= Biological cell
{wiki=Cell_(biology)}
= Cell
{synonym}
A <biological cell> is a membrane-bounded basic unit of living organization. In a cell-level experiment it can be an <experimental unit>, provided that treatment assignment and relevant interactions are handled at that level.
The shared architecture of cellular life combines a selective <cell membrane>, internal <cytoplasm>, inherited information in <DNA>, and <ribosomes> that assemble <proteins>. <Metabolism> supplies transformations of matter and <energy> needed for maintenance and growth. These components form a coupled system: a boundary retains useful <molecules>, <enzymes> organize <chemical reactions>, and inherited information supports rebuilding the machinery. See https://openstax.org/books/biology-2e/pages/4-2-prokaryotic-cells[Clark, Douglas and Choi, Biology 2e: prokaryotic cells].
A worked structural comparison: in a typical <prokaryote>, <DNA> occupies a region without a surrounding <cell nucleus>; in a typical nucleated <eukaryote>, much of the <DNA> lies inside a membrane-bounded <cell nucleus>. Both still have a <cell membrane>, <cytoplasm> and <ribosomes>. The extra boundary compartmentalizes processes; it does not create a different basic principle of living organization. See https://openstax.org/books/biology-2e/pages/4-3-eukaryotic-cells[Clark, Douglas and Choi, Biology 2e: eukaryotic cells].
\Image[/cell-compartments.png]
{title=Shared cellular architecture with different DNA compartmentalization}
{description=Original simplified schematics of a <prokaryote> and a nucleated <eukaryote>. Colors identify corresponding components; sizes and component counts are illustrative, and additional structures are omitted.}
Shared architecture describes cellular life and its developmental machinery, rather than requiring every specialized <biological cell> to retain every component. A mature mammalian <red blood cell>, for example, lacks a <cell nucleus>, although it develops from nucleated precursors. See https://openstax.org/books/biology-2e/pages/40-2-components-of-the-blood[Clark, Douglas and Choi, Biology 2e: components of blood]. This distinction makes cellular unity compatible with striking specialization.
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