Q.Light and dark reactions are interdependant – Explain.
You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.
Start your 14-day free trial to unlock the full solution →The light reaction supplies ATP and NADPH2 that the dark reaction needs to fix CO2, while the dark reaction regenerates the ADP and NADP+ that the light reaction needs to keep producing them — so neither can continue...
Light reaction supplies energy (ATP/NADPH2) to the dark reaction; the dark reaction regenerates ADP/NADP+ for the light reaction.
The light reaction of photosynthesis, occurring in the thylakoid membranes, captures light energy to split water (photolysis, releasing O2) and to generate two energy-rich products: ATP (via photophosphorylation) and NADPH2 (via reduction of NADP+ through the electron transport chain). However, the light reaction has no way of using these products itself — it simply keeps producing them as long as light and its raw materials (ADP, NADP+, water) are available. The dark reaction (Calvin cycle), occurring in the stroma, uses this ATP and NADPH2 to reduce fixed CO2 step by step into carbohydrate, but it cannot proceed at all without a continuous supply of ATP and NADPH2 — and it has no independent way to generate them, since it does not itself use light. At the same time, the dark reaction regenerates the ADP and NADP+ that are consumed, feeding the …
Unlock everything free for 14 days
- Full step-by-step solutions
- Concept-first explanations
- Methods, shortcuts & mistakes
- PYQ mapping + timed mock tests
Full access for 14 days. No credit card required.