Photosynthesis 

Light Dependent Reactions 

The light-dependent reactions of photosynthesis take place in the thylakoid membranes of chloroplasts. They use light energy to split water molecules into hydrogen and oxygen, and to produce ATP and NADPH.

  • Stage 1: Light energy is absorbed by chlorophyll molecules, which are the green pigments in chloroplasts. This energy is used to excite electrons, which are then transferred to a series of electron carriers.
  • Stage 2: 
  1. The electron carriers transfer the electrons to NADP+, which is reduced to NADPH. 
  2. The electrons also transfer protons to the stroma, which creates a proton gradient. The proton gradient is used to drive the synthesis of ATP from ADP and Pi.



The light-dependent reactions of photosynthesis are essential for the production of ATP and NADPH, which are used in the Calvin cycle to fix carbon dioxide into glucose.


Light Independent Reactions

The light-independent reactions of photosynthesis, also known as the Calvin cycle, take place in the stroma of chloroplasts. They use ATP and NADPH from the light-dependent reactions to fix carbon dioxide into glucose.
  • Stage 1 (Carbon Fixation): Carbon dioxide is fixed into a three-carbon molecule called 3-phosphoglycerate (3-PGA).
  • Stage 2 (Reduction): 3-PGA is reduced to glyceraldehyde 3-phosphate (G3P) using ATP and NADPH.
  • Stage 3 (Regeneration of RuBP): G3P is used to synthesize RuBP and other Carbodydrates.



The Calvin cycle is essential for the production of glucose, which is the primary energy source for plants and other organisms.




Comments

Post a Comment

Popular posts from this blog

Image
  LIQUORICE Biological Source Plant Part – Peeled and un peeled stolons, root and stem Scientific Name – Glycyrrhiza glabra Family – Leguminosae Morphology Odour : Characteristic   Taste : Sweet Shape : Cylindrical   Chemical Constituents *        Saponin glycoside: Glycyrrhizin and glycyrrhizin acid *        Coumarin derivatives – Umbellirerone       Chemical Tests Salkowski test   few drops of con. H 2 SO 4 + liquorice powder ¯ Reddish Brown colour liquorice contains glycyrrhizin Uses 1.       Demulcent and Expectorants 2.     
Read more
Image
Shikimate Pathway  The shikimate pathway is a metabolic pathway that synthesizes aromatic amino acids, such as phenylalanine, tyrosine, and tryptophan, and a variety of other aromatic compounds, such as quinones, flavonoids, and lignin. Stages  Stage 1: The synthesis of shikimate from phosphoenolpyruvate (PEP) and erythrose 4-phosphate. This step is catalyzed by the enzyme 3-dehydroquinate synthase (DHS).  DHS condenses PEP and erythrose 4-phosphate to form 3-dehydroquinate. 3-dehydroquinate is then reduced to shikimate by the enzyme shikimate dehydrogenase (SDH). Stage 2: The conversion of shikimate to chorismate. The key enzymes in this stage are shikimate kinase (SK), 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), chorismate synthase (CS), and chorismate mutase (CM). Stage 3: The conversion of chorismate to aromatic amino acids and other aromatic compounds. Chorismate can be converted to a variety of aromatic amino acids and other aromatic compounds, including phenylalanine,
Read more