<prompt> Uncoupler in ETC -H2SAntimycin a2,4-dinitrophenolBarbiturates  <response>: Ans. C. 2, 4-dinitrophenolUncouplers of oxidative phosphorylation in mitochondria inhibit the coupling between the electron transport and phosphorylation reactions and thus inhibit ATP synthesis without affecting the respiratory chain and ATP synthase H- ATPase. Physiological uncouplers- long chain fatty acids, thyroxin, calcium ions, brown adipose tissue Pathological uncouplers-2,4 dinitrophenol, 2,4 dinitroocresol, CCCP, FCCP, valinomycin, high dose aspirinClass with examplesAffected complex or reactionInhibitors of electron transport Rotenone, Piericidin AAmytal, SeconalThenoyltrifluoroacetoneAntimycin A.DimercaprolHCN, H2 SHN3 , COI FMN-Q and or cytbFe3I FMN-Q and or cytbFe3II Peptide-FAD-Q andor cytbIII cytbFe2-cytclFe3perhaps at NHIIV cytcFe2-O2 IV cytcFe2-O2 Inhibitors of oxidative phosphorylation OiigomycinRutamycinAtractylateBongkrekateInhibit respiration NADH-O2 or Succinate O2 when coupled to phosphorylationUncouplers of oxidative phosphorylation2,4 dinitrophenolDicoumarolValinomycin Gramicidin A Stimulate respiration when rate is limited by phosphorylation or blocked by oiigomycin. 