Question

Choose the correct answer from the alternatives given.
If a photosynthesizing plant evolves isotopic oxygen ${(}^{18}$$0_2)$, it can be inferred that the plant has been supplied with

• A. glucose containing ${}^{18}O$
• B. water containing ${}^{18}O$
• C. carbon dioxide containing ${}^{18}O$
• D. oxygen in the form of ozone

Answer 1

The correct option is B water containing ${}^{18}O$

This chemical energy is used in the photosynthetic reaction centers to split 2 water molecules, producing 4 electrons, 4 protons, and 2 oxygen atoms, which combine to form oxygen gas.

In 1941, the isotope of oxygen O${}_1$$-8$, was used to find out where the oxygen atoms went in photosynthesis. The scientist supplied plants with water containing O${}_1$${}_8$ . Then the O${}_1$${}_8$ was found in the oxygen gas produced by the plant but was NOT found in the sugars formed during photosynthesis. this concluded that the water containing O${}_1$${}_8$ was supplied to the plant. So the correct option is 'water containing ${}^1$${}^8$O'.