THE HISTORY OF CELL DISCOVERY_ CELL THEORY_ Pharmaceutical Biochemistry (lab)-KEROVILLOS.pdf

THE HISTORY OF CELL DISCOVERY: CELL THEORY The cell is the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed. This lesson discusses the cell both as an individual unit and as a contributing part o...

THE HISTORY OF CELL DISCOVERY: CELL THEORY The cell is the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed. This lesson discusses the cell both as an individual unit and as a contributing part of a larger organism.   THE HISTORY OF CELL DISCOVERY Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. They provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions. Cells also contain the body’s hereditary material and can make copies of themselves. The discovery of cells was quite fascinating. It involved several notable discoveries by renowned scientists during that time. 1600's Dutch lens maker, Zacharias Janssen, invented one of the microscope’s first prototypes. 1665 Robert Hooke reported some first clear drawings of the plant cells he had observed in thin cells of cork. He first coined the term “cell” reminded him of the many box-like structures (blocks of cells) occupied by the monks.  1673 Antonie van Leeuwenhoek reported his discovery of blood cells, sperm cells, and a lively world of “animalcules” which were later found to be bacteria and protozoans. Also, he created his own powerful microscope. The cell theory was only formulated after nearly 200 years since the introduction of microscopy.  1779-1851 Lorenz Oken postulated in 1805 that all organisms originate from and consist of cells. This became the initial statement of the modern cell theory. Three significant discoveries during the 1830’s led to the early development of the cell theory. 1833 Robert Brown discovered the nucleus as a constant part of the plant cell. Then the nuclei were also found and observed in some animal cells.  1835 French biologist Felix Dujardin, first recognized the living substance within the cell which he termed as sarcode. This term was later changed to protoplasm by a Czech physiologist Jan Evangelista Purkinje, referring to the colloidal substance in the cell. 1838-1839 German botanist Matthias Jakob Schleiden and German zoologist  German botanist Matthias Jakob Schleiden and German zoologist Theodore Schwann concluded that cells are the elementary particles of both plants and animals. They noted that some organisms are unicellular while the others are multicellular. 1858 German pathologist, Rudolf Virchow concluded that cell is the basic and structural unit of life and that every cell is formed from a preexisting cell.   THE CELL THEORY The modern cell theory includes the following three principles: 1. All organisms are composed of one or more cells. 2. Cells are the basic unit of organization of all organisms. 3. Cells arise only by division of a previously existing cell.