Answer to question 1
The correct answer would be Light independent reactions require the energy gathered in the thylakoids.
Photosynthesis can divided into two sub-processes or reactions:
Light-dependent reaction: It converts solar energy into chemical energy that is, ATP (adenosine triphosphate) and NADPH with the help of photolysisis of water. It takes place in thyllakoid membrane of the chloroplast.
Light-independent reaction: It fixes carbon obtained from carbon dioxide into the food or glucose with the help of enzyme RuBisCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase).
It takes place in the stroma of the chloroplast and does not require the involvement of light however, it requires the products (ATP and NADPH) of the light reaction.
Fixation of 1 molecule of glucose requires 6 molecules of carbon dioxide, 9 molecules of ATP and 6 molecules of NADPH.
So, darkness indirectly affects the light-independent reaction.
Answer to question 2
It seems weird that the amount of light would affect the light independent reactions of photosynthesis, doesn’t it? The reactions are literally described as light independent, yet they can, indeed, be slowed by the absence of light.
There are two main sets of reactions in photosynthesis: light dependent and light independent. The light dependent reactions are the first part of photosynthesis. These reactions harness light energy and turn it into chemical energy in the form of ATP and NADPH. Both of these molecules can be thought of as batteries that help move energy from one area to another. These batteries will then be used in the light independent reactions.
If a plant is in darkness for too long, there simply won’t be enough of these batteries charged and ready to use in the light independent reactions.
The light independent reactions use the stored energy generated in the light dependent reactions to fix carbon dioxide. When carbon dioxide is fixed, it gets turned into a molecule the cell can use. In the case of the light independent reactions of photosynthesis, carbon dioxide is fixed into glucose, or sugar.
Answer to question 3