Question

describe formation of proton gradient caused by electron transfer in mitochondria, chloroplast & bacteria

Answer 1

When the non cyclic and cyclic electron transfer takes place then the free protons i.e,
                      non cyclic-6 protons
                      cyclic-4 protons
these protons get accumulated in the lumen of thylakiod and creates a proton pressure that is proton gradient.Across the membrane of the thylakoid there is a portion in which the proton gradient is broken down and that portion is divided into two parts :-
   (i) F1 portion - Here the protons are passed on to the next                                                    portion.
   (ii) F2 portion(ATPsynthase or ATPase) - 
                                the proton gradient which is received from the F0 is               now converted into ATP.
                     
                  3 protons → 1 ATP.  
* Usually the same phenomenon occurs in mitochondria but takes place in cistrae