A Water Molecule can be Split by a Leaf!

One of the many remarkable things about water is that the molecule is very stable and it is hard to get the oxygen away from those two hydrogens. Yet it can be and is done routinely every day by ordinary leaves in the process of photosynthesis.

水有许多令人惊叹的特性之一是，水分子非常稳定，很难将氧从那两个氢原子中分离出来。然而，这种分离却每天都在普通叶子的光合作用过程中常规发生。

Gerald Karp waxes eloquent as he describes how difficult this achievement is. "In fact, the splitting of water is the most thermodynamically challenging (endergonic) reaction known to occur in living organisms. Splitting water in the laboratory requires the use of a strong electric current or temperatures approaching 2000°C. Yet a plant cell can accomplish this feat on a snowy mountainside using only the energy of visible light."

Gerald Karp 详细阐述了这一成就的难度。‘事实上，水的分解是已知在生物体内最热力学上具有挑战性（耗能）的反应。在实验室中，水的分解需要使用强电流或接近2000°C的温度。然而，一个植物细胞仅利用可见光的能量，就能在雪山上完成这一壮举。

This splitting of water is part of the process of photophosphorylation to change ADP to ATP, the universal energy currency for the processes of life. By extracting an oxygen from water in a two-stage process of non-cyclic electron transport, the cell can also produce enough energy for the production of carbohydrates for cellular respiration.

这种水分解是光磷酸化过程的一部分，该过程将ADP转化为ATP，这是生命过程中通用的能量货币。通过在非循环电子传递的两阶段过程中从水中提取氧，细胞也可以产生足够的能量，用于细胞呼吸中碳水化合物的生成。