Cell Theory/ Solar System/ Photosynthesis

Cell Theory

In biology, cell theory is a scientific theory that describes the properties of cells, the basic unit of structure in every living thing. The initial development of the theory, during the mid-17th century, was made possible by advances in microscopy; the study of cells is called cell biology. Cell theory is one of the foundations of biology. The three parts to the cell are as described below:
1. All living organisms are composed of one or more cells.
2. The cell is the basic unit structure, function, and organization in all organisms.
3. All cells come from pre-existing, living cells.
The cell was discovered by Robert Hooke in 1665. He examined (under a coarse, compound microscope) very thin slices of cork and saw a multitude of tiny pores that he remarked looked like the walled compartments a monk would live in. Because of this association, Hooke called them cells, the name they still bear. However, Hooke did not know their real structure of function. Hooke’s description of these cells (which were actually non-living cell walls) was published in Micrographia. His cell observations gave no indication of the nucleus and other organelles found in most living cells.
The first person to make a compound microscope was Zacharias Jansen, while the first to witness a live cell under a microscope was Anton van Leeuwenhoek, who in 1674 described the algae Spirogyra and named the moving organism’s animalcules, meaning “little animals”. Leeuwenhoek probably also saw bacteria. Cell Theory was in contrast to the vitalism theories proposed before the discovery of cells.
The idea that cells were separable into individual units was proposed by Ludolph Christian Trevianus and Johann Jacob Paul Moldenhawer. All of this finally led to Henri Dutrochet formulating one of the fundamental tenets of modern cell theory by declaring that “The cell is the fundamental