The stroma is the space within the inner membrane.

It also contains thylakoids, which stacked together are called a granum or grana.

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6CO₂ + 12H₂O + light energy = 6C₆H₁₂O₆ + 6H₂O + 6O₂

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Photosynthesis is a highly endergonic reaction, it requires ATP and high energy electrons.

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1. Light Reactions- Inside the thylakoid membrane.

2. Calvin Cycle- Inside the stroma.

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Chlorophyll is a pigment which absorbs light. It has a poryphin ring "head" and a hydrocarbon tail. The "head" absorbs the light.

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1. Light Harvesting Complex- 100-300 Chlorophyll with proteins.

2. Reaction Center- Special pair of chlorophyll with other proteins.

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Photosystem II- A photon of light is absorbed by the light harvesting complex (antennae) which excites the electrons and moves them to a higher energy shell. The energy (not the electrons) is transferred from antennae to antennae in this manner until reaching the special pair of chlorophyll in the reaction center. In the reaction center the special pair of chlorophyll's electron is taken by an electron acceptor and passed along an electron transport chain.

Photosystem I- Same as photosystem II, but with higher energy levels. Here the electron is not passed along an electron transport chain, it is handed off to ferredoxin.

While the photosystems are occuring, the center protein in the electron transport chain between the photosystems is pumping H⁺ from the stroma to the thylakoid space creating an electrochemical gradient. This gradient runs the ATP synthase just like in the mitochondria.

Basically, ATP and NADPH production, which are necessary for the Calvin Cycle.

1. ATP

2. NADPH

3. Oxygen is produced

4. Water is comsumed.

1. Carbon Fixation- A 5 carbon sugar (RuBP) binds with CO₂ to create a 6 carbon sugar. Rubisco catalyzes this reaction. The unstable 6C molecule is immediately broken into 2 3C sugars (3PG).

2. Reduction- ATP is used to oxidize NADPH into NADP⁺ which makes G3P (not to be confused with 3PG). 1 G3P goes off ot make glucose, the others continue in the cycle.

3. Regeneration- G3P + ATP create RuBP (starting chemical).

Stomata

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When Rubisco binds RuBP and O₂ instead of CO₂.

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Carbon fixation is separated spatially by the mesophyll and bundle-sheath cells. The enzyme PEP C binds PEP to CO₂ with a 4C sugar in the bundle-sheath cells which are CO₂ impermeable, so it can gather high concentrations of CO₂. Once the Carbon Dioxide is in the bundle-sheath cell rubisco takes over and is more likely to choose the CO₂ because there's so much.

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The plant opens its stomata at night. Carbon fixation is separated temporally. It happens at night and the CO₂ is fixed into organic acids. During the day, the plant closes its stomata and liberates the CO₂ from the acids then performs the rest of the Calvin Cycle.

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