Calvin CycleCalvin Cycle

Chapter 8 Sec. 3Chapter 8 Sec. 3

PhotosynthesisPhotosynthesis

Capturing energy from light and storing it Capturing energy from light and storing it within organic compoundswithin organic compounds

Two stages of photosynthesis: Light Two stages of photosynthesis: Light Rxns. and the Calvin CycleRxns. and the Calvin Cycle

ChloroplastChloroplast ThylakoidThylakoid – small – small

flattened sacsflattened sacs

GranaGrana – stacks of – stacks of thylakoidsthylakoids

StromaStroma – fluid – fluid solution inside solution inside chloroplastchloroplast

Light ReactionLight Reaction

Uses light energy to produce ATP and Uses light energy to produce ATP and NADPHNADPH

Occurs in the thykaloid of chloroplastOccurs in the thykaloid of chloroplast

Melvin CalvinMelvin Calvin

Calvin CycleCalvin Cycle

Uses ATP and NADPH from light reaction to Uses ATP and NADPH from light reaction to produce organic compounds (glucose)produce organic compounds (glucose)

Occurs in the stroma of chloroplastOccurs in the stroma of chloroplast

Calvin Cycle Calvin Cycle

Takes COTakes CO22, ATP, and NADPH an converts , ATP, and NADPH an converts

other carbohydrates into readily available other carbohydrates into readily available sugarssugars

Factors Affecting PhotosynthesisFactors Affecting Photosynthesis

TemperatureTemperature LightLight WaterWater

Alternative PathwaysAlternative Pathways

CC44 Pathway Pathway CAM PathwayCAM Pathway

CC44 and CAM Pathways and CAM Pathways

Occur in plants that are found in hot dry Occur in plants that are found in hot dry climates climates

Potential to lose waterPotential to lose water

StomataStomata

Small pores on the underside of the leafSmall pores on the underside of the leaf Absorb water and allow COAbsorb water and allow CO22 inside and inside and

OO22 out out

StomataStomata

If they close to keep water in then COIf they close to keep water in then CO22

levels decrease and Olevels decrease and O22 levels increase levels increase BAD !!!!BAD !!!!

C4 PathwayC4 Pathway

CO2 is fixed into a 4 carbon compoundCO2 is fixed into a 4 carbon compound Stomata is partially closed during the day Stomata is partially closed during the day

to prevent dessicationto prevent dessication

CC44 Pathway Pathway

Corn, sugar cane, and crabgrassCorn, sugar cane, and crabgrass Only lose as half as much water as normalOnly lose as half as much water as normal

CAM PathwayCAM Pathway

Cactuses and pineappleCactuses and pineapple Only open stomata at night to gather COOnly open stomata at night to gather CO22

Lose less water than CLose less water than C33 and C and C44