Cells, which is currently a very common phrase in our society (think cell phones, cellular devices, and…sperm cells) initially described the habitable zones for Christian monks back in the 17th century. However, an inquisitive scientist by the name of Robert Hooke, with the aid of a simple microscope, [mistakenly] gave new meaning to the word cell. While observing the outer the layers of a cork, Hooke identified objects that looked hollow and compact, similar to that of the monks that stayed in the dormitories belonging to the Christian Churches.
However, what Hooke was observing was the ‘cell’ wall of a plant, Quercus suber . The image of the plant cell he was observing, lacked a nucleus and any other organelle.
Two centuries later, Theodor Schwann, (think Schwann cells) pronounced a unifying theory of cells. He (along with the help from Matthais Schleiden) described plant and animal cells as having a nuclei. In the same century, scientists also identified other types of cells, this included the egg and germ cells, and a few organelles.
Gradually, the word cell started to become a hallmark of Biological investigations, which lead to the establishment of a unified theory on cells. The (modern) cell theory states that:
- all living organisms are made up of cells
- all cells are derived from preexisting cells
- cells are the structural and functional unit of all living things
- all cells are the same in chemical composition.