8.2 Photosynthesis p230

Q: What role do pigments play in the process of photosynthesis? A: Photosynthetic organisms capture energy from sunlight with pigments. A plant looks green because green is the only light/color reflected.

Chlorophyll & Chloroplasts Pigments: light-absorbing molecules Chlorophyll: plants’ principal pigment (reflects green) absorbs light energy Chloroplasts: Where photosyn. takes place Thylakoid: photosynthetic membranes in chloroplast. Stroma: Fluid portion of chloroplast outside of thylakoid.

High-Energy Electrons Q: What are electron carrier molecules? A: A compound that can accept a pair of high-energy electrons & transfer them, along with most of their energy, to another molecule. NADP+ accepts electrons & transfers them along with energy to other molecules Converts to NADPH

An Overview of Photosynthesis What are the reactants & products of photosynthesis? Reactants (what goes in): Sunlight, water & carbon dioxide Products (what is produced): high-energy sugars & oxygen 6CO2 + 6H2O light C6H12O6 + 6O2

Light-Dependent Reaction Requires light. Water, light NADP+ & ADP go into the thylakoid. Oxygen & NADPH & ATP are produced.

Light-Independent Reaction No light needed. Reactants: NADPH, ATP, carbon dioxide Products: NADP+, ADP, Sugars

6CO2 + 6H2O light C6H12O6 + 6O2 Thylakoid Calvin Cycle

Photosynthesis Under Extreme Conditions C4 Photosynthesis-have specialized chemical pathway that allows them to capture even very low levels of CO2. CAM Plants-adapt to dry climates & use different strategy to obtain carbon dioxide while minimizing water loss.

WB pgs 119-121 Skip #9 & 15 Keep papers to review in 15 min…..