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Figure 6-5. Electron Micrograph of Collagen Fibers Carefully Lifted from Human 

 Skin. Note how they are individually cross-segmented and collectively fused (Courtesy 

 of J. Gross, Massachusetts General Hospital, and of Scientific American.) 



Lipid molecules themselves are generally small, by comparison with the 

 macromolecules discussed in this section (see Table 6-1). However, they 

 condense with proteins to form macromolecular lipoproteins, and with 

 cellulose to form lipocelluloses, and thus also play a primary role in the 

 structure of tissue. 



Metal-organic molecules are varied and important in living tissue (Table 

 6-1). The bright light from the point of view of our knowledge of structure 



