MECHANISMS OF ION TRANSPORT 



43 



-an 



on — 



co- 



la) 



t 



(ii) 



(b) 



-o 

 o 



O- I 



66666 

 99W9 



o- 

 o- 



(c) 



W 



o- 



(d) 



o- 

 o 

 o- 



(i) 



o 



o>p^^ 

 o- 



o 



(iii) 



(e) 



o 

 o 



o 



(iv) 



Fig. 12. Hypothetical mechanisms of ion transport across membranes. 



Ions are indicated O. 



a. Diffusing carriers; b. Rotating carriers; c. Sliding carriers; d. Propelled 



carriers (as suggested by Goldacre and Lorch, 1950); e. Membrane vesicula- 



(as suggested by Bennett, 1956). 



