Photosynthesis Chapter 8

Organisms that use Photosyntheis Anozygenic Purple bacteria Green sulfur bacteria Green nonsulfur bacteria Heliobacteria Oxygenic Cyanobacteria Some algae All land plants

Where does photosynthesis happen?

Parts of the Chloroplast Thylakoid Membrane – where photosystems are found Grana Chlorophyll Stroma

3 Stages of Photosynthesis 1. Capturing energy from sunlight 2. Using the energy to make ATP and to reduce the compound NADP+ to NADPH 3. Using the ATP and NADPH to power the synthesis or organic molecules from CO2 in the air

Story Time- History of Photosynthesis Helmont Priestly Jan Ingen-Housz F.F. Blackman C.B. van Niel

Pigments Photons- Short wavelength vs Long Wavelength Can cause photoelectric effect

Chlorophyll Absorption Spectra Chlorophyll b Both can’t absorb 500-600nm…what color do you think this is?

Accessory Pigments Caroteniods- ex Beta-carotene Phycobiloproteins

Photosystem Organization Antenna Complex Reactions Ceneter

Antenna Complex Captures photons from sunlight and channels them to the reactions center chlorophylls

Reaction Center Figure 8.10 In plants water serves as an electron donor, when water is oxidized oxygen is released along with two protons

Light-Dependant Reactions Primary Photoevent Charge Separation Electron Transport Chemiosmosis ALL OCCUR IN THE THYLAKOID MEMBRANE!!!!!!!!!!!!

Photosystems Chloroplasts have two photosystems…sulfur bacteria have 1 what does this suggest. Photosystem 1- 700nm Photosystem 2- 680 nm Cytochrome b6-f complex Cyclic vs noncyclic

Video Break Photosystems

And Now for a Video Break Photosynthetic Electron Transport System and ATP Synthase

So What is made? For every Electron Pair 1 molecule of ATP is made…but this is not enough to drive carbon fixation…how do they cope? NADPH is also Made

Carbon Fixation Converts inorganic carbon into organic molecules Calvin cycle 3 phases Carbon Fixation Reduction Regeneration of RuBP

Calvin Cycle Calvin Cycle

Photorespiration Releases CO2 Reduces the yield or photosynthesis As Temperature rises C3 respiration becomes less favorable

Coping with High Temperatures C4 pathway- Captures CO2 in one cell and the decarboxylation occurs in an adjacent cell. Corn, sugarcane, grasses. CAM pathway- stomata open during the night and close during the day Cacti, pineapples, and some other plants