What are the steps involved in photosynthesis of plant?
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The light-dependent reactions and the Calvin Cycle are the two main stages of photosynthesis in plants.
Light-dependent Reactions
The first stage of photosynthesis is the light dependent reactions. These reactions take place on the thylakoid membrane inside the chloroplast. During this stage light energy is converted to ATP (chemical energy) and NADPH (reducing power).

Light-dependent Reactions
Light is absorbed by two Photosystems called Photosystem I (PSI) and Photosystem II (PSII). These protein complexes contain light harvesting chlorophyll molecules and accessory pigments called antenna complexes. The photosystems are also equipped with reactions centers (RC). These are complexes of proteins and pigments which are responsible for energy conversion. The chlorophyll molecules of PSI absorb light with a peak wavelength of 700nm and are called P700 molecules. The chlorophyll molecules of PSII absorb light with a peak wavelength of 68Onm and are called P68O molecules.
The light dependent reactions begin in PSII.
A photon of light is absorbed by a P680 chlorophyll molecule in the light harvesting complex of PSII.
The energy that is generated from the light is passed from one P680 chlorophyll molecule to another until it reaches the reaction center (RC) of PSII.
At the RC is a pair of P680 chlorophyll molecules. An electron in the chlorophyll molecules becomes excited as a result of a higher level of energy. The excited electron becomes unstable and is released. Another electron is released following the capture of another photon of light by the light harvesting complex and the transfer of energy to the reaction center.
The electrons are transported in a chain of protein complexes and mobile carriers called an electron transport chain (ETC). Plastoquinone is the mobile carrier that transports the electrons from the reaction center of PSII to the Cytochrome b6f Complex as shown in the diagram above.
The electrons lost from PSII are replaced by splitting water with light in a process called Photolysis. Water is used as the electron donor in oxygenic photosynthesis and is split into electrons (e-), hydrogen ions (H+, protons) and oxygen (O2). The hydrogen ions and oxygen are released into the thylakoid lumen. Oxygen is later released into the atmosphere as a by-product of photosynthesis.
While the electrons pass through the ETC via Plastoquinone, hydrogen ions (protons) from the stroma are also tranferred and released into the thylakoid lumen. This results in a higher concentration of hydrogen ions (proton gradient) in the lumen.
As a result of the proton gradient in the lumen, hydrogen ions are transferred to ATP synthase and provide the energy needed for combining ADP and Pi to produce ATP.
Cytochrome b6f transfers the electrons to Plastocyanin which then transports them to Photosystem I.
The light-dependent reactions and the Calvin Cycle are the two main stages of photosynthesis in plants.
Light-dependent Reactions
The first stage of photosynthesis is the light dependent reactions. These reactions take place on the thylakoid membrane inside the chloroplast. During this stage light energy is converted to ATP (chemical energy) and NADPH (reducing power).

Light-dependent Reactions
Light is absorbed by two Photosystems called Photosystem I (PSI) and Photosystem II (PSII). These protein complexes contain light harvesting chlorophyll molecules and accessory pigments called antenna complexes. The photosystems are also equipped with reactions centers (RC). These are complexes of proteins and pigments which are responsible for energy conversion. The chlorophyll molecules of PSI absorb light with a peak wavelength of 700nm and are called P700 molecules. The chlorophyll molecules of PSII absorb light with a peak wavelength of 68Onm and are called P68O molecules.
The light dependent reactions begin in PSII.
A photon of light is absorbed by a P680 chlorophyll molecule in the light harvesting complex of PSII.
The energy that is generated from the light is passed from one P680 chlorophyll molecule to another until it reaches the reaction center (RC) of PSII.
At the RC is a pair of P680 chlorophyll molecules. An electron in the chlorophyll molecules becomes excited as a result of a higher level of energy. The excited electron becomes unstable and is released. Another electron is released following the capture of another photon of light by the light harvesting complex and the transfer of energy to the reaction center.
The electrons are transported in a chain of protein complexes and mobile carriers called an electron transport chain (ETC). Plastoquinone is the mobile carrier that transports the electrons from the reaction center of PSII to the Cytochrome b6f Complex as shown in the diagram above.
The electrons lost from PSII are replaced by splitting water with light in a process called Photolysis. Water is used as the electron donor in oxygenic photosynthesis and is split into electrons (e-), hydrogen ions (H+, protons) and oxygen (O2). The hydrogen ions and oxygen are released into the thylakoid lumen. Oxygen is later released into the atmosphere as a by-product of photosynthesis.
While the electrons pass through the ETC via Plastoquinone, hydrogen ions (protons) from the stroma are also tranferred and released into the thylakoid lumen. This results in a higher concentration of hydrogen ions (proton gradient) in the lumen.
As a result of the proton gradient in the lumen, hydrogen ions are transferred to ATP synthase and provide the energy needed for combining ADP and Pi to produce ATP.
Cytochrome b6f transfers the electrons to Plastocyanin which then transports them to Photosystem I.
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What is Photosynthesis?
It's the Process by which autotrophs take in substances from the outside and convert them into stored form of energy.
Steps involved in Photosynthesis
1) Absorption of light energy by chlorophyll
2) Conversion of this Light energy to chemical energy and also splitting of water molecules into hydrogen and oxygen.
3) Reduction of Carbon Dioxide to carbohydrates
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