Cell Theory and Cell as the Basic Unit of Life

Cell theory was first formulated in the 1939. The theory proposed is known as the classical cell theory, and cell as the basic unit of life was its main proposal. This means that the theory proposed some basic concepts which stem from this basic assumption. Later on, the modern cell theory added other concepts to include modern research relating to genetics.

Classic Cell Theory

Theodor Schwann and Matthias Schleiden submitted the cell theory in 1939. The first two parts of the theory were based on the conclusions of the observations of work done by  Schwann and Schleiden in 1938 , and Rudolf Virchow gave the third part in 1858. They are as follows: 

•     All living things are made up of cells
•     Cells are the basic structural and functional unit of life
•     All cells originate from pre-existing cells i.e “Omnis cellula e cellula”

Cell theory and cell as the basic unit of life are concepts that have been associated together since the earliest days of cell theory.

Modern Cell Theory

With the advancement in scientific technology, new knowledge has come to light. This has led to fresh conclusions, so three more tenets have been added to the cell theory. They are as follows:

•     Cells contain DNA and RNA, and when cells divide, their genetic material is also divided and passed between cells
•     The cells of organisms of similar species are structurally and chemically similar
•     Flow of energy (biochemical reactions including those required for metabolism) happens inside cells

Discovery of Cells

The discovery of cells was made possible by the invention of the microscope. It began with the invention of glass by the Romans in 1st century BC. They also found that objects appear larger when seen through glass. In the 12th century, an Italian, Salvino D’Armate, fitted a piece of glass over an eye and found that it produced a magnifying effect. This propelled the use of simple microscopes (mainly magnifying glass). By 1620, the compound microscope had been invented in Europe, with much higher magnification. Anton van Leeuwenhoek was able to make a single cell microscope with a magnification of up to 270x.

A modification of van Leeuwenhoek’s model, Robert Hooke’s microscope, had a magnification of 300x. Using this, Hooke observed a thin slice of cork and found that it was made of boxlike structures that reminded him of the cells of monks. That is why he called them cells. The description of these, along with others, can be found in Microphagia, the book Hooke wrote recording all his observations. Thus began the first steps towards discovering the cell theory and cell as the basic unit of life.

Cell Theory and Cell as the Basic Unit of Life

Cell theory states that cells are the basic structural unit of all living organisms. It is through cells that other functional structures of the organism are formed. In higher-order organisms, cells that share an origin are similar in structure and perform the same function. They group together to form tissues. These tissues combine together to form an organ, such as the heart or the kidneys. The organs group together form organ systems such as the excretory or digestive systems. Organ systems function together to form an organism.

Cells are mainly grouped into two types:

•     Prokaryotes are the more primitive type of cells. These are mostly single-celled bacteria
•     Eukaryotes are the cells found in most higher-order organisms

Most complex organisms are made up of several kinds of eukaryotic cells.

Conclusion

Cell theory and the cell as a basic unit of life are some of the most fundamental concepts of biology. It is through the study of basic structures of living organisms that scientists are able to understand their more complex functions. Moreover, studying cells and how they work makes for a fascinating study. They perform complicated tasks within the body, and studying this fundamental structure can alleviate a lot of the problems faced by the body. The cell theory made a major breakthrough in the way scientists viewed the living world, and it continues to influence studies today.