Regents Biology

Regents Biology Photosynthesis: Life from Light and Air

Regents Biology Energy needs of life  All life needs a constant input of energy  Animals = Heterotrophs  get their energy from “eating others”  eat food = other organisms = organic molecules  make energy through respiration  Plants = Autotrophs  get their energy from “self”  get their energy from sunlight  build organic molecules (food) from CO 2  make energy through photosynthesis

Regents Biology Photosynthesis This is the equation you are used to seeing, but this is not the whole story… + water + energy  glucose + oxygen carbon dioxide 6CO 2 6H 2 O C 6 H 12 O 6 6O 2 light energy  +++

Regents Biology How do plants live?  Photosynthesis  Energy building reactions  collect sun energy  make ATP  Sugar building reactions  use ATP for energy  use CO 2 as carbon for new sugars  build sugars  glucose, cellulose, starch  build all other organic molecules  proteins, lipids, carbohydrates, DNA  store energy for future use  starch in seeds & roots

Regents Biology Photosynthesis  Actually 2 separate reactions  Energy building  use sunlight  make energy (ATP)  Sugar building  use ATP  use CO 2  make sugars (C 6 H 12 O 6 ) Energy building reactions Sugar building reactions sun ATP ADP CO 2 sugar

Regents Biology CO 2 Chloroplasts Leaf Chloroplast absorb sunlight & CO 2 make energy & sugar Chloroplasts contain Chlorophyll

Regents Biology Energy Building Reactions O2O2 H2OH2O Energy Building Reactions sunlight ATP H2OH2O O2O2 light energy  ++  makes ATP energy  releases oxygen as a waste product

Regents Biology Sugar Building Reactions sugars C 6 H 12 O 6 CO 2 Sugar Building Reactions ATP CO 2 C 6 H 12 O 6 ADP ATP  ++ ADP  builds sugars  uses ATP  cycles ADP back to make more ATP

Regents Biology Putting it all together sugars C 6 H 12 O 6 CO 2 ATP ADP H2OH2O O2O2 sunlight CO 2 H2OH2O C 6 H 12 O 6 O2O2 light energy  +++ Sugar Building Reactions Energy Building Reactions Plants make both:  ATP  sugars

Regents Biology  Bring In  CO 2 H2OH2O  light  Let Out O2O2  Move Around  sugars So what does a plant need? 6CO 2 6H 2 O C 6 H 12 O 6 6O 2 light energy  +++ roots shoot leaves

Regents Biology Leaf Structure H2OH2OCO 2 O2O2 H2OH2O phloem (sugar) xylem (water) stomate guard cell palisades layer spongy layer cuticle epidermis  gases in & out  water out  transpiration O2O2

Regents Biology Stomates  Function of stomates  CO 2 in  O 2 out  H 2 O out guard cell stomate

Regents Biology

Xylem carry water up from roots

Regents Biology Phloem: food-conducting cells  carry sugars around the plant wherever they are needed  new leaves  fruit  seeds

Regents Biology Putting it all together  Making a living…  sunlight  leaves = solar collectors  photosynthesis  gases: CO 2 in & O 2 out  stomates = gases in & out H2OH2O  roots take in water from soil  pulled up by leaf evaporation  nutrients  roots take in from soil

Regents Biology How are they connected? glucose + oxygen  carbon + water + energy dioxide C 6 H 12 O 6 6O 2 6CO 2 6H 2 OATP  +++ Respiration + water + energy  glucose + oxygen carbon dioxide 6CO 2 6H 2 O C 6 H 12 O 6 6O 2 light energy  +++ Photosynthesis

Regents Biology H2OH2O Energy cycle Photosynthesis Cellular Respiration sun The Great Circle of Life! Where ’ s Mufasa? glucose O2O2 CO 2 plants animals, plants ATP

Regents Biology 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 Then all the cats, dogs, mice, people & elephants… are really strands of air woven together by sunlight! sun air

Regents Biology Any Questions??