows certain large molecules to pass through it readily, but it acts as a screen to other molecules. Hooke’s use of the term cell in his publication, Micrographia, was only the beginning, for nearly 200 years passed before it was generally recognized that all living things are made of cells and that these cells can reproduce themselves.