PhotosynthesisPhotosynthesisTurning Light into LifeTurning Light into Life

What is Photosynthesis?What is Photosynthesis?Autotrophs Autotrophs

convertconvert Sunlight Sunlight to Chemical to Chemical

EnergyEnergy

Plants providePlants provideChemical energy on which all life dependsChemical energy on which all life dependsOxygen – plants created our atmosphereOxygen – plants created our atmosphereMaterials – shelter, clothing, medicineMaterials – shelter, clothing, medicineFood – for (almost) all other life formFood – for (almost) all other life form

All the catching of facts All the catching of facts is done for youis done for you

All the breaking down of All the breaking down of complex information is complex information is done for youdone for you

All the digesting of All the digesting of difficult chemical difficult chemical formulas is done for youformulas is done for you

All you have to do is All you have to do is swallow it!swallow it!

Photosynthesis the easy wayPhotosynthesis the easy way

COCO22 + + HH22OO CC66HH1212OO66 + + OO22

Materials Required for Photosynthesis:Materials Required for Photosynthesis: Sunlight – provides energySunlight – provides energy Carbon Dioxide – provides carbon Carbon Dioxide – provides carbon Water – provides electronsWater – provides electrons & enzymes to put everything together!& enzymes to put everything together! Oxygen is a “waste product” after Oxygen is a “waste product” after

electrons have been removed from waterelectrons have been removed from water

Where does Where does photosynthesis take photosynthesis take

place?place?

http://extension.oregonstate.edu/mg/botany/images/fig12a-small.gif

Leaf StructuresLeaf Structures• Cuticle & epidermis protect plantCuticle & epidermis protect plant• Stomates allow gases in and outStomates allow gases in and out• Veins in leaf transport water, Veins in leaf transport water,

nutrientsnutrients• Xylem - water & minerals up from Xylem - water & minerals up from

rootsroots• Phloem - food from leaves to plantPhloem - food from leaves to plant

Leaf StructuresLeaf Structures• Mesophyll = middle leafMesophyll = middle leaf

• Palisade layer is where most Palisade layer is where most photosynthesis takes placephotosynthesis takes place

• Cells have many chloroplastsCells have many chloroplasts

• Spongy mesophyll allows gases to Spongy mesophyll allows gases to circulatecirculate

Chloroplasts are organelles within plant

cells with liquid (stroma) and

stacks of membranes

(grana)

Thylakoids – membranesthat form grana

Photosystems Photosystems Clusters of chlorophyll molecules in Clusters of chlorophyll molecules in

thylakoids that absorb light energy thylakoids that absorb light energy

http://kvhs.nbed.nb.ca/gallant/biology/thylakoid.jpghttp://kvhs.nbed.nb.ca/gallant/biology/thylakoid.jpg

Narrate this movie! Narrate this movie!

Pigments and ColorPigments and Color Chlorophyll a – most Chlorophyll a – most

important pigment in important pigment in photosynthesisphotosynthesis

Other pigments Other pigments are also presentare also present

Chlorophyll aChlorophyll a Chlorophyll aChlorophyll a

absorbsabsorbs blueblue & red light& red light

Chlorophyll a Chlorophyll a reflectsreflects green/green/yellowyellow lightlight

That’s why That’s why leaves look leaves look greengreen!!

Light Reactions - the BasicsLight Reactions - the Basics