Question

If green plant cells are incubated with¹⁸O-labeled carbon dioxide, what molecule will become radioactive as the cells are exposed to light?

Answer 1

During the process of photosynthesis:-

6 CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

In this process water molecule splits to evolve oxygen and hydrogen atoms and CO₂ combines with some of the water molecule to give glucose (sugar).Thus, we can say that if plant cells are incubated with¹⁸O-labeled carbon dioxide then glucose molecule will contain that radioactive labeled oxygen atom.