MBC: Cell integrity: metabolic poisons

Question 1

What are metabolic poisons?

Answer 1

molecules that interfere with the flow of electrons along the ETC or the flow of protons through ATP synthase, therefore interrupting ATP synthesis

Question 2

List the metabolic poisons and state their effect along the ETC

Answer 2

Cyanide (CN) and Azide (N3)-have high affinity to the Fe3+ (ferric form of the ham group) in the cytochrome oxidase complex, blocking the final step of the ETC.

Malonate- similar structure to succinate therefore acts as competitive inhibitor of succinate dehydrogenase. Therefore slowing the flow of electrons from succinate to ubiquinone/ Coenzyme Q

Rotenone- inhibits electron transfer from complex I to Ubiquinone/ Coenzyme Q

Oligomycin- binds to stalks of ATP synthase, inhibiting flow of protons through the enzyme therefore inhibiting oxidative phosphorylation

Dinitrophenol (DNP)- acts as a protonophore, allowing protons to leak across the inner mitchondrial membrane therefore bypassing the ATP synthase which makes ATP synthesis less efficient