Regents Biology Photosynthesis: Life from Light and Air

Regents Biology 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

Regents Biology 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

Regents Biology H2OH2O 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 CO 2 from air & H 2 O from ground  use all to build sugars ATP sun sugars + CO 2

Regents Biology Using light & air to grow plants  Photosynthesis  using sun’s energy to make ATP  using CO 2 & water to make sugar  in chloroplasts  allows plants to grow  makes a waste product  oxygen (O 2 )

Regents Biology What do plants need to grow?  The “factory” for making energy & sugars  chloroplast  Fuels  sunlight  carbon dioxide  water  The Helpers  enzymes H2OH2O sugars ATP enzymes CO 2 sun

Regents Biology H2OH2O Photosynthesis ENERGY building reactions SUGAR building reactions ATP ADP CO 2 sugar sun used immediately to synthesize sugars

AP Biology  Chloroplasts  double membrane  stroma  fluid-filled interior  thylakoid sacs  grana stacks  Thylakoid membrane contains  chlorophyll molecules  electron transport chain  ATP synthase Plant structure outer membrane inner membrane thylakoid granum stroma

AP Biology Labeling the Chloroplast  Outer Membrane = I  Intermembrane Space = J  Inner Membrane = K  Granum  Thylakoid = L = GREEN!!  Stromal Lamella = M  DNA = N  Ribosome = O  Starch Grain = P  Stroma = Q

AP Biology

Lab objectives  Separate plant pigments using chromatography  Calculate Rf values for four different plant pigments  Rf value = distance pigment traveled distance solvent traveled

AP Biology Pigments of photosynthesis  Must be present for Pn to occur  Embedded in thylakoid membrane  Each pigment absorbs light of specific wavelengths  Arranged in a photosystem  Collection of pigment molecules embedded in a protein  Examples:  Chlorophyll a: ¾ of chlorophylls in green plants  Primary Pn pigment; absorbs blue and red light  Chlorophyll b: absorbs light in blue-green and orange- red spectrum  Carotenoids: absorb light in the blue and blue-green regions of the spectrum (carotenes and xanthophylls)

AP Biology Pigments of photosynthesis  Chlorophylls & other pigments  embedded in thylakoid membrane  arranged in a “photosystem”  Collection of pigment molecules embedded in a protein

AP Biology Photosynthesis  Light reactions  light-dependent reactions  energy conversion reactions  convert solar energy to chemical energy  ATP & NADPH  Calvin cycle  light-independent reactions  sugar building reactions  uses chemical energy (ATP & NADPH) to reduce CO 2 & synthesize C 6 H 12 O 6

AP Biology 2 Processes of Photosynthesis  1) Light reactions  Takes place in the thylakoid membranes  light-dependent reactions  Uses water  energy conversion reactions  convert solar energy to chemical energy  ATP & NADPH  net products: ATP, NADPH, Oxygen  Uses photosystems with reaction centers of 2 chlorophyll-a molecules

AP Biology Light Reactions of Photosynthesis Photosystem IIPhotosystem I

AP Biology ETC of Photosynthesis  ETC uses light energy to produce  ATP & NADPH  go to Calvin cycle  PS II (PS680) absorbs light and gets excited  excited electron passes from 2 chlorophyll-a to “primary electron acceptor”  Chlorophyll is now _____________ and requires an electron  enzyme extracts electrons from H 2 O & supplies them to chlorophyll  splits H 2 O  O combines with another O to form O 2  O 2 released to atmosphere  and we breathe easier!

AP Biology Light Reactions of Photosynthesis Photosystem IIPhotosystem I

AP Biology  Excited electron passes down ETC to PS I (PS700)  Each time electron is passed, releases a little energy  used to pump H + from stroma into thylakoid  H + will then diffuse down conc. gradient back into stroma  Pass through ATP Synthase allowing phosphorylation of ADP  ATP used in Calvin Cycle

AP Biology MEANWHILE…  PS I (PS700) has also been activated by light  excited electron passes from chlorophyll to “primary electron acceptor”  need to replace electron in chlorophyll!!  Electron comes from ETC of PSII  Excited electron passes to electron carrier molecule down another ETC  Reduces NADP+ to make NADPH  Sent to Calvin Cycle in the stroma

AP Biology split H 2 O Light Reactions of Photosynthesis O ATP to Calvin Cycle H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ e e e e sun

AP Biology Photosynthesis Lab 2 Objective  Measure the rate of photosynthesis using a spectrophotometer.  Cuvette 1 should be used to calibrate the machine between each reading. Set to 100% transmittance.  Cuvette 2 should stay wrapped in foil the whole time unless a reading is being done.  Remember, DPIP changes from blue to clear as photosynthesis occurs  this will cause a higher % transmittance!

AP Biology

From Light Reactions to Calvin Cycle  Sugar Building Process  Takes place in the stroma of the chloroplast  Need products of light reactions to drive synthesis reactions  ATP  NADPH  Uses CO 2 stroma thylakoid

AP Biology RuBisCo  Enzyme which fixes carbon from air  ribulose bisphosphate carboxylase  the most important enzyme in the world!  it makes life out of air!  definitely the most abundant enzyme

AP Biology starch, sucrose, cellulose & more 1C CO 2 Calvin Cycle 5C RuBP 3C RuBisCo 1. Carbon fixation 2. G3P Production 3. Regeneration of RuBP ribulose bisphosphate ribulose bisphosphate carboxylase 6 NADP 6 NADPH 6 ADP 6 ATP 3 ADP 3 ATP used to make glucose 3C G3P glyceraldehyde-3-P CCCCCCCCCCCCCCC 6C CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC PGA phosphoglycerate CCCCCCCCCCCCCCCCCCCCC C C C 5C

AP Biology

A good scientific title!

AP Biology Photosynthesis summary  Light reactions  produced ____________  consumed ____________  produced ____________ as byproduct  Calvin cycle  consumed ____________  produced ____________  regenerated ____________

AP Biology H2OH2O Energy cycle Photosynthesis Cellular Respiration sun glucose O2O2 CO 2 plants animals, plants ATP CO 2 H2OH2O C 6 H 12 O 6 O2O2 light energy  +++CO 2 H2OH2O C 6 H 12 O 6 O2O2 ATP energy  +++

AP Biology Light Reactions O2O2 H2OH2O Energy Building Reactions ATP  produces ATP  produces NADPH  releases O 2 as a waste product sunlight H2OH2O ATP O2O2 light energy  +++ NADPH

AP Biology Calvin Cycle sugars CO 2 Sugar Building Reactions ADP  builds sugars  uses ATP & NADPH  recycles ADP & NADP  back to make more ATP & NADPH ATP NADPH NADP CO 2 C 6 H 12 O 6  +++ NADPATP + NADPHADP