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The Cell

A cell is often referred to as the primary unit of life, since it is this entity that serves as the functional and structural unit of all living organisms, regardless of size, complexity or purpose. Cells make up humans (known as multicellular organisms) in whom they number in the billions, just as integrally as they make up bacteria in whom they are comprised of one (known as single cell or unicellular organisms). All cells reproduce by cell division and employ proteins to perform their functions. Cells in multicellular organisms go through a process referred to as differentiation, through which a single totipotent cell initiates a process of division and transforms into whatever number of specialized cell types are needed by a particular organism to develop the inherent characteristics that define its species.

Cells can be classified into three domains: Eukaryota, Eubacteria, and Archaea. All multicellular animals (and some unicellular organisms) are Eukaryota, including humans. Eukaryota are larger and more complex than Eubacteria and Archaea and are characterized by several structural features: 1) DNA is contained within the nucleus, 2) Possesses a cytoskeleton and 3) Contain organelles such as the mitochondria.

It is within the cell that vital functions are performed, and it is also within the cell that heredity is contained so as to be passed on. Dysfunctional cells are often responsible for the occurrence of potentially lethal diseases such as cancer. Though different from one another, cells do have certain shared traits such as reproduction via division, synthesis of proteins, and the ability to react to external stimuli via signal transduction.

Web Resources On The Cell

Life and Health of Cells
What is a Cell?

Book Resources On The Cell

The Cell: A Molecular Approach by Geoffrey M. Cooper, Robert E. Hausman
Molecular Biology of the Cell by Bruce Alberts, et al

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