1. LEAF STRUCTURE & PHOTOSYNTHETIC PIGMENTS

2. Inside the Chloroplast
Thylakoids- Saclike membranes that store chlorophyll and accessory pigments.
Grana (Granum-singular)- stacks of thylakoids
Stroma is the fluid
filled space surrounding
the grana.

4. FIGURE 7-8 (part 1) Events of the light-dependent reactions occur in and near the thylakoid membranes

5. PHOTOSYNTHESIS

6. Photosynthesis- converts water and carbon dioxide into chemical energy stored in glucose
Chlorophyll
C6H12O6
6 H2O
6 O2

8. Pigments in plants
Pigments: proteins that trap light energy from the sun
EXAMPLES:
Chlorophyll : Appears green
A: Traps Red Light
B: Traps Blue Light
Accessory Pigments: Trap green/yellow
Carotene: Appears orange
Xanthophyll: Appears yellow
The least important color for photosynthesis?
GREEN!!

9. Why Autumn Leaves Turn Color
Both chlorophylls and carotenoids are present in leaves
Chlorophyll breaks down before carotenoids in dying autumn leaves revealing yellow colors
Red fall colors (anthocyanin pigments) are synthesized by some autumn leaves, producing red colors

10. FIGURE 7-6 Loss of chlorophyll reveals yellow carotenoids

11. FIGURE 7-2 An overview of photosynthetic structures
(a) Photosynthesis occurs primarily in the leaves of land plants. (b) A section of a leaf, showing mesophyll cells where chloroplasts are concentrated and the waterproof cuticle that coats the leaf on both surfaces. (c) A mesophyll cell packed with green chloroplasts. (d) A single chloroplast, showing the stroma and thylakoids where photosynthesis occurs.

12. FIGURE 7-2b An overview of photosynthetic structures
(b) A section of a leaf, showing mesophyll cells where chloroplasts are concentrated and the waterproof cuticle that coats the leaf on both surfaces.

13. FIGURE 7-2c An overview of photosynthetic structures
(c) A mesophyll cell packed with green chloroplasts.

15. Two Stages of Photosynthesis
1st stage: Light Reactions (Light dependent)- occurs in the thylakoids.
2nd stage: Calvin Cycle (Light Independent)- occurs in the stroma

16. Two Sets of Chemical Reactions
Photosynthesis involves two primary sets of reactions: light-dependent reactions and Calvin Cycle (light-independent reactions).
Calvin cycle 
Remind students that photosynthesis involves both light-dependent and light-independent reactions.
Ask: What do the light-dependent reactions produce?
Answer: Oxygen.
Click to highlight.
Ask: What is converted in the process?
Answer: ADP and NADP+ are converted into the energy carriers ATP and NADPH.

17. LIGHT REACTIONS Photosystem II Light is absorbed by chlorophyll.
Electrons in the chlorophyll become energized
Energy from the light splits
water molecules: 2H + O2 i
Electrons from H replace chlorophyll’s electrons that were energized.
ATP is made from ETC
Photosystem I
Light re-energizes chlorophyll electrons
Energy from ETC attaches the H+ ions to NADP+ (e- acceptor) to form NADPH.
PRODUCTS:
ATP, NADPH move to next step (calvin cycle)
6 O2 released via stomata

18. FIGURE 7-7 The light-dependent reactions of photosynthesis
(1) Light is absorbed by photosystem II, and the energy is passed to electrons in the reaction-center chlorophyll molecules. (2) Energized electrons leave the reaction center. (3) The electrons move into the adjacent electron transport chain. (4) The chain passes the electrons along, and some of their energy is used to drive ATP synthesis by chemiosmosis. Energy-depleted electrons replace those lost by photosystem I. (5) Light strikes photosystem I, and the energy is passed to electrons in the reaction-center chlorophyll molecules. (6) Energized electrons leave the reaction center. (7) The electrons move into the electron transport chain. (8) The energetic electrons from photosystem I are captured in molecules of NADPH. (9) The electrons lost from the reaction center of photosystem II are replaced by electrons obtained from splitting water, a reaction that also releases oxygen, and H+ used to form NADPH.

19. Light Reactions Overview:
1. Light energy is absorbed in the THYLAKOID.
2. Water is split apart 2H and O2
3. CO2 is NOT involved
4. Reactants: chlorophyll a & b, accessory
pigments, light energy, water, and
NADP
5. Products: O2 , ATP, NADPH

21. Products of Light Reactions
6 O2 maybe used by plant for cellular respiration or released into the air via stoma
NADPH and ATP are created. These move to the second step of photosynthesis- Calvin Cycle

22. Let’s Review Again 1. Where do the Light Reactions occur?
Why do they occur here?
What is the main event of the L.R.?
What are the final products of L.R.?

23. FIGURE 7-7 The light-dependent reactions of photosynthesis
(1) Light is absorbed by photosystem II, and the energy is passed to electrons in the reaction-center chlorophyll molecules. (2) Energized electrons leave the reaction center. (3) The electrons move into the adjacent electron transport chain. (4) The chain passes the electrons along, and some of their energy is used to drive ATP synthesis by chemiosmosis. Energy-depleted electrons replace those lost by photosystem I. (5) Light strikes photosystem I, and the energy is passed to electrons in the reaction-center chlorophyll molecules. (6) Energized electrons leave the reaction center. (7) The electrons move into the electron transport chain. (8) The energetic electrons from photosystem I are captured in molecules of NADPH. (9) The electrons lost from the reaction center of photosystem II are replaced by electrons obtained from splitting water, a reaction that also releases oxygen, and H+ used to form NADPH.

24. The Calvin Cycle (C3) Cycle
NO LIGHT IS USED
Occurs in the STROMA.
6 CO2 used to synthesize 1 glucose (C6H12O6)
Carbon dioxide is captured and linked to ribulose bisphosphate (RuBP)
ATP and NADPH from light dependent reactions used to power this step.

25. CALVIN CYCLE
C6H12O6

27. Products of the Calvin Cycle
C6H12O6
6 RUBP
ADP + Pi
NADP+

28. Summary of Photosynthesis

29. FIGURE 7-4 Relationship between the light-dependent and light-independent reactions

30. 6 H2O
6 CO2
C6H12O6
6 O2

32. Factors that Affect Photosynthesis
1. Amount of water
2. Temperatures
3. Light Intensity
4. Amount of CO2