Biology PYQ 91 of 399 · Plant Physiology: Photosynthesis, Respiration & Nutrition

In how many steps is CO2 released in aerobic respiration?

  1. AOne
  2. BSix
  3. CThree
  4. DMore than one of the above
  5. ENone of the above

BPSC TRE-2 (Dec 2023)

Show answer and explanation

Correct answer: (c) Three

Explanation

In aerobic respiration, carbon dioxide is released at three steps:

  • when pyruvate is turned into acetyl CoA
  • in the Krebs cycle, when isocitrate becomes α-ketoglutarate
  • in the Krebs cycle, when α-ketoglutarate becomes succinyl CoA
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