Transport of ADP in and ATP out of mitochondria is inhibited by-
Ans is 'a' i.e. atractyloside uAtractyloside inhibits oxidative phosphorylation by inhibiting the transporter of ADP into and ATP out of the mitochondrion HarperADP and Pi needs to be transported from the cytosol (where ATP is used for producing energy and converted into ADP) into the mitochondrion, where ATP is resynthesized. Since the inner mitochondrial membrane is impermeable to most charged or hydrophilic substances, a transporter is needed for the job. This transporter is strongly inhibited by atractyloside, a plant toxin, resulting in cessation of ATP production.Inhibitors of Electron Transport chainInhibit complex IInhibit Complex IIIInhibit Complex IVInhibit Complex IIRotenone- a fish poison and an insecticide Amobarbital (amytal) and Secobarbital Piericidin AAntimycin A BAL (Dimercaprol)CyanideCarbon monoxide Hydrogen sulphide Sodium azideMalonate - inhibits succinate dehydrogenaseInhibitors of Oxidative phosphorylation Oligomycin- oligomycin inhibits ATP synthase by blocking its proton channel, which is necessary for oxidative phosphorylation of ADP to ATP.Atractyloside- blocks the ADP-ATP transporterBongregate- toxin produced by pseudomonads, acts similar to atractyloside Uncouplers of Oxidative phosphorylation Uncouplers 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. Thus mitochondria uses oxygen regardless of whether ADP and Pi available or not. Uncouplers markedly increase oxygen uptake. A TPs are not being formed, rather energy is being released as heat. Thermogenin - Thermogenin (or the uncoupling protein, UCP1) is a physiological uncoupler found in brown adipose tissue that functions to generate body heat, particularly for the newborn and during hibernation in animals 2,4 dinitrophenol- is the most frequently used, classic uncoupler.Aspirin in high doses (other salicylates) - this explains the fever due to toxic overdoses of these drugs Dicoumarol (vitamin K analogue)CCCP (chloro carbonyl cyanide phenyl hydrazone)CalciumValinomycin
atractyloside
oligomycin
rotenone
cyanide
Respiratory Chain