Difference Between Light and Dark Reaction | Definition, Characteristics, Function
The chloroplast is involved in both stages of photosynthesis. The light reaction takes place in the thylakoid discs. There, water (H 2 0) is. by which green plants absorb light energy from the sun with the assistance of The "light-independent" or dark reactions happen in the stroma of the chloroplasts. The first overall principle of photosynthesis is that the light energy from the. Light reactions have to occur before the dark reactions occur.
Photosynthesis can be summarized with this formula: The "light-independent" or dark reactions happen in the stroma of the chloroplasts.
This is also known as the Calvin Cycle. Since these processes can only happen in the chloroplast a chlorophyll filled plastid in green plantsphotosynthesis can only happen in green plants!
The second overall principle of photosynthesis is that carbon, oxygen, and hydrogen atoms are taken from carbon dioxide and water molecules and are broken up and rearranged into new substances: This reaction represents the transfer of matter: Light-Dependent Reactions The first part of the process happens in the thylakoids of the chloroplasts and are the "light-dependent" reactions: The photosystems I and II absorb the photons from the sunlight and process them through the membranes of the thylakoids simultaneously.
At the same time, ADP adenosine diphosphate has come from the dark reaction and a third phosphate chain is bonded forming ATP adenosine triphosphate to feed the Calvin Cycle next.
Remember that ATP is the important source of all cellular energy. Light reaction occurs in the thylakoid membrane of chloroplasts. Since light reaction depends on sunlight, it only occurs in the presence of sunlight.
What is the Relationship between light and dark reactions of photosynthesis?
Chlorophyll A and B are the major types of chlorophylls involved in the light reaction. Chlorophyll A is the principal pigment-trapping light energy, and chlorophyll B is the accessory pigment, which traps light and passes to chlorophyll A.
Exited PS II takes electrons by splitting water molecules into molecular oxygen, generating high energy electrons, which are transferred through a series of electron carriers into PS I. Splitting of water at PS II is called photolysis.
What is the Relationship between light and dark reactions of photosynthesis? | Yahoo Answers
PS I also generates high energy electrons by the energy of sunlight. Light reaction is shown in figure 1. It occurs in the stroma of the chloroplast. The dark reaction occurs in two reaction mechanisms: C3 cycle and C4 cycle. C3 cycle is called Calvin cycle whereas C4 cycle is called Hatch-Stack cycle.Dark Reaction Calvin C3 Cycle
Calvin cycle occurs in three steps. During the first step, carbon dioxide is fixed into ribulose 1,5-bisphosphate, forming an unstable six carbon compound, which is then hydrolyzed into three carbon compound, 3-phosphoglycerate.
Difference between Light Reaction and Dark Reaction
The enzyme involved in the process is rubisco. Due to the catabolic imperfection of rubisco, photorespiration occurs in the presence of low carbon dioxide concentrations. During the second step, some of the 3-phosphoglycerates are reduced in order to produce hexose phosphates.
The remaining 3-phosphoglycerates are used in the recycling of ribulose 1,5-phosphate. During C4 cycle, double fixation of carbon dioxide is observed, increasing the efficiency of photosynthesis.