Introduction

Plants are the basis of food chains on earth. They are capable of producing their own food by converting light energy into chemical energy during photosynthesis. Photosynthesis is a complex process that involves many steps, but the first step involves splitting water to obtain electrons, hydrogen ions and oxygen gas. This article explores the process of how plants split water and use the obtained electrons and hydrogen ions to produce energy-rich compounds that fuel the rest of the photosynthetic process.

Splitting of Water

Water is split during the light-dependent reactions of photosynthesis, which take place in the thylakoid membranes of chloroplasts. This process is carried out by a group of proteins called photosystem II, which work together to extract electrons from water molecules. Water is split into oxygen gas, protons (H+) and electrons (e-). The oxygen gas is released into the atmosphere, while the protons and electrons enter into the photosynthetic electron transport chain.

Photosystem II

Photosystem II is the first protein complex involved in the light-dependent reactions of photosynthesis. It consists of over 20 different proteins and pigments that work together to harness and transfer light energy. The key component of photosystem II is a special molecule called chlorophyll a, which is responsible for absorbing light energy and transferring it to other molecules within the complex. When a photon is absorbed by chlorophyll a, it excites an electron within the molecule, which is then transferred to a molecule called a quinone. This process creates a charge separation, which ultimately allows for water to be split and electrons to be extracted for photosynthesis.

Use of Electrons and Hydrogen Ions

The electrons and hydrogen ions obtained from water splitting are used by the photosynthetic electron transport chain to produce energy-rich compounds that fuel the rest of the photosynthetic process. As the electrons move through the chain, they release energy that is used to pump protons across the thylakoid membrane, creating a proton gradient. This gradient is then used by a protein complex called ATP synthase to produce ATP, which is the main source of energy for the rest of the photosynthesis process. Additionally, some of the electrons are used to produce another energy-rich molecule called NADPH, which is also used in the rest of the photosynthesis process.

Conclusion

Plants are able to split water to extract electrons and hydrogen ions, which are used to produce energy-rich compounds that fuel the rest of the photosynthesis process. This process is carried out by a complex set of protein and pigment molecules, with the key player being photosystem II. Understanding how plants split water and use the obtained electrons and hydrogen ions is critical to understanding the fundamental basis of life on earth.