1. Chapter 8-3
Light Dependent and
Light Independent
Reactions

2. I. Basic Photosynthesis
A. Photosynthesis – the process by which autotrophs use light energy to turn carbon dioxide and water into glucose and oxygen
B. The basic equation for photosynthesis is as follows:
6CO2 + 6H2O C6H12O6 + 6O2
Sunlight
Chlorophyll

3. II. Chloroplasts B. Contains chlorophyll 1. Traps the E from sunlight.
A. Organelle where PS takes place in autotrophs
B. Contains chlorophyll
1. Traps the E from sunlight.
2. Transfers the E to the electrons (e-) in chlorophyll.
3. They are then called “high energy” electrons

4. Inside a
chloroplast

5. C. Components of Chloroplast
Thylakoid – Contains chlorophyll
Light-dependent reactions occur here
Granum –single stack of thylakoids
Grana- All of the Granum in one Chloroplast
Stroma – Region outside the thylakoid membrane-no chlorophyll
Reactions of the Calvin Cycle occur here

6. D. LIGHT DEPENDENT: reactions take. place in the thylakoid membranes
D. LIGHT DEPENDENT: reactions take place in the thylakoid membranes of chloroplast.
E. LIGHT INDEPENDENT (dark/Calvin): reactions take place in the stroma of chloroplast.

7. PLANT CELL -
High Energy Sugar
Glucose

8. III. Light Dependent Reactions

9. A. Uses energy from sun to:
1. Make ATP- ( recharged ADP + P from Calvin cycle) used in the Calvin cycle.
2. Create NADPH- from NADP+:
NADP+ comes from the Calvin cycle and it’s job is to carry the high energy electrons and the H (from water splitting) to form NADPH-
3. Oxygen gas : waste given off to environment (remember it came from the water splitting)

10. B. Water is split to produce:
1. Oxygen gas (O2)waste
2. Hydrogencarried on NADP (with high E e-) in the form of NADPH-
a. H used to make C6H12O6
b. High energy e- taken to electron transport chain (for cellular respiration)

11. III. Light Independent (dark) Reactions
A. also called Calvin Cycle
B. Produces high the energy sugar (glucose)
C. Uses ATP and NADPH- (from light reactions) to convert CO2 (from air) and H from H2O into glucose.
D. Does NOT use light energy-uses E from ATP

12. IV. Factors that Affect rate of PS
A. No water = No NADPH
If no NADPH = No Glucose
B. Temperature- enzymes sensitive to extreme temperatures
C. Light Intensity:
in light = in PS (to a certain point)
D. CO2- Carbon and oxygen atoms needed to make glucose.

13. Summary Light Dependent Reaction
Uses : Water + Light
To Make : ATP + NADPH- + (O2 as waste)
Light Independent Reaction (Calvin Cycle)
Uses: CO2 + ATP + NADPH-
To Make: glucose
***GLUCOSE IS MADE DURING DARK REACTIONS NOT LIGHT!!!!