Medical research

A new blood component revealed

Does the blood we thought to know so well contain elements that had been undetectable until now? The answer is yes, according to a team of researchers from Inserm, Université de Montpellier and the Montpellier Cancer Institute ...

Oncology & Cancer

The evolution of a tumor

The results of evolution are often awe-inspiring—from the long neck of the giraffe to the majestic colors of a peacock—but evolution does not always create structures of function and beauty.

Medical research

First treatment for pain using human stem cells a success

Researchers at the University of Sydney have used human stem cells to make pain-killing neurons that provide lasting relief in mice, without side effects, in a single treatment. The next step is to perform extensive safety ...

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Cell (biology)

The cell is the structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram.) The largest known cell is an unfertilized ostrich egg cell.

In 1835 before the final cell theory was developed, a Czech Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells. All cells come from preexisting cells. Vital functions of an organism occur within cells, and all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.

The word cell comes from the Latin cellula, meaning, a small room. The descriptive name for the smallest living biological structure was chosen by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.

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