The Cell: A Very Short Introduction (Very Short Introductions)
Terence Allen, Graham Cowling
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In this Very Short Introduction, Terrence Allen and Graham Cowling offer an illuminating account of the nature of cells--their basic structure, forms, division, signaling, and programmed death.
Allen and Cowling start with the simple "prokaryotic" cell--cells with no nucleus--and show how the bodies of more complex plants and animals consist of billions of "eukaryotic" cells, of varying kinds, adapted to fill different roles--red blood cells, muscle cells, branched neurons. The authors also show that each cell is an astonishingly complex chemical factory, the activities of which we have only begun to unravel in the past fifty years.
Blair ANIMAL RIGHTS • David DeGrazia ANTISEMITISM • Steven Beller THE APOCRYPHAL GOSPELS • Paul Foster ARCHAEOLOGY • Paul Bahn ARCHITECTURE • Andrew Ballantyne ARISTOCRACY • William Doyle ARISTOTLE • Jonathan Barnes ART HISTORY • Dana Arnold ART THEORY • Cynthia Freeland ATHEISM • Julian Baggini AUGUSTINE • Henry Chadwick AUTISM • Uta Frith BARTHES • Jonathan Culler BESTSELLERS • John Sutherland THE BIBLE • John Riches BIBLICAL ARCHEOLOGY • Eric H.
(as will be described in Chapter 4), and the dynamic nature of the cytoskeleton becomes its main characteristic. An organized cytoskeleton is a property restricted to eukaryotes, although similar proteins do exist in a rudimentary form in some bacteria. The eukaryotic cytoskeleton is defined as a network of three types of large proteins: microtubules (formed from the smaller protein, tubulin); intermediate filaments (a group of fibrous proteins with similar properties); and microfilaments
processes of the cell they infect. Their non-vital nature is emphasized by the capacity to make crystals of purified viruses in solution. The cell is the basic unit of life, and as such must fulfil three requirements: (1) to be a separate entity, requiring a surface membrane; (2) to interact with the surrounding environment to extract energy in some way for maintenance and growth; and (3) to replicate itself. These parameters are the same for all living beings, from the smallest bacterium, to any
(neurotransmitters) between cells in a complex network extending throughout the body. Millions of sensory neurons have receptors that convert stimuli from the environment (light, touch, sound, smell) into electrical signals that feed back to the brain. Other motor neurons send information from the brain to the muscles and hormone-secreting glands. Interneurons mediate the information between the sensory and motor neurons. Neurons have specialized extensions called dendrites and axons. Dendrites
the suppression of genes that lead to differentiation. The default situation is to limit division and to differentiate. Nature has perhaps evolved an almost foolproof mechanism to protect the organism from the dangers of ES cells that evade the normal controls on growth. Germ-line stem cells generate sperm or eggs (haploid gametes) which have half the normal number of chromosomes, and transmit genetic information from one generation to the next. Such cells are easily identified, retrieved, and