Photosynthesis in Detail

Leaf

Cell

Chloroplast

Key Questions to Keep In Mind

Why is oxygen released?

What is the purpose of water?

What is the purpose of carbon dioxide?

http://www.bio.davidson.edu/courses/Bio111/Photosynth/PS.html

Photosynthesis Phase 1: The Light Reactions

Electron Transport Chain

Chemiosmosis: The diffusion of ions across a membrane. The difference in concentration of H+ ions causes a pH gradient, too.

Photosynthesis Phase 1: The Light Reactions

Reactants:

Products:

Photosynthesis Phase II—The Calvin Cycle or Light Independent Reactions

Light Energy + 6H2O + 6CO2 C6H12O6 + 6O2Electron Transport used the reactants _______ and _______ to release _____ as a waste product and _______ and_______ as products. Therefore, the Calvin Cycle must use _________, _______, and _______as reactants and produce _______ as a product.

Photosynthesis Phase 2: The Dark Reactions

Step 1— CO2 combines with a 5-carbon carbohydrate (RuBP). The product, a six-carbon molecule, splits into a two three carbon PGA molecules.

Step 2—Each PGA receives a phosphate from an ATP, then receives a proton from NADPH and releases a phosphate group. This produces one PGAL molecule.

Step 3—Most PGAL is converted back to RuBP to be reused in the Calvin Cycle. Some PGAL leaves the Calvin Cycle and is used to produce organic compounds such as glucose.

Key Observations