๐ฟ DAT Photosynthesis Made Simple: Light Reactions and Calvin Cycle Explained
Photosynthesis is a cornerstone of cellular energy transformation, essential for plant survival and food production.
On the DAT, expect questions that test your understanding of inputs, outputs, and chloroplast structure.
In this blog, weโll break down the light reactions, Calvin cycle, and the flow of energy through ATP and NADPH.
๐ Where It Happens: The Chloroplast
Thylakoid Membranes: Site of light reactions
Stroma: Site of the Calvin cycle
Contains chlorophyll, pigment responsible for light absorption
โก Light-Dependent Reactions (Thylakoids)
Component | Function |
---|---|
Light Energy | Excites electrons in Photosystem II |
HโO | Split to release electrons, Hโบ, and Oโ (photolysis) |
Photosystem II | Passes electrons through ETC to generate ATP |
Photosystem I | Re-excites electrons to reduce NADPโบ โ NADPH |
Products | ATP, NADPH, and Oโ |
๐ DAT Tip: The Oโ you breathe comes from water, not COโ!
๐ฑ Light-Independent Reactions: The Calvin Cycle (Stroma)
Input: ATP, NADPH, COโ
Main Enzyme: RuBisCO
Output: Glucose (or G3P)
Does not require light directly, but depends on products of light reactions
Calvin Cycle Phases:
Carbon Fixation
Reduction (G3P formation)
Regeneration of RuBP
๐ง Photosynthesis Equation (You Must Know)
๐งช DAT Question Examples
โWhich molecule is the final electron acceptor in the light reactions?โ
โWhat enzyme fixes carbon dioxide?โ
โWhere is ATP used during photosynthesis?โ
๐ฏ Call to Action
Ready to master every pathway?
KOTC can help you:
Diagram light and dark reactions
Drill enzyme names like RuBisCO and ATP synthase
Compete in multiplayer quizzes on chloroplast structure
Use adaptive flashcards to retain photosystem steps
โ Summary
Photosynthesis occurs in the chloroplast and involves:
Light reactions (in thylakoids) โ ATP + NADPH
Calvin cycle (in stroma) โ glucose
Know what goes in, what comes out, and where
Understand energy flow and molecule conversions
Frequently Asked Questions (FAQs)
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Practice mindfulness techniques, take practice exams under realistic conditions, and maintain a balanced lifestyle.
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