What is the relationship between the light and dark reactions of photosynthesis?

Question

My main concern is why are the dark reactions (those that produce hexose) needed? As far as I understand, the sole purpose of photosynthesis is to synthesize carbohydrates, which are only used for energy storage. So, why don’t plants store energy directly as ATP (by photophosphorylation) and not as carbohydrates? (Of course, that would be too bad for other creatures.) Elaborating my question: 1. Plants use chlorophyll to convert light energy into chemical energy of ATP and NADPH by photophosphorylation and chemiosmosis. 2. Then plants use the ATP and NADPH to synthesize glucose by the Calvin cycle. So, what is the need of step 2? Why don‘t plants just use that ATP and NADPH for their metabolism?

Answer 1

Plants produce carbohydrates to form cellulose. From the Internet: Cellulose is a very important polysaccharide because it is the most abundant organic compound on Earth. Cellulose is a major component of tough cell walls that surround plant cells, and it's what makes plant stems, leaves, and branches so strong.

So, your assertion : "As far as I understand, the sole purpose of photosynthesis is to synthesize carbohydrates, which are only used for energy storage." is incorrect.