1. Using Light Energy to Make Food
Photosynthesis
Using Light Energy to Make Food

2. Photosynthesis
Plants use energy to change carbon dioxide and water into glucose and oxygen (waste product)

3. Who performs Photosynthesis?
Plants and a few bacteria
These are called autotrophs

4. Three major events take place in two stages:
Absorption of light energy
Conversion of light energy into chemical energy (ATP and NADPH)
Storage of energy in the form of carbohydrates

5. Where does it happen? Chloroplasts: Thylakoids (a single pancake)
Contain chlorophyll
Grana (stacks)
Granum is one stack.
Stroma (thick fluid that surrounds the grana)
Where does it happen?
omega.dawsoncollege.qc.ca/ ray/cell/401cell.htm

6. Light Dependent Reaction Temperature independent Light Reaction
Light Independent Reaction
Calvin-Benson Cycle
Dark Reaction
farabee/BIOBK/BioBookPS.html

7. Light Reaction Requires direct light energy
Occurs in the thylakoids of chloroplasts
2 steps occur here:
Absorption of light by pigments
Splitting of water

8. Electron carriers Light dependent reaction They gain tons of energy!
Cells use electron carriers to transport this energy to other molecules
Called electron transport (name of process)
2 types in photosynthesis
NADP+
Carriers 2 high energy electrons and hydrogen ions
Create NADPH
ATP

9. Light Dependent Reaction (depends on light)
Inputs=sun and water
Products formed
Oxygen gas-formed by splitting water
Electrons transported to create NADPH and ATP
used in the Calvin-Benson cycle

10. Calvin Cycle Also called the dark reaction The output is glucose
Occurs in the stroma (filler in chloroplasts)
Also called the dark reaction
Carbon dioxide is the input and the NADPH and ATP from the light reaction
The output is glucose
It is used for food and energy.
Formula for glucose
C6H12O6

11. The Equation
---->
Sunlight+ 6CO H20
C6H12O

12. Factors that effect the rate of photosynthesis
Temperature
Enzymes are important for photosynthesis to work.
Enzymes work best in certain temperatures.
If the temp is too low or too high, it can decrease it or stop photosynthesis.
Light intensity
Increase light will increase photosynthesis to a point.
Amount of Carbon Dioxide
Amount of water

13.
Username: cebrainpop
Password: tiger1