Ch. 6 Photosynthesis Stuff

The 6 Forms of Energy ATP Light energy Heat energy Electrical energy Chemical energy Mechanical energy Nuclear energy ATP sugars

Energy Conversions Energy can not be created or destroyed. Cellular Respiration Ch. 7 converts chemical energy (sugar) to a different form of chemical energy (ATP). Photosynthesis Ch. 6 converts light energy to chemical energy (sugar).

The meaning of the word Photosynthesis “light” “to make”

heterotrophs autotrophs

How do plants make energy & food? Plants use light energy to create chemical energy Create Organic Compounds glucose, sucrose, cellulose, starch, & more sun ATP sugars

Photosynthesis: a Chemical Reaction Light energy C6H12O6 O2 CO2 H2O  + carbon dioxide water glucose oxygen Reactants Products Making bonds requires energy Light provides the energy! Glucose stores the energy

What do plants need to grow? The “factory” for making energy & sugars chloroplast Fuels sunlight carbon dioxide water The Helpers enzymes sun CO2 ATP enzymes sugars H2O

Photosynthesis Two Parts: Light reactions Calvin cycle light-dependent reactions Calvin cycle light-independent reactions (Dark reactions)

So what does a plant need? Bring In light CO2 H2O Let Out O2 Move Around sugars leaves shoot 6CO2 6H2O C6H12O6 6O2  + roots

Chloroplasts Leaf Leaves CO2 Chloroplasts in cell contain chlorophyll sun CO2 Leaves Chloroplasts in cell contain chlorophyll Chloroplast make ENERGY & SUGAR

Plant structure A typical mesophyll cell has 30-40 chloroplasts, each about 2-4 microns by 4-7 microns long. Each chloroplast has two membranes around a central aqueous space, the stroma. In the stroma are membranous sacs, the thylakoids. These have an internal aqueous space, the thylakoid lumen or thylakoid space. Thylakoids may be stacked into columns called grana.

A Look at Light The spectrum of color V I B G Y O R

Light Photosynthesis gets energy by absorbing wavelengths of light chlorophyll absorbs best in red & blue wavelengths & least in green

Light Reactions occurs in the thylakoid produces ATP produces NADPH releases O2 as a waste product H2O sunlight Energy Building Reactions NADPH ATP O2

Calvin Cycle occurs in the stroma builds sugars uses ATP & NADPH recycles ADP & NADP back CO2 ADP NADP Sugar Building Reactions NADPH ATP sugars C6H12O6

Putting it all together CO2 H2O C6H12O6 O2 (light energy)  + H2O CO2 sunlight ADP NADP Energy Building Reactions Sugar Building Reactions NADPH ATP sugars C6H12O6 O2

How are they connected? Respiration  Photosynthesis glucose + oxygen  carbon + water dioxide C6H12O6 6O2 6CO2 6H2O  + Photosynthesis 6CO2 6H2O C6H12O6 6O2  +  glucose + oxygen carbon dioxide + water So, in effect, photosynthesis is respiration run backwards powered by light. Cellular Respiration oxidize C6H12O6  CO2 & produce H2O fall of electrons downhill to O2 exergonic Photosynthesis reduce CO2  C6H12O6 & produce O2 boost electrons uphill by splitting H2O endergonic