Chloroplast & Photosynthesis

site of Photosynthesis

Chemical Equation

Energy + 6CO2 + 6H2O → C6H12O6 + 6O2

Stages of Photosynthesis

1. Light Rxn

2. Dark Rxn/Calvin Cycle

Where does the light rxn occur?

thylakoid membranes

Where does the dark rxn occur?

stroma

Light RXN

needs light to occur

converts light energy into chemical energy (ATP & NADH)

light is used to split water & later release O2

Calvin Cycle

no light needed

uses ATP & NADH to convert CO2 into the sugar G3P

returns ADP into inorganic phosphate & NADP to the light rxns

Photosystem II

occurs 1st

best at absorbing wavelength of 680 nm

Photosystem I

occurs 2nd

best at absorbing wavelength of 700 nm

Cyclic Electron Flow (CEF)

1. electrons cycle back to cytochrome complex & back into PS I rxn center\

2. uses only PS I

3. produces ATP ONLY (NO NADPH or O2)

4. occurs when ATP levels drops and NADPH levels rise

Non-Cyclic

1. forms ATP & NADPH

2. e- flow from H2O to PS II to PS I to NADPH

3. makes O2 from splitting H2O

4. makes ATP from H+ gradient

Non-Cyclic

1. uses only PS I

2. only ATP is produced

3. no splitting of water (e- come from light harvesting complex)

G3P

monomer used to make glucose

Calvin Cycle Inputs & Outputs

3 molecules of CO2 = 1 G3P

2 G3P = 1 glucose

6 turns → 2 G3P → 1 glucose

Clavin cycle uses…ATP & …NADH to produce…glucose

1. 18

2. 12

3. 1

The 3 stages of Calvin Cycle

1. Carbon Fixation

2. Reduction

3. Regeneration of Co2 acceptor RuBP