Q2 - Respiratory Control in Isolated Mitochondria: ADP, DNP and DCCD
The figure 1 illustrated below shows oxygen consumption (respiration) in aqueous suspension of intact animal mitochondria with additions of ADP or chemical compounds (dinitrophenol (DNP) or N,N’- dicyclohexylcarbodiimide (DCCD)). The suspension already contains respiratory substrates, oxygen, and inorganic phosphate.
Oxygen consumption of mitochondria in suspension. Identical aliquots of ADP were added in both experiments.
Using the information and data, determine which of the statements are true or which are false.
A. The mitochondria are able to incorporate exogenously added ADP.
B. Before addition of chemical compounds, the mitochondria respire only when ATP can be produced.
C. The reason why DNP stimulates oxygen consumption is that ATP synthesis is stimulated by DNP.
D. DCCD inhibits ATP synthesis.
Question reproduced from IBO 2020, Theoretical Exam 1, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)