1. Discuss the following cartoon with a partner.
Which of the above responses is MOST correct?
Learn the answer in THIS VIDEO.

2. Cellular Processes
Photosynthesis

3. What is Photosynthesis?
process whereby light energy from the sun is converted to chemical energy stored in the bonds of sugar (glucose)
occurs in the chloroplasts of plants, algae, and some bacteria

4. Overall Equation for Photosynthesis

5. Understanding Chemical Equations
Reactants are on the left side of the equation
Products on the right side of the equation
Reactants  Products
Reactants yield Products
A + B  C + D

6. Photosynthesis
Carried out in two phases:
Light-Dependent Reaction
Requires light energy
Light-Independent Reaction
Does not require light energy
Also known as Calvin Cycle

7. Overview of Photosynthesis

8. PHASE 1: LIGHT-DEPENDENT REACTION
Thylakoid
Occurs in the thylakoids within the chloroplast

9. PHASE 1: LIGHT-DEPENDENT REACTION
Light splits the water molecule at the thylakoids
H2O is broken down into Hydrogen ions, an electron, and Oxygen atom
Oxygen is released to the atmosphere
Hydrogen is kept to make NADPH, an energy storage molecule
Electrons are passed into the next step, the electron transport chain

10. PHASE 1: LIGHT-DEPENDENT REACTION
Electron Transport Chain (ETC)
made of proteins that accept and transfer the electrons
electrons pass from protein to protein along the ETC

11. PHASE 1: LIGHT-DEPENDENT REACTION
Formation of NADPH and ATP
Electrons at the end of the “chain” are used to make NADPH from NADP+
NADP+ + 2e- + H+  NADPH
NADPH is an energy carrier molecule that takes energy to the stroma for the Calvin Cycle
Phosphate is added
to ADP to form ATP
and is carried to the
Calvin Cycle

12. Energy Currency = ATP Chemical Energy and ATP
Energy can be stored in many forms:
Light
Heat
Electricity
Chemical Bonds!

13. Energy Currency = ATP (Video)
Bonds = Energy

14. Energy Currency = ATP
Energy in ATP is released when it is converted to ADP
The characteristics of ATP make it an exceptionally useful molecule that is used by all types of cells as their basic energy source

15. PHASE 2: LIGHT-INDEPENDENT REACTION
Occurs in the stroma, the colorless fluid that fills the chloroplast
Stroma

16. PHASE 2: LIGHT-INDEPENDENT REACTION
NADPH and ATP lose their stored energy and hydrogen is fixed to CO2 to build glucose
six molecules of carbon dioxide enter the Calvin Cycle and eventually produce one molecule of glucose (C6H12O6)
6 molecules of Carbon Dioxide
1 molecule glucose

17. Overview of Photosynthesis

18. SUMMARIZE: 3-2-1 Tell me 3 steps of the light-dependent reaction
2 phases in photosynthesis
1 main goal of photosynthesis