Photosynthesis

Photosynthesis The process plants use to trap the sun’s energy Energy stored as glucose (C6H12O6)

Occurs in which organelle? CHLOROPLAST!! Three major parts Intermembrane space Thylakoid Stroma

Intermembrane Space -Space that separates the two layers of chloroplast membrane

Thylakoid CHLOROPHYLL!! Flattened membrane sacs inside chloroplast Pigments contained here trap light CHLOROPHYLL!!

Stroma Fluid filled space that surrounds stacks of thylakoids (aka Grana) Reactions that convert carbon dioxide to sugar occur here

Light Dependent Reactions 1st phase of Photosynthesis Requires Light Light absorbed by chlorophyll Energy passed to electrons Electrons passed on to the……………

Electron Transport Chain Energized electrons are passed along from protein to protein embedded in the thylakoid membrane Each time losing a little energy Create ATP from ADP+P Energy used to split H2O and form Oxygen Create NADPH for use in light independent reactions

Why split H2O to make Oxygen? Used to free electrons to return to chlorophyll……. So?? so the ETC won’t run out! And…… Photosynthesis can continue!

Light Independent Reactions Melvin Calvin Do not require Light Fueled by ATP made in ETC Known as the Calvin Cycle Occur in Stroma

Calvin Cycle Takes Carbon from CO2 Forms carbohydrates Uses ATP and NADPH Takes 6 turns to create one molecule of glucose

Photosynthesis Equation 6CO2 + 6H2O=C6H12O6 + 6O2

Photosynthesis As a Process Light energy absorbed; CO2 absorbed; O2 released from water; sugar produced Plants split the water to release Hydrogen to make NADPH

Photosynthesis cont. Plants absorb light to energize electrons in the thylakoid membrane Sugars provide a more useful storage form for the energy in the electrons released from water

Energy Overview Light reactions take energy in as light and store it as ATP and NADPH Dark reactions take the energy stored in ATP and NADPH to make sugar molecules

Three Types of Plants C3 plants: Most plants are C3 These include rice, wheat, beans C4 plants: have an adaptation to grow when stomata are closed Plants In hot regions (sugarcane, crabgrass) CAM plants: desert dwelling plants that open stomata at night Cacti