2006-2007

Photosynthesis: Life from Light and Air 2006-2007

Plants are energy producers Like animals, plants need energy to live unlike animals, plants don’t need to eat food to make that energy Plants make both FOOD & ENERGY animals are consumers plants are producers

How do plants make energy & food? Plants use the energy from the sun to make ATP energy to make sugars glucose, sucrose, cellulose, starch, & more sun ATP sugars

Building plants from sunlight & air Photosynthesis 2 separate processes ENERGY building reactions collect sun energy use it to make ATP SUGAR building reactions take the ATP energy collect CO2 from air & H2O from ground use all to build sugars ATP H2O + CO2 sugars carbon dioxide CO2 water H2O sugars C6H12O6 +

Using light & air to grow plants Photosynthesis using sun’s energy to make ATP using CO2 & water to make sugar in chloroplasts allows plants to grow makes a waste product oxygen (O2) (ATP) = used to build the sugar  glucose + oxygen carbon dioxide sun energy + water + 6CO2 6H2O C6H12O6 6O2 sun energy  +

What do plants need to grow? The “factory” for making energy & sugars chloroplast Fuels sunlight carbon dioxide water The Helpers enzymes Make ATP! Make sugar! I can do it all… And no one even notices! sun CO2 ATP enzymes sugars H2O

Photosynthesis ATP ADP ENERGY building reactions sun Photosynthesis ENERGY building reactions ADP ATP SUGAR building reactions used immediately to synthesize sugars H2O sugar CO2

Chloroplasts are only in plants animal cells plant cells

Chloroplasts absorb sunlight & CO2 Leaf Leaves CO2 Chloroplasts in cell Chloroplast Chloroplast Chloroplasts contain Chlorophyll make ENERGY & SUGAR

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

Leaf Structure vascular bundle (vein) xylem (water) phloem (sugar) cuticle epidermis palisades layer spongy layer epidermis stomate guard cells cuticle

Transpiration xylem (water) stomate guard cells CO2 in O2 out H2O CO2 stomate guard cells CO2 in O2 out water out so it gets to leaves from roots O2 H2O CO2

Transpiration Water evaporates from the stomates in the leaves pulls water up from roots water molecules stick to each other more water is pulled up tree from ground

Function of Leaf Structures Cuticle waxy coating reduces water loss Epidermis skin protecting leaf tissues Palisades layer high concentration of chloroplasts collecting sun’s energy photosynthesis making ATP & sugars Spongy layer air spaces gas exchange CO2 in for sugar production, remove waste O2

Stomates & Guard Cells guard cell stomate Function of stomates CO2 in O2 out H2O out gets to leaves for photosynthesis Function of guard cells open & close stomates guard cell stomate

Guard cells & Homeostasis keeping the internal environment of the plant balanced Stomates open let CO2 in needed to make sugars let H2O out needed for photosynthesis let O2 out get rid of waste product Stomates close if too much H2O evaporating

Xylem carry water up from roots

Phloem: food-conducting cells carry sugars around the plant wherever they are needed new leaves fruit & seeds roots

glucose + oxygen  carbon + water + energy How are they connected? Respiration glucose + oxygen  carbon + water + energy dioxide C6H12O6 6O2 6CO2 6H2O ATP  + Photosynthesis 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 6CO2 6H2O C6H12O6 6O2 light energy  +  glucose + oxygen carbon dioxide sun + water +

The Great Circle of Life! sun Energy cycle Photosynthesis plants H2O CO2 glucose sugars O2 animals, plants Cellular Respiration ATP The Great Circle of Life! Mufasa?

organic molecules food consumers, heterotrophs release chemical energy sun Another view… capture light energy Photosynthesis synthesis producers, autotrophs H2O CO2 organic molecules food O2 waste waste waste consumers, heterotrophs digestion Cellular Respiration ATP release chemical energy

The poetic perspective All of the solid material of every plant was built out of thin air All of the solid material of every animal was built from plant material sun air Then all the cats, dogs, mice, people & elephants… are really strands of air woven together by sunlight!

Got the energy… Ask Questions!! 2006-2007