PHOTOSYNTHESIS What do you know? What do you want to know?

Photosynthesis uses sun energy to make sugar (glucose) ( Plants and algae only Autotrophs- make their own food Heterotrophs- can’t make their own food All living organisms ( including plants) use cellular respiration to get energy from their food Next slide equation

Photosynthesis EQUATION Sunlight+6CO2+ 6H20 C6H12O6 + __O2 Reactants- light , carbon dioxide, & water Products: sugar and oxygen

Light & Pigments Sunlight is “white” but contains mixtures of visible wavelengths Chlorophyll is a PIGMENT in the chloroplast of the plant cell that absorbs light Did we see chlorplasts in the onion? Why not!!!

Leaves absorb blue-violet & red-orange light very well - Green light is reflected- why plants look green!

Types of Pigments Chlorophyll a Chlorophyll b Xanthophyll Carotene Absorbs all colors of light except green Plays major role in light reactions of photosynthesis Chlorophyll b Appears yellow-green Absorbs additional light Xanthophyll Yellow pigment Carotene Red & orange pigments Major Pigments Minor Pigments

LOCATION OF PHOTOSYNTHESIS Chloroplasts organelle in plant cells Chloroplast- many hang out in the middle of the leaves ( mesophyll )

CHLOROPLAST STRUCTURE ** Chloroplast has double membrane ** Thylakoids: sac-like photosynthetic membranes Arranged in stacks called GRANA Have chlorophyll and other pigments Stroma: Fluid area surrounding thylakoids

Print this for CP!! Boozeman 5:00 Minutes

* Light-Dependent: takes place in thylakoids- * Calvin Cycle: stroma

Light Reaction Chlorophyll molecules in thylakoid capture light energy This energy releases electrons from H2O H2O then splits into O2 and H+ Oxygen is a "waste product" & escapes to the atmosphere 4 steps

So what happens to the electrons and hydrogen ions? Light Reaction So what happens to the electrons and hydrogen ions? Chloroplasts use them to make an energy-rich molecule called NADPH and ATP The overall result of the light reaction? Light + H20 Oxygen + NADPH + ATP

Light reaction is charging up the “battery” needed to synthesize sugars in Calvin Cycle - ADP and NADP+ recycle

Calvin Cycle Does NOT use light at all Can use energy that was made in light cycle to form sugar

The Calvin Cycle Occurs in the STROMA. Uses CO2 and energy powered by ATP and NADPH to produce sugar NAPDH and ATP are recycled back to the Light Cycle for “recharging”

Reactants: Products:

Two Processes Calvin Cycle Light Reaction

Online Activity 8.1- Animation of Light and Dark Cycles Page 6 –Start

Factors Affecting Photosynthesis Temperature Light intensity

Carbon Cycle