It is difficult to state what is alive and what is not. Technically a cell is ‘alive’ as soon as the cell is capable of reproducing and is self sustaining. It may also be considered ‘living’ the moment it forms. In a developing embryo, as soon as the cell begins its first mitotic division it is alive, but there are arguments that could be made for gametes being alive. At what point a cell become life in a religious or philosophical sense depends on your background and what you believe.
All cells capable of sustaining themselves are alive in the organism. Some cells become so specialised that they are no longer capable of independent division, such as neurones, but are nonetheless alive
Some cells remove all of their nuclear material and are therefore not alive in our definition (e.g. Red blood cells, condrocytes that have specialised) but are still 'cells.' They were 'alive' and are not 'dead' so this blurs the line between our definitions.
There is no universal agreement as to a definition of life or ‘living’, its biological manifestations are generally considered to be organization, metabolism, growth, irritability, adaptation, and reproduction. Protozoa, which are single cell organisms, perform, in a single cell, the same life functions as those carried on by the complex tissues and organs of humans and other highly developed organisms.
The attributes of life are inherent in such minute structures as viruses, bacteria, and genes, just as they are in the whale and the giant sequoia. In seeking an understanding of life, scientists have broken down many barriers that once separated the physical sciences from the biological sciences; a result of the growth of biochemistry, biophysics, and other interrelated fields of study has been a better understanding of the composition and functioning of tissues of all kinds.
All cells capable of sustaining themselves are alive in the organism. Some cells become so specialised that they are no longer capable of independent division, such as neurones, but are nonetheless alive
Some cells remove all of their nuclear material and are therefore not alive in our definition (e.g. Red blood cells, condrocytes that have specialised) but are still 'cells.' They were 'alive' and are not 'dead' so this blurs the line between our definitions.
There is no universal agreement as to a definition of life or ‘living’, its biological manifestations are generally considered to be organization, metabolism, growth, irritability, adaptation, and reproduction. Protozoa, which are single cell organisms, perform, in a single cell, the same life functions as those carried on by the complex tissues and organs of humans and other highly developed organisms.
The attributes of life are inherent in such minute structures as viruses, bacteria, and genes, just as they are in the whale and the giant sequoia. In seeking an understanding of life, scientists have broken down many barriers that once separated the physical sciences from the biological sciences; a result of the growth of biochemistry, biophysics, and other interrelated fields of study has been a better understanding of the composition and functioning of tissues of all kinds.
