Which of the following products of light reaction diffuses out of the chloroplast?

Correct option is B

The correct answer is (B) O2

Explanation:
• The light reaction of photosynthesis occurs in the thylakoids of the chloroplast.
• It produces ATP, NADPH, and O2 (Oxygen).
• ATP and NADPH are high-energy molecules that remain in the stroma of the chloroplast to be used in the Dark Reaction (Calvin Cycle) to synthesize sugars.
• Oxygen (O2) is produced as a by-product of the photolysis of water and diffuses out of the chloroplast into the atmosphere.

Information Booster:
• Photolysis of Water: The splitting of water molecules (H2O) in the presence of light releases electrons, protons (H+), and Oxygen.
• Site: Light reaction happens in the Grana/Thylakoids, while Dark reaction happens in the Stroma.

Additional Knowledge:
• ATP & NADPH (Options C & D): These represent the 'Assimilatory Power' and are consumed within the chloroplast for glucose synthesis.
• H2O (Option A): Water is a reactant (raw material) in the light reaction, not a product that diffuses out.