Cell Theory and Cell Study The The Cell Theory cell is the basic unit of structure of all living things. All living things are made up of cells. The cell is the basic unit of function of all living things. Cells come from pre-existing cells. Exceptions to the Cell Theory These are facts that can not be explained by the Cell Theory. Viruses are not made up of cells, but they do contain genetic material. The first cell could not have arisen from a previously existing cell, Scientists don’t know the origin of the first cell. History of Cell Study Scientists did not know much about cells until the discovery of the microscope. Cells are so small they can not be seen w/o a microscope. Anton van Leeuwenhoek- Dutch naturalist (1600’s). Developed the first microscope. Robert Hooke- English (1665) was the first to develop a compound microscope. He came up with the term cell. History cont….. Robert Brown- (1831) discovered the nucleus of the cell. Matthias Schleiden- (German, around 1830’s) a Botanist, concluded that all plants were made up of cells. Theodor Schwann- (German, worked during the same time as Schleiden), studied animal cells. Concluded that animals were made up of cells. Rudolf Virchow- (1858) concluded that all new cells must come from previously existing cells. The Compound Microscope Microscopes are used to study materials that can’t be seen with the naked eye. Microscopes use two lenses (compound microscope) to increase the size of a specimen. A specimen must be thin enough for light to pass through it. The total magnification of an object is found by multiplying the magnification of the objective x the magnification of the eyepiece.