question about calvin cycle

[LaughingGas]

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Is calvin cycle light dependent or independent? I'm using barrons and quoting " The Calvin cycle is the main business of the light-independent reactions...... The Calvin cycle, like the light-dependent reactions, occurs only in the light".

 

[jhmcknight]

From my understanding, the light-dependent is the process in which ATP and NADPH are generated (photophosphorylation). These components are used in the light-independent reaction to fixate carbon (in the form of CO2) known as the Calvin-Benson cycle, to produce G3P...eventually glucose. This process occurs in the both the light and the dark but is called the "dark reaction" because it doesn't directly require light. The Calvin Cycle itself is light-independent, but it needs NADPH and ATP produced by the light-dependent reaction.

Hope that makes sense...

 

[NDPitch]

From my understanding, the light-dependent is the process in which ATP and NADPH are generated (photophosphorylation). These components are used in the light-independent reaction to fixate carbon (in the form of CO2) known as the Calvin-Benson cycle, to produce G3P...eventually glucose. This process occurs in the both the light and the dark but is called the "dark reaction" because it doesn't directly require light. The Calvin Cycle itself is light-independent, but it needs NADPH and ATP produced by the light-dependent reaction.

Hope that makes sense...

Both right and wrong! This would be a great DAT question. The trap is to think that the Calvin cycle does not need light to occur, because it's called the "dark reactions". In reality, if there was not light, the cycle couldn't happen because there would be no ATP and NADPH. The Calvin cycle became known as light independent or "dark" because light is not a "reactant" so to speak, BUT the reactants that it does use are directly dependent on the presence of light!

 

[LaughingGas]

Thank you both. It made it really clear now 😀😀

 

[jhmcknight]

Both right and wrong! This would be a great DAT question. The trap is to think that the Calvin cycle does not need light to occur, because it's called the "dark reactions". In reality, if there was not light, the cycle couldn't happen because there would be no ATP and NADPH. The Calvin cycle became known as light independent or "dark" because light is not a "reactant" so to speak, BUT the reactants that it does use are directly dependent on the presence of light!

Right, thats why I said it doesn't directly need light. However, the whole "system" needs light to generate ATP and NADPH to bring to the "dark reaction".

You get the idea. Nature is crazy (cool).

 

[BRZ24]

Right, thats why I said it doesn't directly need light. However, the whole "system" needs light to generate ATP and NADPH to bring to the "dark reaction".

You get the idea. Nature is crazy (cool).

Calvin cycle does NOT directly use light but light has to be present for photophosphorylation to happen to produce NADPH and ATP for calvin cycle.

 

[SGStudent]

This really helped me.. check it out: http://www.khanacademy.org/science/biology/v/photosynthesis---calvin-cycle