2. Chloroplast
An organelles that specializes in photosynthesis in plants and many protists. Plant chloroplast have two outer membranes , and are filled with a semifluid matrix call the stroma.
Stroma contains the chloroplast’s DNA, some ribosomes, and an inner, much-folded thylakoid membrane. The folds of a thylakoid membrane typically forms stacks of disks that are connected by channels. The space inside all of the disks and channels is a single, continuous compartments.
Many thylakoids together make a granum.

4. Chlorophyll
A molecule in chloroplasts that absorbs some of the energy in visible light. Chlorophyll α and β absorbs mostly red and blue wavelengths (λ) of visible light. Neither type absorbs much green light.
As a result, the green color of plants comes from the reflection of the light’s wavelengths by the chlorophyll.

5. Only light between 380 – 750 nm drive photosynthesis.
Electromagnetic Spectrum

6. Photosynthesis
A process that captures energy from sunlight to make sugar that store chemical energy. Photosynthesis uses energy captured from the sunlight to change carbon dioxide and water into oxygen and sugars (glucose).
Sunlight is absorbed during the light-dependent reactions and sugars are made during the light-independent reactions.

7. Photosynthesis
Photosynthesis is actually a series of many reactions that occur in two stages.
Light-dependent
Light-independent

8. 6CO2 + 6H2O + Light C6H12O6 + 6O2

9. Light-dependent Reaction
First stage; capture energy from sunlight. These reactions take place in the thylakoid membrane. Water and sunlight are need for this process.
Chlorophyll absorbs energy from sunlight. The energy is transferred along the membrane. Water molecules are broken down. Oxygen molecules are released.
Energy carried along the membrane is transferred to molecules that carry energy, ATP and NADPH.

10. Light-Dependent Reactions
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen. The light-dependent reactions take place within the thylakoid membranes of chloroplasts.
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Photosynthesis begins when pigments in photosystem II absorb light, increasing their energy level.
Photosystem II
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen. The light-dependent reactions take place within the thylakoid membranes of chloroplasts.
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These high-energy electrons are passed on to the electron transport chain.
Photosystem II
Electron carriers
High-energy electron
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Enzymes on the thylakoid membrane break water molecules into:
Photosystem II
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
Electron carriers
High-energy electron
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hydrogen ions
oxygen atoms
energized electrons
Photosystem II
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
Electron carriers
High-energy electron
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The energized electrons from water replace the high-energy electrons that chlorophyll lost to the electron transport chain.
Photosystem II
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
High-energy electron
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As plants remove electrons from water, oxygen is left behind and is released into the air.
Photosystem II
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen. The light-dependent reactions take place within the thylakoid membranes of chloroplasts.
High-energy electron
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The hydrogen ions left behind when water is broken apart are released inside the thylakoid membrane.
Photosystem II
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
High-energy electron
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Energy from the electrons is used to transport H+ ions from the stroma into the inner thylakoid space.
Photosystem II
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
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High-energy electrons move through the electron transport chain from photosystem II to photosystem I.
Photosystem II
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
Photosystem I
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Pigments in photosystem I use energy from light to re-energize the electrons.
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
Photosystem I
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NADP+ then picks up these high-energy electrons, along with H+ ions, and becomes NADPH.
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
2 NADP+ 2 2
NADPH
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As electrons are passed from chlorophyll to NADP+, more H+ ions are pumped across the membrane.
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
2 NADP+ 2 2
NADPH
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Soon, the inside of the membrane fills up with positively charged hydrogen ions, which makes the outside of the membrane negatively charged.
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
2 NADP+ 2 2
NADPH
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The difference in charges across the membrane provides the energy to make ATP
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
2 NADP+ 2 2
NADPH
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H+ ions cannot cross the membrane directly.
ATP synthase
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
2 NADP+ 2 2
NADPH
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The cell membrane contains a protein called ATP synthase that allows H+ ions to pass through it
ATP synthase
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
2 NADP+ 2 2
NADPH
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As H+ ions pass through ATP synthase, the protein rotates.
ATP synthase
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
2 NADP+ 2 2
NADPH
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As it rotates, ATP synthase binds ADP and a phosphate group together to produce ATP.
ATP synthase
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
ADP
2 NADP+ 2 2
NADPH
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Because of this system, light-dependent electron transport produces not only high-energy electrons but ATP as well.
ATP synthase
+ O2
2H2O
The light-dependent reactions use energy from sunlight to produce ATP, NADPH, and oxygen.
ADP
2 NADP+ 2 2
NADPH
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31. Light-independent Reaction/Calvin Cycle
Second stage; uses energy created in the light-dependent reaction to make sugars. This reaction takes place in the stroma of the chloroplast. Carbon Dioxide is needed during this stage of photosynthesis.
CO2 is added to a cycle of chemical reactions to build larger molecules. Energy from the light-dependent reaction is used.
A carbohydrate (C6H12O6) molecule is made, which stores energy that was captured from sunlight.

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Six carbon dioxide molecules enter the cycle from the atmosphere and combine with six 5-carbon molecules.
CO2 Enters the Cycle
The Calvin cycle uses ATP and NADPH to produce high-energy sugars.
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The result is twelve 3-carbon molecules, which are then converted into higher-energy forms.
The Calvin cycle uses ATP and NADPH to produce high-energy sugars.
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The energy for this conversion comes from ATP and high-energy electrons from NADPH.
Energy Input 12
12 ADP 12
NADPH
The Calvin cycle uses ATP and NADPH to produce high-energy sugars.
12 NADP+
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Two of twelve 3-carbon molecules are removed from the cycle.
Energy Input 12
12 ADP 12
NADPH
The Calvin cycle uses ATP and NADPH to produce high-energy sugars.
12 NADP+
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36. The molecules are used to produce sugars, lipids, amino acids and other compounds.12
12 ADP 12
NADPH
The Calvin cycle uses ATP and NADPH to produce high-energy sugars.
12 NADP+
6-Carbon sugar produced
Sugars and other compounds
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37. The 10 remaining 3-carbon molecules are converted back into six 5-carbon molecules, which are used to begin the next cycle. 12
12 ADP
6 ADP 12
NADPH 6
The Calvin cycle uses ATP and NADPH to produce high-energy sugars.
12 NADP+
5-Carbon Molecules Regenerated
Sugars and other compounds
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38. The two sets of photosynthetic reactions work together.
The light-dependent reactions trap sunlight energy in chemical form.
The light-independent reactions use that chemical energy to produce stable, high-energy sugars from carbon dioxide and the hydrogen from water.