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Photosynthesis - Coggle Diagram
Photosynthesis
1. Light Reactions
-Light-dependent reactions.
-Requires photons from sunlight, photons, and H2O.
-Produces ATP and NADPH to be used in the Dark Reactions.
-Occurs in the thylakoid membrane in the chloroplast.
2. Dark Reactions
- Also known as the Calvin Cycle or Light Independent Reactions
- Occurs in the stroma (space within the chloroplast).
Phase I: Carbon Fixation
- A 5 carbon molecule, RuBP is bind with CO2 from the atmosphere, using the enzyme RubisCO.
- This 6-carbon molecule is unstable so it breaks into two 3-carbon phosphoglycerates (PGAs).
- Phase II: PGA Reduction
- 2 ATPs from the light reactions dephosphorylates into 2 ADPs. The two phosphate groups from this reaction are used to create 2 bi-phosphoglycerates.
- 2 NADPH --> 2 NADP+
- 2 NADPH reduces bi-phosphoglycerates with the electrons that are taken away to form NADP+ and 12 phosphoglyceraldehydes.
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A series of proteins within the thylakoid membrane are responsible for the Light Reactions.
1. Photons from the sunlight go through the first protein, Photo System II.
(It also enters PSI as well).
- The usage of protons in the light reactions to create ATP is called Photophosphorylation.
2. The photons excite the electrons in the chlorophyll molecules and the electrons enter into a high-energy state.
3. The electrons travel through the electron transport chain to the last transport protein: Photosystem I.
There, the final electron acceptor, NADH, reduces and accepts the electrons. NADP+ --> NADH
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- H2O (Water) from the environment is oxidized in PSII, losing electrons, to form O2 and H+. - Oxygen gets released as a by-product.
- The electrons from this oxidation reaction also get excited and travel through the transport chain.
- The hydrogen photons accumulate in the lumen of the thylakoid.
- In order for the H+ to go from a high-energy space (lumen) to a low-energy space (stroma), an ATP synthase protein is used. This energy from that action allows ADP and a phosphate group to bind and become ATP.