Although the Calvin Cycle can occur without light for a while, what would happen if the plant is always in the

Question

dark? Why would the Calvin Cycle fail?

Answer 1

Please take note that the inputs in Calvin Cycle are mainly the product of metabolic pathways that occur in Light Reaction. The consumption of these reactants will fail Calvin Cycle in the dark.

Answer 2

Light "excites" (that's a chemical term) chlorophyll molecules

witch enables it to split water molecules (photolysis), releasing oxygen and hydrogen atoms.  This is a type of oxidation that produces energy necessary to make ATP.  ATP is a high energy compound needed to "drive" the "dark" reactions of the Calvin Cycle. Therefore: No light , no photolysis, no ATP, no energy for the Calvin cycle, no glucose production, eventually no plant .

This is a bit oversimplified, but basically what happens.

Answer 3

I am sorry to say that your basics are wrong !!!

1 )  Calvin Cycle is a LIGHT INDEPENDENT  reaction in which light plays NO ROLE .

Please note very well that Calvin Cycle DOES NOT require darkness.

1) In  LIGHT REACTION  or HILL REACTION  The sunlight ( Or any sufficient light ) is used to produce  ATP  and NADPH2

These two energy rich molecules can not be produced in the photosynthesis IN THE ABSENCE of a light source only because the LIGHT ENERGY  is literally trapped in this reaction .

Therefore , the title " Light Reaction " is apt or appropriate !!

2 ) Immediately , after light reaction , Calvin cycle begins in C3 plants ( which are in majority ) .

This Calvin cycle makes use of  ATP & NADPH2 produced earlier in the light reaction to synthesize glucose .

This process does not need Light ( Only because of this it is termed as Dark reaction and this has led to confusion in the minds of many !!) ; BUT at the same time it does not require Darkness!!!!

2 ) What would happen if the plant is always in the dark?

If a plant is always in the dark in it will literally die ( Leaves will turn yellow ).

The light reaction will not occur ( Forget about the dark reaction ). No photosynthesis ..

kindly click the link to learn more .

http://en.wikipedia.org/wiki/Dark_reacti...

From = A Botanist