Universal Properties of All Cells:
 
        1.  store their hereditary information in a linear DNA molecular code
         2.  replicate their hereditary information by templated polymerization
         3.  transcribe hereditary information into RNA intermediate
         4.  translate RNA into protein by same mechanisms
                     - a fragment of hereditary information for 1 protein is 1 gene
                     - small cells can have fewer than 500 genes
                     - new genes come from preexisting genes via intragenic mutations,
                              gene duplications, fragment shuffling, and intercellular transfers.
         5.  use proteins as catalysts
         6.  life (cells) require free energy -  free energy sources for cells include: 
                     - heterotrophy (foods),  phototrophy (light), and
                        lithrotrophy (inorganic reactions)
                     - some cells can fix N
2  -->  NH2  & some can fix CO2 --> CH2O
          7. use same molecular building blocks for biochemical reactions
          8. are enclosed by an amphiphatic lipid plasma membrane

kidney epithelia with microtubules - C.Fagerstrom & P. Wadsworth, Biology @ U.Mass
3D tomogram of yeast by EMBL & U. Colorado; Hoog et al 2007
cerebellar granule cells by confocal microscopy by L. Collin
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