Where would you expect to find electron transport chains in a prokaryote?

The electron transport chains in a prokaryote can be found along in the plasma membrane.

Explanation:

The electron transport chain is the arrangement of transportation of electrons in the inward mitochondrial district. This procedure is the major O2 buyer. This chain passes the electrons from NADH to atomic oxygen through the ATP synthase activity.  

The chain likewise connects the electron to protein buildings. Since this Atomic oxygen is the last component that gets the electron in the electron transport chain.

So finally, the explanation is you need oxygen, so your phones can utilize this atom during oxidative phosphorylation, the last phase of cell breath.