Quote

Success is how high you bounce when you hit bottom

Difference between Light and Dark Reactions in Photosynthesis

Photosynthesis is a complex process of synthesis of organic food materials. It is a oxidation - reduction process. Here water is oxidised and carbon dioxide is reduced to carbohydrates. Photosynthesis takes place in two steps: i) light reaction ii) dark reaction
Light Reaction is the first stage in photosynthesis where water is broken in the chlorophyll molecule into H+ ions and OH- ions in the presence of light resulting in the formation of assimilatory powers such as NADPH2 and ATP . It occurs in the grana of chloroplast.
Light and Dark Reaction
Dark Reaction is the second step in the mechanism of photosynthesis. The chemical processes of photosynthesis occurring independent of light is called dark reaction. It takes place in the stroma of the chloroplast. The Dark reaction of photosynthesis is purely enzymatic and it is slower than the light reaction. In dark reactions, two types of cyclic reaction occur. They are Calvin cycle or C3 Cycle and Hatch Slack Cycle or C4 cycle.
In dark reaction, sugars are synthesised from CO2. The energy poor carbon dioxide is fixed to energy rich carbohydrates using the energy rich compound ATP and the assimilatory power NADPH2 of light reaction. This process is called carbon fixation.
Blackman first demonstrated the existence of dark reaction .Hence it is known as Blackman’s reaction.
Light Reaction vs Dark Reaction
Light Reaction
Dark Reaction
Occurs : Grana of the chloroplasts. Occurs: Stroma of the chloroplast
It is a light dependent process Involves two photosystems: PS I and PS II This process does not require light. No photosystem is required.
Photolysis of water takes place and oxygen is liberated. Photolysis of water does not take place. Carbon dioxide is absorbed.
ATP and NADPH is produced and they are used to drive the dark reaction. Glucose is produced. Reduced NADP is oxidised.

41 comments:

  1. very very helpful

    ReplyDelete
  2. i need something more

    ReplyDelete
  3. Comparing is where?

    ReplyDelete
  4. Thanks you! :)

    ReplyDelete
  5. Pretty helpful, thanks alot.

    ReplyDelete
  6. all backwards

    ReplyDelete
  7. blackman's reaction...lol

    ReplyDelete
  8. greatly helpful. direct answers, no need to search for more!!!!!!!!!!!!!!!!!!!!!!





    ReplyDelete
  9. Thanks ! Was so helpful !! :D

    ReplyDelete
  10. Very useful for my project!
    -ABHIJITH.D

    ReplyDelete
  11. Really very helpful.
    Thanks A Ton. ��

    ReplyDelete
  12. Thanks a lot. My students learnt from this. Made my lesson easy.

    ReplyDelete
  13. It's Fucking Awsome Yeeeaaaah!!!!!!!!!!!!!

    ReplyDelete
  14. it was really helpful..keep it up,thumbs up!

    ReplyDelete
  15. It was very helpful to me. Thank you. :)

    ReplyDelete
  16. please explain what light and dark reaction are

    ReplyDelete
  17. Hopefully this will help me in my exam

    ReplyDelete
  18. It was good.woieeyowie

    ReplyDelete
  19. Thnks a lot ..... . . but fr unknowns u shud explain wid details

    ReplyDelete
  20. great....thanks

    ReplyDelete
  21. I was unknown too.but it is pretty good for me.thanx alot.

    ReplyDelete
  22. Not bad......it helped....

    ReplyDelete
  23. It is very useful information about dark and light

    ReplyDelete
  24. Thnxx... Helped a lot

    ReplyDelete
  25. Nice and to the point . thanks

    ReplyDelete
  26. It made me do my exam well, biology exam

    ReplyDelete
  27. Thank you so much it's very my helpful
    - vaishu 😍😍😍

    ReplyDelete
  28. thanks better than the other sites i checked

    ReplyDelete

We Love to hear from U :) Leave us a Comment to improve this site
Thanks for Visiting.....