1. 8.2 Photosynthesis
Pages

2. LEQ: How is energy, which ultimately comes from the sun, transformed into useable energy?

3. Introduction to Photosynthesis Video

4. Photosynthesis
Photosynthesis is the process of turning light energy into chemical energy!

5. Chemical Equation

6. Photosynthesis Photosynthesis occurs in TWO phases.
Light-dependent reactions
Light-independent reactions (dark reactions)

7. Remember the “reactants”…….
Carbon Dioxide (CO2)
Water (H20)
Energy (sunlight)

8. Where do the reactants come from?
CO2 (a gas) is in the atmosphere and enters the plant through small openings on the back of leaves called stomata.
The stomata is where gas exchange occurs. CO2 in; O2 out

9. Where does everything come from?
Water (H20) comes from the soil absorbed by the plants roots.

10. Where does everything come from?
Light energy comes from the sun and is captured by chloroplasts.

11. Chloroplasts
Chloroplasts capture light energy and are found mainly in the LEAVES.

12. !REVIEW! What are the 3 reactants and how do they get into a plant?
WATER----The roots
Carbon Dioxide---The stomata
Light---The chloroplast.
Is photosynthesis catabolic or anabolic??

13. What organelle does photosynthesis take place in?
Chloroplast

14. Inside the chloroplast.
thylakoids – saclike photosynthetic membranes
grana – stacks of thylakoids
stroma – space outside the thylakoids

15. How plants obtain energy
Thylakoids have light-absorbing colored molecules called PIGMENTS
Chlorophyll a & b = blue/green
Xanthophyll = yellow
Carotenoids = orange/red
Anthocyanin = red/purple

16. The principle pigment in plants is chlorophyll that’s why plants appear green!!

17. This is where it starts to get confusing so listen up!!
Ok… now we have all the reactants….Lets make some SUGAR!!
This is where it starts to get confusing so listen up!!

18. The Two Phases of Photosynthesis
Phase I - Light Dependent Reaction (occurs in the thylakoids)
Light energy is absorbed and TRANSFORMED to chemical energy (ATP and NADPH molecules)
Rember Chemical energy is ATP!!

19. Video Clip Explaining Phase I of Photosynthesis – Light Dependent Reactions

20. At the end of Phase I, the plant has made ATP (energy)
What you NEED to Know!
At the end of Phase I, the plant has made
ATP (energy)
NADPH (electron carrier)
O2 (oxygen)

21. Phase II – Light Independent Reaction (or the Dark Reaction/Calvin Cycle) (occurs in stroma)
NADPH and ATP that were formed during light dependent reactions are used to make glucose

22. How plants transform energy
Calvin Cycle converts carbon dioxide into sugar using the NADPH & ATP energy from the light-dependent reactions.
The enzyme Rubisco also helps!

23. Light Independent Reaction (The Dark Reaction) (Calvin Cycle)
ATP and NADPH contain a high amount of energy, but are short stores (no longer than a few minutes).
So plants use the ATP and NADPH to build GLUCOSE which can be stored for a longer time.

24. The Calvin Cycle Does not require light.
6 carbon dioxide molecules are required from the atmosphere
ATP & NADPH powers the cycle

25. Not On FIB write down
The Enzyme Rubisco helps build the glucose molecule during the Calvin cycle.

26. Reactants & products
The Calvin Cycle uses 6 molecules of CO2 to produce a single 6-Carbon sugar molecule called glucose.
Uses for sugars include: form starches & cellulose. When other organisms eat plants, they can also use the energy stored in carbohydrates.

27. And Now a boring person explaining it

28. Summary of Photosynthesis
Light Reactions
Dark reactions (Calvin cycle)
Inputs:
Light
Water
Outputs:
ATP
NADPH
Oxygen (O2)
OCCURS IN THYLOKOID
Inputs:
◦ ATP
◦ NADPH
◦ CO2
Outputs:
◦ Sugars
OCCURS IN THE STROMA

29. Summary
Phase I Phase II

30. Let’s review…
Light-dependent reactions
Light-independent reactions

31. What materials come into the chloroplast that are used in the light-dependent reactions?

32. What material comes into the chloroplast that is used by the Calvin Cycle?

33. What material moves out of the chloroplast from the light-dependent reactions?

34. What materials move out of the chloroplast from the Calvin Cycle?

35. What materials move from the light-dependent reactions to the Calvin Cycle?

36. What materials move from the Calvin Cycle back to the light-dependent reactions?

37. Factors that can affect photosynthesis
1. Amount of water 2. Temperatures 3. Light Intensity 4. Amount of CO2

38. And Now………. THE PHOTOSYNTHESIS RAP!

39. Where in the plant cell does photosynthesis take place?
Chapter 8
Cellular Energy
8.2 Formative Questions
Where in the plant cell does photosynthesis
take place?
chloroplasts
Golgi apparatus
mitochondria
vacuoles

40. How are the C4 pathway and the CAM pathway
Chapter 8
Cellular Energy
8.2 Formative Questions
How are the C4 pathway and the CAM pathway
an adaptive strategy for some plants?
They accelerate photosynthesis.
They release more oxygen.
They help the plant conserve water.
They reduce the requirement for ATP.

42. STOP!
Using the cards provided, at your lab table, assemble the equation for photosynthesis with your lab partner(s).
On a piece of paper, each person should draw a diagram of a plant showing the typical inputs and outputs of the photosynthetic process with your lab partner (s).
Write the equation for photosynthesis on the paper as well.