TREE PHYSIOLOGY
PHOTOSYNTHESIS
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
I
|
|
II
|
|
I and II
|
|
None of the above
|
Detailed explanation-1: -The light-dependent reactions use light energy to make two molecules needed for the next stage of photosynthesis: the energy storage molecule ATP and the reduced electron carrier NADPH. In plants, the light reactions take place in the thylakoid membranes of organelles called chloroplasts.
Detailed explanation-2: -ATP and NADPH produced by the light-dependent reactions of the photosystems are used by the Calvin cycle in the stroma of the chloroplast. Molecules of CO2 gas are fixed into molecules of 3-phosphoglycerate in a reaction catalyzed by the enzyme Rubisco.
Detailed explanation-3: -Photosynthesis takes place in two distinct stages. In the light reactions, energy from sunlight drives the synthesis of ATP and NADPH, coupled to the formation of O2 from H2O. In the dark reactions, so named because they do not require sunlight, the ATP and NADPH produced by the light reactions drive glucose synthesis.
Detailed explanation-4: -For ATP, energy is released with the loss of the terminal phosphate atom, converting it into ADP; for NADPH, both energy and a hydrogen atom are lost, converting it into NADP+. Both of these molecules return to the nearby light-dependent reactions to be reused and re-energized.