1. Light reaction Dark reaction
Photosynthesis
Light reaction Dark reaction

2. Key components of the Light Reaction
2 photosystems
2 electron transport chains
ATP synthase
Embedded in the _________
Which organelle? _________

3. The photosystems, 1 & 2 They are an array of _________molecules
What do these molecules do?
Hint:
They absorb light energy
And, the absorbed energy excites its electrons to a higher energy level

4. Photosystem 1 Energized electrons are passed down an ____________
What do these electrons end up doing?
Hint:
They are added to NADP+ to form NADPH

5. Photosystem 2
Meanwhile energized electrons are passed down another ____________
What do these electrons end up doing?
Hint: H+
Their energy is used to pump H+
From the __________ into the ___________ compartment

6. What does pumping H+ ions cause?
Hint:
What does pumping H+ ions cause?
Concentration gradient
Where do these electrons go? And, why?
Hint:
To photosystem 1
To replenish its lost electrons
How does this photosystem replenish its electrons?
Hint:
By splitting water

7. So, photosystem 1 is thought of as the:
Hint:
The NADPH producing photosystem
And, photosystem 2 is thought of as the:
Hint:
The water splitting photosystem

8. What is the ‘tally’ of energy production so far?
Hint:
Hint:
What about ATP?
Remember the hydrogen ions?
The buildup of __________ inside the ___________ compartment stores __________ energy.

9. The potential energy is harvested by what enzyme?
Hint:
ATP synthase
And, how is ATP made? 1 2 3 4 5 6 3 2 5 4 6 1

10. Next, the ‘sugar-producing’ Calvin cycle
The final look at energy production from the light reaction:
NADPH
ATP
No sugar produced in the light reactions!

11. The Calvin cycle What energy does the Calvin cycle use?
Hint:
NADPH
ATP
What else does the Calvin cycle need to get started?
CO2

12. A quick rundown of the Calvin cycle tells us that:
Carbon is used from _________
Energy is used from _________
High energy electrons are used from ______
The cycle itself produces an energy-rich molecule called _________
The plant cell uses ______ as raw material to make ________

13. Called a cycle because:
Regenerates the starting material with each turn of the cycle
What is the cycle?
A complex series of chemical reactions
Where does it occur?
In the stroma of the chloroplast

14. What is the carbon bound to?
The cycle begins with:
Input of CO2
(how many?)
What is the carbon bound to?
RuBP molecules
(how many?)
But, what happens to RuBP?
Its broken up into 3-PGA
RuBP: ribulose bisphosphate, a 5 carbon sugar
3-PGA: 3-phosphoglyceric acid, a 3 carbon compound

15. What happens to ATP, NADPH?
What is the next step?
G3P?
3 PGA?
Energy is required
To convert __________ to product __________
What happens to ATP, NADPH?
G3P: glyceraldehyde 3-phosphate, a 3 carbon sugar

16. Half way around the cycle…
CO2
3 PGA
RuBP
Does this diagram represent one or more turns of the cycle?
G3P
What is the name of this molecule?

17. What happens with one full turn of the cycle?
G3P
3 PGA
CO2
Starting material _______ is regenerated
How many molecules of direct product are produced at this point?

18. One complete cycle …
How many cycles to make one glucose?

19. Depending on the needs of the plant, what are some facts about G3P?
Some G3Ps are used to build glucose
Glucose can combine into starch
Or cellulose

20. Still other G3P’s form sucrose
Some sugar is broken down by cellular respiration
Uses oxygen in the plant’s own mitochondria
Generates ATPs that powers other work of the plant
Excess oxygen diffuses out of the leaf through the pores, while more CO2 enters

21. Learning check
The Calvin cycle must turn ______ times for the plant to be able to produce a single molecule of glucose.
What is the function of NADPH in the Calvin cycle?
The Calvin cycle takes place in the ______.