1. Sustaining Life on Earth
PHOTOSYNTHESIS
Sustaining Life on Earth

2. Photosynthetic Organisms
Plants, algae, cyanobacteria and some protists can all photosynthesize
The are organisms that transform the sun’s light energy into chemical energy
These organisms all contain the green coloured pigment called chlorophyll

3. Absorbing Light
A compound that absorbs certain wavelengths of visible light is called a pigment.
A photosynthetic pigment is a compound that traps light energy and passes it on to other compounds. Pigments embedded in the thylakoid membrane absorb light.
Leaves appear green because chlorophyl reflects green and yellow and absorbs red and blue wavelengths.

4. Absorption Spectrum

5. Pigment Types
Pigments are necessary to absorb photons of light from the sun.
Chlorophyll a
Only pigment that can transfer energy of light to electron acceptors
Absolutely necessary for photosynthesis
Chlorophyll b
Accessory pigment, absorbs photons of light different from chlorophyll a
Transfers energy to chlorophyll a
Carotenoids
Accessory pigments that absorb photons of light in the blue – violet range
Xanthophylls
Accessory pigment that turns leaves yellow in the fall
Anthocyanins
Accessory pigment that turns leaves and fruit red

6. The Reaction The process of photosynthesis takes place
within chloroplasts to produce sugars and oxygen. Chlorophyll makes it possible.
6CO H2O (sunlight)  C6H12O O2
Carbon Dioxide Water Glucose Oxygen

7. Video Clip: Photosynthesis

8. Each Part Plays a Role
Leaves – where photosynthesis happens (leaves increase surface area to absorb sunlight)
Stem – Supports the leaves, transports materials in both directions
Roots – Absorb water from the soil, anchors plant to ground

9. Cross Section of the Leaf

10. Cells and Chloroplasts

12. Factors Affecting Photosynthesis
Light Intensity
Duration
CO2 Concentration
Temperature
Water

13. References www.nsw.ac.th www.emc.maricopa.edu www.unitedstreaming.com

14. Your Group:
Group 1: Pg
Group 2: Absorption of Light Energy (Pg. 158)
Group 3: Photosystems Capture the energy (Pg 159)
Group 4: The light-dependent reactions (Pg )
Group 5: Making ATP by Chemiosmosis (Pg 161)
Group 6: Noncyclic and Cyclic Photophosphorylation (Pg 162)
Group 7: Pg
Group 8: Absorption of Light Energy (Pg. 158)
Group 9: Photosystems Capture the energy (Pg 159)
Group 10: The light-dependent reactions (Pg )
Group 11: Making ATP by Chemiosmosis (Pg 161)
Group 12: Noncyclic and Cyclicl Photophosphorylation (Pg 162)

15. Your task:
Read your section and as a group decide on the important points (10 min)
Compare the important points with the other group who read your section…. Prepare notes for class (15 min)
The six of you will put your notes on the board and explain them to the class.