1. How Plants Convert Solar Energy into Chemical Energy (Glucose)
Photosynthesis
How Plants Convert Solar Energy into Chemical Energy (Glucose)

2. Leaves are organs that carry out photosynthesis.
Go through the activity: E-Life 8.1 p.2-5

3. Leaf Cross-section:

4. Lilac Leaf Cross Section

5. Plant Cell

6. The Inside of a Chloroplast
Thylakoid space
Stroma
Outer membrane
Inner membrane
Grana
Thylakoid

7. Outer membrane
Protective covering allows only small molecules to diffuse through (semi-permeable)

8. Inner membrane
Forms border for stroma and regulates passage of materials in and out of the chloroplasts

9. Stroma
Dense fluid within the chloroplast that lies inside the membranes, it is the site of conversion of CO2 to Sugar

10. Grana
Dense layered stacks of thylakoid sacs

11. Thylakoid membrane
Internal membrane system consisting of a flattened sac

12. Thylakoid Space
Serves as site that converts light energy to chemical energy inside the thylakoid membrane

13. The Chemical Formula of Photosynthesis
6CO2 + 6H2O C6H12O6 + 6O2
Carbon Water Glucose Oxygen
dioxide

14. Photosynthesis consists of Two major Reactions

15. Light Reactions Overview
H2O O2
Occurs on thylakoid membrane
Light energy is absorbed by chlorophyll found in Photosystems I & II
Water is split releasing O2
NADPH & ATP are formed after series of reactions

16. Light Dependent Reactions take place on the membrane surface of the Thylakoid
Hon LR
Aca LR

17. Step 1: Photosystem II (PS II)
The pigments in PS II absorb light energy and excites electrons which increases their energy level.
The electrons travel to the electron transport chain.
The electrons come from broken up water molecules that create 2 electrons, 2 H+ and 1 oxygen.
The oxygen is released so we can breathe it and the H+ are released into the thylakoid membrane

18. Step 2: Electron Transport Chain (ETC)
The excited high energy electrons from PS II travel through the electron transport chain to reach PS I
The electron’s energy is used by the molecules in the ETC to transport H+ ions from the Stroma to the inner thylakoid space.

19. Step 3: Photosystem I (PS I)
The pigments in PS I use light to reenergize the electrons
A molecule NADP+ picks up the high energy electrons and H+ ions to then become NADPH

20. Step 4: Hydrogen Ion Movement
During step 3 when the electrons leave the ETC to go to the NADP+, H+ ions are pumped across the thylakoid membrane.
As this continues, the Thylakoid spaces fill up with H+ and becomes Positively charged while the thylakoid membrane is negatively charged.
This charge difference provides the energy to make ATP

21. Step 5: ATP formation
A protein called ATP synthase on the thylakoid membrane allows H+ ions to pass through the membrane since they cannot cross on their own.
As H+ passes through, the protein rotates like a turbine building up energy, this energy allows the ADP and a Phosphate group join together to produce ATP

22. Overview of Light reactions
Reactants (what goes in): Water, ADP, and NADP+
Products (what comes out): Oxygen, ATP, and NADPH
ATP and NADPH move on to the Calvin Cycle

23. Light Reactions Children’s Story
Compose a children’s story about the travels of an electron through the light reactions.
Be sure to represent all the elements of the light reactions in your story.
Illustrate a scene from your story which will best represent the activity during the light reactions.
Attach your story to your illustration.

24. The Calvin Cycle 1. Occurs in the Stroma 2
The Calvin Cycle 1. Occurs in the Stroma 2. Uses 6CO2 from the atmosphere 3. Energy is provided from ATP and NADPH (from Light Reactions) 4. After 2 cycles, glucose is made.

26. Step 1: Carbon Fixation
6 carbon dioxide (CO2) molecules enter the cycle from the atmosphere.
CO2 combines with 6, 5-carbon molecules and produces 12, 3-carbon molecules

27. Step 2: Reduction
Energy from ATP and high energy electrons NADPH are used to convert the 12 3-carbon molecules into higher energy forms.

28. Step 3: Release of one G3P
Two of the 12 3-Carbon molecules leave the cycle to produce things like sugars, lipids, amino acids, and other compounds needed for the plants metabolism and growth.

29. Step 4: Regeneration of RuBP
The remaining ten 3-carbons are converted back into six 5-carbon molecules.
These molecules will combine with 6 new CO2 molecules to begin the next cycle.
Remember: the glucose is not made until after the second cycle!

31. Photosynthesis Essential Questions
Name the two most important parts of a chloroplast. Which parts of photosynthesis occurs in each structure?
What are the reactants and products of the Light Reactions? The Calvin Cycle?
Explain how the Calvin Cycle is indirectly dependent on light.
Explain how ATP synthase is a protein channel and an enzyme.

32. PhotoFinish Alterations
Fill 2 beakers with 80 mL sodium bicarbonate solution
Once air spaces are vacuumed, pour syringe solution and leaf disks into each beakers (10 disks each).
Make sure both sets are ready to start at the same time.
May use stop watch feature on phone.

33. PhotoFinish Cleanup
Discard solution down drain—Do NOT let leaf disks down drain!!
Discard used spinach and disks in trash
Rinse out beakers; return to side
Separate syringes, clean out hole punches; return to side
Unplug lamp & dry off area