Where are the proteins of the electron transport chain located?
a) cytosol
b) mitochondrial matrix
c) mitochondrial inner membrane
d) mitochondrial intermembrane space
e) mitochondrial outer membrane

Mitochondrial inner membrane. (Ans. C)

Explanation:

Proteins of the electron transport chain present in the mitochondrial inner membrane. The electron transport chain at the inner mitochondrial membrane forms a proton gradient, which is driving the synthesis of ATP with the help of chemiosmosis.

Oxygen forms water by accepting electrons, and picking up protons, and it sits at the end of the ETC. In the absence of oxygen ETC will stop running, and chemiosmosis will no longer able to produce ATP. Cells are not able to carry out the reaction they need to function, and may die after a long period, in the absence of ATP.