CSB325H1 Lecture Notes - Lecture 4: Protocell, Nerve Net, Cell Signaling
18 Dec 2013
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Gases oxygen (o2), water (h2o), carbon monoxide (co), carbon dioxide (co2), methane (ch4), nitrogen (n2), ammonia (nh3) Amino acids glycine, alanine, aspartic acid, glutamic acid. Terrestrial origins: methane (ch4), ammonia (nh3), water (h2o), nitrogen (n2) will readily form amino acids, sugars, and purines. Lightning: cosmic radiation, geothermal vents, volcanic activity. A living system is characterized by an ability to reduce entropy. Physiological requirements = internal conditions: energy, raw materials. Environmental conditions = external conditions: acceptable conditions (growth/metabolism, poor conditions (quiescence) When cells can coordinate these signals, they begin to live in a community either singly or communal and begin to establish a division of labor and therefore specialization of function. Protocells partitioning of biotic (life) and non-biotic (non-life) environments in the form of a plasma membrane created the need for signalling networks. Evolution of protocells: association of organic material on inorganic substrate, concentration of organic material, partitioning of hydrophilic and hydrophobic molecules. First signalling networks: random and intermittent signaling capacity.
