Which one of the following statements about the process of photosynthesis is correct ?

Photosynthesis involves several key biochemical events. First, light energy is absorbed by chlorophyll and converted into chemical energy (ATP and NADPH), not the reverse [1]. During this light-dependent phase, water molecules undergo photolysis, where they are split into hydrogen (protons), electrons, and oxygen [1]. While light energy drives this process, it is the reaction center acting as an oxidizing agent that causes the split, rather than light directly 'cutting' the molecule. In the subsequent light-independent phase (Calvin cycle), carbon dioxide is reduced to form carbohydrates like glucose [1]. Oxidation involves the loss of electrons, which occurs to water, while reduction involves the gain of electrons, which occurs to carbon dioxide. Therefore, the statement that water molecules split into hydrogen and oxygen is the most accurate description of a core photosynthetic process.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > QUESTIONS > p. 82