How to Planes Game Energy Mechanism of Photosynthesis Part 1 How to Planes Game Energy? By the end of this video, you will be able to explain the process of light reaction in photosynthesis. Give reason why it is called as light reaction. State the connecting substances between light reaction and dark reaction. In the earlier videos, several times we have defined the process of photosynthesis with an equation such as 602 plus 12H2O, GUSRICTO C6H12O6 plus 6V2 plus 6H2O. Is it so simple as shown in the equation? No. It is a very complex process involving two stages such as light reaction and dark reaction. In this video, we are going to learn about light reaction. Before going into the light reaction, let us list out the pigments involved in the light reaction. They are chlorophyll A, chlorophyll B, keratinoyts and sandophils. These are the major pigments which are involved in the light reaction. Light reaction A series of chemical reactions occur initiated by light, so it is known as photochemical phase or light dependent reaction. It occurs in granite of chloroplas, which constitutes of stalks of thylacoids. The earlier said pigments are embedded in the thylacoid membrane in the form of light harvesting complex at many points. There are majorly three events are involved in this process. Absorption of light, photolosis and conversion of light energy into chemical energy. Absorption of light It is made possible by the light harvesting complex in which chlorophyll A forms reaction center. Whereas other pigments such as chlorophyll B, keratinoyts and sandophils remain as accessory pigments. All these accessory pigments act as antennae because when the light falls on the complex in the form of photons, the light energy is harvested cumulatively to the reaction center. Due to which the electrons are excited in the reaction center or chlorophyll A. On the basis of absorption of frequency of light, two types of photo systems are formed with the light harvesting complex such as photo system 1 and photo system 2. Photosystems When the electrons are excited from the chlorophyll, it will be received by electron acceptors such as fio-fighting. This action stimulates the water molecule to split and form oxygen, protons and electrons. This process is known as photolosis. The resultant electrons move towards the reaction center to reduce it. Conversion of light energy into chemical energy. The electrons received by the electron acceptors move through the electron transport chain which constitutes of plastic winone, cytochrome complex, plastocyanin etc. And finally, it reaches photo system 1 and reduce it, where as it is already oxidized by release of electrons due to the absorption of light. During this electron transport chain, protons are formed. Electrons which are excited by the PS1 will be received by ferrooxin. And in the presence of NADP oxidoreductase enzyme will be utilized to form NADP H which is considered as energy rich compound and utilized in the dark phase or kelvin cycle. The protons which are formed during the photolosis and during the electron transportation will be transferred through the ATP synthase complex which results in combining inorganic phosphate with the adenosine diphosphate to form ATP. Adenosine triphosphate which is again a energy rich compound. These two energy rich compound such as NADP H and ATP are the final results of light reaction which are used in the process of dark reaction. This is how the photochemical phase is represented in the thylacoid membrane involving photocystam 2 and photocystam 1. Finally, it is concluded that due to the transportation of electrons, NADP H is formed, whereas transportation of protons results in formation of ATP. As per the chemical equation, 12 molecules of water are involved in the formation of 1 molecule of glucose. So in light reaction, 12 water molecules are involved to form 6 molecules of oxygen, 12 molecules of NADP H and 24 molecules of ATP. The oxygen is released into the atmosphere, whereas NADP H and ATP are utilized in the dark phase. Hence, these two are considered oes connecting substances between light reaction and dark reaction. With this video, we have listed the pigments involved in light reaction. Let's find the events in light reaction as well as stated that NADP H and ATP are the connecting substances between light reaction and dark reaction.