Cell theory is one of the most fundamental theories in biology. It states that all living things are composed of cells, that cells are the basic unit of life, and that cells come only from pre-existing cells. Since its inception in the mid-1800s, numerous experiments have been conducted to expand on the original cell theory. This article will explore which experiments have led to changes to the original cell theory.
Overview of Cell Theory
Cell theory was first proposed in 1838 by two German scientists, Matthias Schleiden and Theodor Schwann. They suggested that all living things are composed of cells, that cells are the basic unit of life, and that cells come only from pre-existing cells. This theory was then expanded upon by Rudolf Virchow in 1855, who suggested that cells can only arise from the division of existing cells.
Experiments that Led to Changes
The first experiment to influence the original cell theory was conducted in 1875 by German biologist Walther Flemming. He observed that chromosomes divide during cell division, a process he called mitosis. This experiment showed that cells are capable of self-replication, and paved the way for further research into the genetic material of cells.
In 1931, British biologist Ernest Everett was able to show that DNA is the genetic material of cells. This experiment contradicted the original cell theory, which suggested that proteins were the genetic material. This discovery revolutionized the field of biology and marked the beginning of the era of molecular genetics.
Another experiment that changed the original cell theory was conducted in 1953 by American biologist James Watson and British biologist Francis Crick. They were able to determine the structure of DNA, a double helix. This experiment showed how genetic information is stored and passed on from one generation to the next.
Finally, in 1965, American biologist Sydney Brenner conducted an experiment that showed that DNA is transcribed into RNA, which is then translated into proteins. This discovery showed that proteins are not the genetic material, as suggested by the original cell theory.
Cell theory is one of the most fundamental theories in biology. Since its inception in the mid-1800s, numerous experiments have been conducted to expand on the original cell theory. This article discussed the experiments that have led to changes to the original cell theory, including experiments conducted by Walther Flemming, Ernest Everett, James Watson and Francis Crick, and Sydney Brenner. These experiments have revolutionized the field of biology and continue to shape our understanding of the cell.
Since its initial formulation over 170 years ago, the Cell Theory has been a cornerstone of biology. Developed in 1839 by German biologists Matthias Jacob Schleiden and Theodor Schwann, the Cell Theory states that all living organisms are composed of cells, cells are the basic building blocks of life, and all cells arise from pre-existing cells. Despite its prominent position, the Cell Theory has evolved over time as a result of the experiments and observations of numerous scientists. Here, we review how several of the most influential of these experiments ultimately led to changes to the original Cell Theory.
One of the more significant contributions to the Cell Theory came from the French biologist Claude Bernard in the 1850s. Bernard was the first to argue that all cells processes are driven by subtle internal changes. His artificial production of cells from preexisting cells ushered in a new era of cellular biology, a notion that all cell functions ultimately depend on alterations of some form inside the cells themselves.
Subsequent experiments built upon Bernard’s ideas and in 1874, the German biologist Rudolph Virchow argued that all cells arise from preexisting cells. He asserted that “Omnis cellula e cellula,” meaning all cells come from cells. This finality introduced the concept that all life has a unified cellular origin, and it is through cell division that life is perpetuated.
Further experiments made during the late 1800s and early 1900s changed our perception of cells and their ability to survive and multiply. The German biologist August Weismann in 1887 showed that cells remain constant across generations and the Dutch botanist Hugo de Vries in 1896 proposed the concept of ‘Mutation’, where during the process of cell division, changes can be introduced into the genetic information in a cell.
Lastly, the German zoologist, and Nobel laureate, Christian de Duve in 1975 introduced the idea of organelles, which are microscopic organs within cells that perform specific functions of the cell. Organelles contain membranes that separate them from the cell and from each other, having been introduced by the genetic information of a mother cell.
Overall, experiments and observations conducted by a wide range of scientists have led to the evolution of the Cell Theory. By introducing the theories of artificial cell production, unified cellular origin, cell constancy and cell mutation, as well as the existence of cellular organelles, the initial Cell Theory of 1839 has been developed into a wider understanding of the greater purpose of cells in the origin, maintenance, and evolution of life.
