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Asked in NUMS 2020 2020

Cyanides are potent poisons of the living organism and can kill by inhibiting _, essential for cellular respiration:

Correct answer: A. Cytochrome oxidases

  • A. Cytochrome oxidases
  • B. Dehydrogenases
  • C. Hydrolases
  • D. Nucleases

Explanation

Cyanide poisons the mitochondrial electron transport chain within cells and renders the body unable to derive energy (adenosine triphosphate-ATP) from oxygen. Specifically, it binds to the a3 portion (complex IV) of cytochrome oxidase and prevents cells from using oxygen, causing rapid death.

This question appeared on the NUMS 2020 paper, which you can sit online with every answer explained.

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About Cellular Respiration

Cellular respiration releases energy from glucose through glycolysis, the link reaction, the Krebs cycle and the electron transport chain, producing ATP. The pathway differs in oxygen availability: aerobic respiration uses oxygen and yields more ATP, while anaerobic respiration produces much less ATP and forms lactic acid in muscles or ethanol and carbon dioxide in yeast.

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