Photosynthesis and Chloroplasts

Chloroplasts• All green plants have

chloroplasts- this is where photosynthesis takes place– Their green color is from

chlorophyll- which is a light absorbing pigment

– Chlorophyll is located in the thylakoids- this is where the light reactions take place

Photosynthesis• 6 CO2 + 6 H2O C6H12O6 + 6 O2

Photosynthesis• Photosynthesis produces Oxygen Gas by

splitting Water• Takes place in two stages Light reactions and

Dark reactions/ Calvin Cycle

Light reaction 1. Light absorption excites an electron and water is split to O2

2. The excited electron is then passed down an electron transport chain which passes H+ molecules across the membrane creating proton gradient

3. The proton gradient created in the ETC allows ATP Synthase to be activated to produce 18 ATP

Light Reaction

Dark Reaction/Calvin Cycle (occurs in the stroma)

• The ATP and NADPH made in the light reaction along with CO2 fuels the Calvin Cycle

• The Calvin cycle is like a sugar factory and it occurs in 4 Steps

• The Glucose made is stored for the plant’s food source (autotroph)

CAM and C4 Plants• C4 plants- have a special

adaptation that prevents photorespiration so that when the weather is really hot and dry the C4 plant can keep its stomata closed and conserve water that would be released by photosynthesis

• CAM plants- adapt to dry climates. It conserves water by opening its stomata and bringing in CO2 at night this allows the plant to close the stomata during the day but still have the CO2 to go through photosynthesis