1. Photosynthesis

3. Comparing Photosynthesis & Respiration
Cellular Respiration
Function
Energy Storage
Energy Release
Location
Chloroplasts
Mitochondria
Reactants
CO2 and H2O
C6H12O6 and O2
Products
Equation
6CO2 + 6H2O  C6H12O6 + 6O2
C6H12O6 + 6O2
6CO2 + 6H2O

4. Mitochondrion and Chloroplast structure

5. Photosynthesis overview
Process of storing energy in sugar molecules from the energy initially in the sun (radiant energy)
1st step: Capture radiant energy and use it to generate our “energy currency”
2nd step: Use “energy
currency” to convert
CO2 to glucose
Oxygen is released
as a byproduct
Happens in the
chloroplast

6. WHY ARE PLANTS GREEN? It has to do with sunlight!
Sunlight is a form of electromagnetic energy, which travels in waves.

7. WHY ARE PLANTS GREEN?
Different wavelengths of visible light are seen by the human eye as different colors.
Gamma rays
Micro- waves
Radio
waves
X-rays UV
Infrared
Visible light
Wavelength (nm)

8. The feathers of male cardinals are loaded with carotenoid pigments
The feathers of male cardinals are loaded with carotenoid pigments. These pigments absorb some wavelengths of light and reflect others.
Reflected light
Sunlight minus absorbed wavelengths or colors equals the apparent color of an object.

9. Plant pigments
Pigments are materials that absorb particular wavelengths of light and reflect others
When chlorophyll absorbs light, energy is transferred to electrons and “boosts” them to a higher state.
Plant pigments

10. Chloroplast Pigments Chloroplasts contain several pigments
Chlorophyll a: absorbs mainly violet and red light the best
Chlorophyll b: absorbs blue and orange light the best
Carotenoids: absorbs blue and green best
Figure 7.7

11. Different pigments absorb light differently

12. Photosystems: Clusters of pigments in thylakoid membrane
Photosystem I
Traps light energy and transfers the light-excited electrons to an electron transport chain.
Those excited electrons are replaced by splitting a molecule of water, which releases oxygen.
The electron transport chain releases energy, which is used to make ATP
Photosystem II
Produces NADPH by transferring excited electrons and hydrogen ions to NADP+.

13. Light Reactions Photosystem I and Photosystem II
SUMMARY: In the light reactions, electron transport chains generate ATP, NADPH, & O2
Two connected photosystems collect photons of light and transfer the energy to chlorophyll electrons
The excited electrons are passed from the primary electron acceptor to electron transport chains
The light reactions convert light energy to the chemical energy of ATP and NADPH
Watch the following animation:

14. Two types of photosystems cooperate in the ight reactions Inputs:
Water
Sunlight energy
Outputs:
Oxygen
ATP
NADPH
Photon
ATP
mill
Photon
Water-splitting
photosystem
NADPH-producing
photosystem

15. Plants produce O2 gas by splitting H2O
The O2 liberated by photosynthesis is made from the oxygen in water (H+ and e-)

16. ELECTRON TRANSPORT CHAIN
The production of ATP in photosynthesis
Thylakoid compartment (high H+)
Light
Light
Thylakoid membrane
Antenna molecules
Stroma (low H+)
ELECTRON TRANSPORT CHAIN
PHOTOSYSTEM II
PHOTOSYSTEM I
ATP SYNTHASE

17. A Photosynthesis Road Map
Chloroplast
Light
Stroma
NADP
Stack of
thylakoids
ADP
+ P
Calvin
cycle
Light
reactions
Sugar used for cellular respiration

18. Light reactions Role of chlorophyll:
Photosystem
Role of chlorophyll:
Capture energy from light
Role of an electron carrier: transport electrons
Tracking electrons and energy
NADP+ + 2e- + H+  NADPH

20. Calvin Cycle Location- Purpose- Input – Output – Tracing carbon
Factors affecting photosynthesis

21. Calvin Cycle
Called a cycle because the starting material, RuBP, is regenerated.
Uses carbon from carbon dioxide, the energy from ATP, and high energy electrons and hydrogen ions from NADPH to make a small sugar named G3P.
The plant uses G3P to make glucose and other organic molecules.
Overall input:
CO2, ATP, NADPH
Overall output:
Glucose

23. Calvin Cycle Watch the following animation:

24. Review: Photosynthesis uses light energy to make food molecules
Light reactions use water and produce oxygen.
The Calvin Cycle uses ATP and NADPH created in the the light reactions to convert carbon dioxide to glucose.
Chloroplast
Light
Photosystem II Electron transport chains Photosystem I
CALVIN CYCLE
Stroma
Electrons
Cellular respiration
Cellulose
Starch
Other organic compounds
LIGHT REACTIONS
CALVIN CYCLE

25. Fill out the following chart to compare Photosynthesis and Cellular Respiration
Function
Location
Reactants
Products
Equation

26. Photosynthesis – Cellular Respiration comparison
Function
Energy capture
Energy release
Location
Chloroplasts
Mitochondria
Reactants
CO2 and H2O
C6H12O6 and O2
Products
Equation
6CO2 + 6H2O light> C6H12O6 + 6O2
6O2 + C6H12O6  CO2 +6H2O + energy