1. Photosynthesis
Defintition: A molecular process where organisms create energy from sunlight
Vocabulary
Organelles
NADP+ / NADPH
ADP / ATP
Chlorophyll
Chloroplast
Glucose
Light Reactions
Dark Reactions

2. Cell Theory
What do we remember about a living cell? In your notebook draw what you might think a cell looks like.

3. Cell Theory

4. Cell Theory
Basically we need to remember that cells are very small building blocks for living organisms
There are many small parts to a cell – We call these “organelles”
Organelles help the cell perform different functions
nucleus= holds DNA, gives instructions
Cell wall= Separates inside from outside
Mitochondria= powerhouse
In plant cells specifically, one ‘Job” of the cell is to help turn sunlight into energy

5. 6H2O + 6CO2 ----------> C6H12O6+ 6O2
Photosynthesis!
Pigments, such as chlorophyll absorb sunlight
Chlorophyll is found in leaf cells
Plant leaves have openings (called stomata) where Carbon Dioxide enters
Water is brought into a plant by the roots
6H2O + 6CO > C6H12O6+ 6O2
light
chlorophyll

6. CHLOROPLAST CROSS-SECTION
This is where photosynthesis occurs…

7. Look at all
the detail!

8. Inside a Chloroplast Photosynthesis takes place in the chloroplasts.
Thylakoids are saclike photosynthetic membranes – where light-dependent reaction takes place.
Thylakoids arranged in stacks called grana
Photosystems – made of pigments and chlorophyll and are used to collect light.

9. Why are plants green?

10. Why are plants green?
Plants are green because plants want to absorb the high energy wavelengths of UV radiation (purple/blue) and the low energy wavelengths of red/orange light (produced by sun)
We know that things appear the color they are, because they are actually reflecting (rather than absorbing) that type of light away from their surface.
Since plants don’t have much use for waves in the green spectrum, they reflect it, causing them to have a green appearance

11. 6H2O + 6CO2 ----------> C6H12O6+ 6O2
Why Photosynthesis!
The chloroplast contains pigments
Pigments, such as chlorophyll absorb sunlight
Chlorophyll is found in leaf cells
Plant leaves have openings (called stomata) where Carbon Dioxide enters
Water is brought into a plant by the roots
light
6H2O + 6CO > C6H12O6+ 6O2

12. To simplify the very complex process of photosynthesis, we are going to split up the process into 2 stages (Light and Dark).
Stage #1= The Light-dependent reaction takes place in the thylakoid membranes.
Stage #2 =The Dark (light-independent) reaction takes place in the stroma – region outside the thylakoid membranes. AKA – The Calvin Cycle

13. Light-Dependent Reactions
Requires sunlight!
Sunlight → Absorbed by chlorophyll in the thylakoid (electrons) → electron transport chain → splits water and makes ATP
Light energy is converted to chemical energy in the form of ATP

14. Electron Transport Chain
Sunlight excites electrons in the chlorophyll – Excited electrons must follow specific paths in the cells.
Cells use the “Electron transport Chain” (ETC) to transport these high energy electrons.
NADPH (light energy stored as a chemical) can carry high energy electrons to other chemical reactions in the cell

15. Light-Dependent Reactions Continued
As the ETC is occurring, water from the thylakoid membrane is split – the hydrogen atoms donate their electrons
OXYGEN is released as the byproduct!
Energy is used to transport H+ ions from stroma to thylakoid membrane
H+ ions fill the inside of the cell and react with ATP synthase to create ATP

16. Main Ideas – Light Dependent Reactions
Reactants = Sunlight, Water, ADP, NADP+
Products = Oxygen, ATP, NADPH

17. Light-Dependent Reactions Continued

18. Light-Independent Reaction (Calvin Cycle)
Does not need light
Use products of light-dependent reactions (Oxygen, ATP, NADPH)
Occurs in the stroma of the chloroplast
Calvin Cycle – use energy that ATP and NADPH contain to make compounds (glucose)

19. Light-Independent Reaction (Calvin Cycle)
Takes in 6 CO2 molecules to make larger carbon molecules which are chemically transformed through the cycle
Two carbon molecules removed to be used as plant energy/food
The remaining carbon molecules are used to help produce more ATP throughout the cycle
Cycle continues until plant runs out of Carbon Dioxide

20. Light-Independent Reaction (Calvin Cycle)
Reactants = CO2, ATP, NADPH
Products = glucose, water, ADP, NADP+
The cycles work together to keep the process moving!
Light-dependent traps the energy
Calvin Cycle (Light Independent) uses the energy to produce stable, high energy sugars

21. Equation for Photosynthesis
6H2O + 6CO > C6H12O6+ 6O2
Definition – the process plants use to trap the Sun’s energy with chlorophyll and use the energy to convert carbon dioxide and water to simple sugars that store energy
This reaction is ENDOTHERMIC – requires input of energy (sunlight)
sunlight
chlorophyll