Assume that it is possible to label each of the molecules below with 18O a heavy isotope of oxygen. As a result of cellular respiration, water containing 18O would most quickly be detected if cells are provided with which one of the following molecules labeled with 18O? A) carbon dioxide (CO₂) B) glucose (C6H12O₆) C) molecular oxygen (O₂) D) pyruvate (C3H3O3)

Question

Quizplus · Accepted Answer

During cellular respiration, molecular oxygen (O2) is directly involved in the electron transport chain where it acts as the final electron acceptor, forming water (H2O) as a byproduct. Therefore, if 18O is incorporated into molecular oxygen, 18O-labeled water would be produced and detected most quickly.

Assume That It Is Possible to Label Each of the Molecules