The diagram is schematic representation of the electron transport mechanism in mitochondria. label the diagram to complete the model.

The big blue area is the mitochondrial matrix. This is where the citric acid cycle takes place; also known as the Krebs cycle or Tricarboxylic acid cycle. The orange, green, and red shapes are (possibly) the complexes I, III, and IV respectively. At Complex IV (red), O2 or oxygen enters and H20 or water comes out as by product. The + (plus signs) are the protons which can be depicted as H+ in some diagrams. These + / protons drive the ATP synthase (yellow) to sort of turn around like a motor; and with every turn, ADP combined with inorganic phosphate (Pi in some diagrams) comes out as ATP -- the energy currency of the cell.