Sustaining Life on Earth PHOTOSYNTHESIS Sustaining Life on Earth

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

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. http://adambharmal.wordpress.com/2012/01/16/the-chloroplast/

Absorption Spectrum

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

The Reaction The process of photosynthesis takes place within chloroplasts to produce sugars and oxygen. Chlorophyll makes it possible. 6CO2 + 6H2O (sunlight)  C6H12O6 + 6O2 Carbon Dioxide Water Glucose Oxygen

Video Clip: Photosynthesis http://videos.howstuffworks.com/discovery/29603-assignment-discovery-photosynthesis-video.htm

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

Cross Section of the Leaf

Cells and Chloroplasts

Factors Affecting Photosynthesis Light Intensity Duration CO2 Concentration Temperature Water

References www.nsw.ac.th www.emc.maricopa.edu www.unitedstreaming.com www.firstscience.com www.ch.ic.ac.uk http://www.ualr.edu/botany/chloroplast.jpg

Your Group: Group 1: Pg 156-157 Group 2: Absorption of Light Energy (Pg. 158) Group 3: Photosystems Capture the energy (Pg 159) Group 4: The light-dependent reactions (Pg 160-161) Group 5: Making ATP by Chemiosmosis (Pg 161) Group 6: Noncyclic and Cyclic Photophosphorylation (Pg 162) Group 7: Pg 156-157 Group 8: Absorption of Light Energy (Pg. 158) Group 9: Photosystems Capture the energy (Pg 159) Group 10: The light-dependent reactions (Pg 160-161) Group 11: Making ATP by Chemiosmosis (Pg 161) Group 12: Noncyclic and Cyclicl Photophosphorylation (Pg 162)

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.