Cell theory: Learn about the cell

Learn about the cell theory , its history, and its modern version. Find out the contributions of Schleiden, Schwann, and Virchow, and the merits and objections of the modern cell theory . First proposed by German scientists Theodor Schwann and Matthias Jakob Schleiden in 1838, the theory that all plants and animals are made up of cells marked a great conceptual advance in biology and resulted in renewed attention to the living processes that go on in cells. Every cell in the human body is a different type of cell . According to cell theory , each of these cells originated from the zygote, a single cell produced upon the fertilisation of an egg by a sperm. Then, this cell multiplies, divides, and starts differentiating into the various types of cells that make up the human body. What is Cell Theory ? Cell theory is a fundamental principle of biology that states all living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells. This theory highlights the importance of cells in the structure, function, and growth of all living things. It integrates concepts of biology from the microscopic to the macroscopic level, providing a unified understanding of life processes. First articulated in the mid-19th century ...