Biology -- Photosynthesis

Photosynthesis Equation

6H2O + 6CO2 -→ 602 + C6H12O6

Reactants of Photosynthesis

Carbon Dioxide, NADPH, ATP

Products of Photosynthesis

Glucose (C6H12O6), NADP+, ADP

Step 1

Chlorophyll in PS2 absorbs light energy

Step 2

energy excites a pair of electrons

Step 3

excited electron pair moves along the electron transport chain

Step 4

high energy electrons are used to move H+ from the Stroma to the Thylakoid space

Step 5

electrons lost from chlorophyll are replaced by photolysis (H2O → 2e-) H2O → 2H+ + 1/2 O2 + 2e-

Step 6

O2 is released to the environment

Step 7

Chlorophyll in PS1 absorbs sunlight & energizes 2e-

Step 8

NADP+ picks up 2e- & 1 H+ to form NADPH and moves to the stroma. Low energy e- from PS2 replaces lost e- in PS1

Step 9

Pile up of H+ in thylakoid space moves through ATP synthase into the stroma. Movement converts ADP to ATP

3 parts of the Calvin Cycle

Carbon fixation, reduction, regeneration

Carbon Fixation

3 RuBP (5-C) molecules “fixing” 3 CO2 molecules. This producing 6 PGA (3-C) molecules

Reduction

3 PGA molecules + 6 ATP + 6 NADPH molecules produce 6 G3P (3-C) molecules

Regeneration

5 G3P molecules are used to regenerate 3 RuBP molecules to continue the Calvin Cycle. This step requires 3 additional ATP molecules.