1. How can you explain the shape of these two graphs that describe the rate of photosynthesis as a function of temperature and light intensity?
Answers:
Light intensity – this is a saturation curve graph. Initially increases light increases the production of key reaction intermediates in photosynthesis, however eventually the enzymes become saturated and the rate plateaus.
Temperature- This is a bell curve. There is an optimum temperature at which the activity of the enzymes that catalyze the reactions of photosynthesis operate most efficiently.

2. Practice IB Bioenergetics Question
The concentration of O2 was measured in the dark in a container of fixed volume for 1 hour. Next a plant was added to the container with the lights off for 1 hour. Finally high intensity lights were turned on in the container for 3 hours. Sketch a plausible graph of what would be observed during the experiment. Label the y-axis as O2 concentration and time on the x-axis.

3. [O2]
Introduce Plant in Dark
LIGHT ON
TIME

4. The Main Product of the Light-independent Reactions
In the Light-independent Reactions, the Calvin cycle uses ATP and NADPH to convert CO2 to sugar
1. Carbon fixation to a 3-carbon organic acid C3
Ribulose -1,5-bisphosphate carboxylase oxygenase
2. Reduction to an aldehyde (ATP & NADPH)
The Main Product of the Light-independent Reactions
VIDEO LINK OVERVIEW
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

5. Electron transport chain
Fig
H2O
CO2
CALVIN CYCLE INPUTS: CO2 + NADPH + ATP
Light
NADP+
ADP + P i
Light
Reactions:
Photosystem II
Electron transport chain
Photosystem I
RuBP
3-Phosphoglycerate
Calvin
Cycle
ATP
G3P
Starch
(storage)
NADPH
Chloroplast in Mesophyll cells
Chloroplast
CALVIN CYCLE OUTPUTS: G3P(or glucose) + NADP+ + ADP O2
Sucrose (export)

6. Figure 10.17 The Calvin cycle (Layer 1)
Link to Smith College Animation

7. The addition of CO2 to RuBP to form 3-PGA is catalyzed by the enzyme Rubisco
-Very inefficient enzyme
Slow rate means that many copies of enzyme are required in each chloroplast

8. Figure 10.17 The Calvin cycle (Layer 2)

9. Figure 10.17 The Calvin cycle (Layer 3)

10. 6 turns required to make 1 glucose molecules
Link to McGraw-Hill Animation

12. Link to animation Light source
Stop reaction at different time intervals by dropping sample into hot, boiling ethanol.

13. Link to Arizona Biology Project