a) Both the mitochondrion and chloroplast contain electron transport chains. Describe  two similarities of the electron transport chains despite being located in different organelles. (2 points)

b) In the mitochondrion, the electron transport chain is normally coupled to ATP synthase. However, in endothermic animals, the electron transport chain is uncoupled from ATP synthase when temperatures drop below a certain threshold. Explain why uncoupling of the electron transport chain from ATP synthase is advantageous for an animal under cold temperature conditions. 

c) Dinitrophenol is an uncoupling compound that binds to proteins in the mitochondrial electron transport chain. DNP does not stop the flow of electrons, but it does interrupt the connection between the flow of electrons and ATP synthase. At the point of its discovery, it was suggested that dinitrophenol be developed as a weight-loss medication. Explain a possible reason for considering the compound dinitrophenol as a potential weight-loss drug.