1. Section 2: Photosynthesis
Light energy is trapped and converted into chemical energy during photosynthesis.

2. Essential Questions What are the two phases of photosynthesis?
What is the function of a chloroplast during the light reactions?
How can electron transport be described and diagramed?
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Photosynthesis

3. Day 1 Vocabulary Review New carbohydrate thylakoid granum Stroma
Electron transport molecules
pigment
NADP+
Photosynthesis
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4. Carbohydrate

5. Overview of Photosynthesis
Most autotrophs make organic compounds using photosynthesis.
Photosynthesis is the process of converting light energy into chemical energy.
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Photosynthesis

6. Overview of Photosynthesis
Photosynthesis occurs in two phases.
In the light-dependent phase, light energy is converted into chemical energy.
In the light-independent phase, chemical energy used to synthesize glucose.
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Photosynthesis

7. Phase One: Light Reactions
The absorption of light is the first step in photosynthesis.
Once light energy is captured, it can be stored as ATP or NAPDH.
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Photosynthesis

8. Phase One: Light Reactions
Chloroplasts
Organelles that capture light energy
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Photosynthesis

9. Phase One: Light Reactions
Chloroplasts
Contain two main compartments:
Thylakoids: flattened saclike membranes
Stacks of thylakoids are called grana.
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Photosynthesis

10. Phase One: Light Reactions
Chloroplasts
Contain two main compartments:
The fluid filled space outside the grana called the stroma.
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Photosynthesis

11. Phase One: Light Reactions
Pigments
Light-absorbing colored molecules called pigments are found in the thylakoid membranes.
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Photosynthesis

12. Phase One: Light Reactions
Pigments
Different pigments absorb specific wavelengths of light.
Most common pigment in plants is chlorophyll.
Plants also have accessory pigments.
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Photosynthesis

13. Phase One: Light Reactions
Electron transport
Takes place across the thylakoid membrane
This includes a large number of electron transporting molecules and two types of protein complexes called photosystems.
Photosystems house the light-capturing pigments.
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Photosynthesis

14. Phase One: Light Reactions
Electron transport
Light energy excites electrons in photosystem II.
This light energy causes a water molecule to split – releasing an electron into the electron transport system, a hydrogen ion (H+ or proton) into the thylakoid space, and oxygen as a waste product.
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Photosynthesis

15. Phase One: Light Reactions
Electron transport
The activated electrons move from photosystem II to an acceptor molecule in the thylakoid membrane.
The electron acceptor molecule transfers the electrons along a series of electron carriers to photosystem I.
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Photosynthesis

16. Phase One: Light Reactions
Electron transport
In the presence of light, photosystem I transfers the electrons to a protein called ferrodoxin.
Ferrodoxin transfers the electrons to the carrier molecule NADP+, forming the energy storage molecule NADPH.
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Photosynthesis

17. Phase One: Light Reactions
Electron transport
ATP is produced in conjunction with the electron transport system through chemiosmosis.
ATP is produced through the flow of electrons down a concentration gradient.
The breakdown of water provides the necessary protons for ATP synthesis.
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Photosynthesis

18. Review Essential Questions Vocabulary
What are the two phases of photosynthesis?
What is the function of a chloroplast during the light reactions?
Vocabulary
thylakoid
granum
stroma
Pigment
NADP+
Photosynthesis
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19. Quiz 5 What are the two phases of photosynthesis?
What is the function of a chloroplast during the light reactions?
How can electron transport be described and diagramed?
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Photosynthesis

20. Day 2 Essential Questions
What role does CO2 play in the Calvin Cycle?
What is the end result of the Calvin Cycle?
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Photosynthesis

21. Day 2 Vocabulary Review New Electron Transport Chain Calvin cycle
thylakoid
granum
stroma
pigment
NADP+
New
Calvin cycle
rubisco
Photosynthesis
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22. Review: Electron Transport Chain
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Photosynthesis

23. Phase Two: The Calvin Cycle
In the second phase of photosynthesis, called the Calvin cycle, energy is stored in organic molecules such as glucose.
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Photosynthesis

24. Phase Two: The Calvin Cycle
The first step of the Calvin cycle is called carbon fixation.
CO2 molecules combine with 5-carbon molecules to form 3- phosphoglycerate (3-PGA)
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Photosynthesis

25. Phase Two: The Calvin Cycle
In the second step, chemical energy stored in ATP and NADPH is transferred to the 3-PGA to form glyceraldehyde 3-phospate (G3P).
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Photosynthesis

26. Phase Two: The Calvin Cycle
In the third step, some G3P molecules leave the cycle to be used for the production of glucose and other organic compounds.
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Photosynthesis

27. Phase Two: The Calvin Cycle
In the fourth and final step, an enzyme called rubisco converts the remaining G3P molecules into 5-carbon molecules called ribulose 1,5-bisphospates (RuBP).
These molecules combine with new CO2 and continue the cycle.
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Photosynthesis

28. The Calvin Cycle
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Photosynthesis

29. Alternative Pathways CAM plants
Crassulacean acid metabolism (CAM) is found in desert plants.
Collect CO2 at night and store it in organic compounds
During the day, release CO2 from organic compounds for the light-dependent cycle of photosynthesis
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Photosynthesis

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Photosynthesis

31. Photosynthesis Review
Sunlight hits receptors in the thylakoid membrane
This with the combination of H2O and starts the electron transport chain

32. Photosynthesis Review
The electron transport chain sets up the production of ATP

33. Photosynthesis Overview

34. Review Essential Questions Vocabulary
What role does CO2 play in the Calvin Cycle?
What is the end result of the Calvin Cycle?
Vocabulary
thylakoid
granum
stroma
pigment
NADP+
Calvin cycle
rubisco
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Photosynthesis