14. Among the following which chemical inhibits the mitochondrial electron transport chain-
(1) Streptomycin       (2) Nystatin
(3) Azides                (4) Penicillin

 

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The mitochondrial electron transport chain (ETC) is essential for cellular energy production, transferring electrons through complexes I-IV to oxygen, the final electron acceptor. Certain chemicals can inhibit this chain, disrupting ATP synthesis and cellular respiration.

Among various inhibitors, azides are well-known for their ability to block the ETC by targeting Complex IV (cytochrome c oxidase).

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How Azides Inhibit the Electron Transport Chain

• Azides bind to the heme groups within Complex IV (cytochrome c oxidase).

• This binding prevents oxygen from attaching to Complex IV, effectively blocking the final step of electron transfer.

• Without oxygen as the terminal electron acceptor, electron flow through the ETC ceases.

• This stops proton pumping and the generation of the proton motive force, halting ATP synthesis.

• The result is cellular asphyxiation and energy failure.

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Why Other Chemicals Are Not ETC Inhibitors

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Summary

• Azides are chemical inhibitors of the mitochondrial electron transport chain.

• They specifically inhibit Complex IV by preventing oxygen binding.

• This inhibition stops electron flow and ATP production, leading to cellular energy failure.

• Antibiotics like streptomycin and penicillin do not affect the mitochondrial ETC.

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Final Answer:

(3) Azides