12 THE CELL AS A PHYSICO-CHEMICAL UNIT 



sider a number of other properties of the molecular 

 types constituting the cell. The most important points 

 to be considered here are: i. the units of structure, 2. 

 the control of enzyme systems, 3. the dielectric proper- 

 ties, 4. membrane properties, 5. the dynamic condition 

 of cell constituents. 



Units of Structure. Fig. 3 shows diagrams of a number 

 of types of units of structure which will be formed by 



Adlineated chains 



Tactoid 



Leaflet 



Micelle 

 Fig. 3. Units of cellular structure 



molecules known to be present in the cell. The simplest 

 of these consists simply of adlineated polypeptide chains 

 such as are found in collagen fibres, keratin, muscle 



