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 Photosynthesis : part  - The Light Reactions
 Amusical Lecture by Glenn 
 
 A music  by Glenn Wolkenfeld
 Boys and girls  me what you think of this,
 Time for a lesson ‘bout 
 Cells use light  combine water carbon dioxide.
 Gonna see electrons going  a wild ride.
 Making sugar, making sweet 
 But why should  matter to you?
  on your table.
 O2 rich atmosphere.
 Without photosynthesis  simple wouldn’d be here.
 
 ( Part I, The  Picture)
 Photosynthesis is a redox 
 Powered by light using enzymatic 
  oxidized, CO2’s re duced
 The sugar  results you drink in orange juice.
 The overall reaction has  phases.
  is the light reactions which has as its basis.
 Light powered production of 
 O2 is the by – product and you  see.
  of electron carrier NADPH
 Which provides reducing power needed  the second phase
 ‘Cause NADPH, during phase 
  what’s needed for reducing CO2
 NADPH ia  by a reduction of NADP+, whose function
 Is to absorb electrons and pick up 
 Gaining energy and making 
 Phase 2 is the Calvin Cycle  carbohydrate,
  sugar and starches and fibers on your lunch plate.
  how plants make food animals eat.
 Photosynthesis, it’s so 
 
 (Part  Chloroplasts, Thylakoids, Light, and Chlorophyll)
 In  lesf there’s mesophyllic tissue
 And cells with chloroplasts  to the issue.
 Chloroplasts are almost like cells  every way,
 With their own  and their own DNA.
 They even reproduce themselves,  into half.
 A clue for this  independent past.
 This theory has a name 
 Developed  the 60s by Lynn Margulis.
  the chloroplast is the fluid stroma.
 It’s true  Tokyo.
 It’s  in Roma.
 Stroma syrrounds little 
 Each one has  hollow space inside.
 The  membrane is loaded with protein.
 ‘Cause it’s  light reactions’ scene.
 It’s all about using light for powering 
 All about  the power in photons.
 The photons needed  are those from light,
 Which has the energy to make the  bright.
 The highest frequency that  can see,
 Is  light with wavelength 380.
  nanometers, sounds small,
 But next to gamma rays it’s  tall.
 Red light  at 750.
  the visible spectrum nifty?
 Photons are packets of light 
 Both a wave and  particle, you see.
 Phootins get adsorbed  pigments.
  real, it’s true, it ain’t no figment!
 Most important  green chlorophylls.
 Orange carotenoids, and yellow 
 Together they absorb light,  red and blue.
 The green is not absorbed it  back to you.
 In chlorophyll see  porphyrin ring.
 See  magnesium, which makes you want to sing,
 Magnesium, metal  valence two.
  see those electrons rocketing through.
 Notice  tail, a hydrocarbon chain.
 Which anchors chlorophyll  the thylakoid membrane.
  molecule with style, so pretty,
 In the thylakoid it makes 
 
 ( Part III)
 Englemann showed us  action spectrum.
 Used  prism to break the sun’s
 Light  its frequencies.
  it on spirogyra, filamentous algae.
 The O2  make will stimulate bacteria.
  will grow in any oxygen – rich area.
 Bacteria loved  over blue and red,
 But hardly  over green, they might as well be dead!
 The line of growth  a refection, of photosynthesis’ action spectrum.
 Note this  match, exactly,
 The absorption spectra  chlorophyll a or b.
 ‘Cause the cartenoids  xanthophylls we’ve met,
 Absorb light frequencies  chlorophylls can’t get.
  in the thylakoid they all cooperate,
 In using light to  carbohydrate.
 Consider chlorophyll in 
 Shine some light upon it (call it 
 The  electrons in magnessium
 Jump to an excited state,  so fun!
 But once up at that level,  can only fall.
 Back to where they  like a bouncing ball.
 These falling alectrons, release 
 Fluorescing as red light, as  can see.
 But  thylakoids, chlorophyll’s not alone,
 Instesd a photosystem is  home.
 The  parts can take photons,
  use their energy to move electrons.
 The system’s antenna complex does the  capture,
 Changing photon anergy into electron 
 The energized electrons bounce  a ball,
 At the reaction center, they jump but do not 
 A  electron acceotor grabs them from on top,
  yanks them with a force reaction center cannot stop.
 To  oxidized reaction center we’ll return,
 But the details  electron flow it now is time to learn.
 
 ( Part IV) ATP Synthesis in Non –  Electron Flow.
 Non -  cycle flow  the main pathway.
 Much confustion relates to  way
 Hootoystm II precedes  I.
 It’s  fct to memorize, just get it done!
 PS II’s antenna captures  photon,
 Generates a flow of 
 All around the world, even  Haiti,
 They flow to reaction center 
 There  do not hover,
 Electron  passes them over.
 To the electron transport 
 In the thylakoid 
 This chain’s like a bucket 
 Each molecule has  similar trade.
 They take  electrons,
 And use their  for pumping protons.
  stroma to the thylakoid space.
 Packing protons  that place.
 This makes a  across the thylkoid membrane
 The protons  “out” or they’ll go insane.
  the protons can’t permeate.
 The membrane won’t allow 
 There’s only one port through which  travel.
 It’s the ATP  channel.
 The “-ase” tells you this is  enzyme.
 Which makes ATP  the time.
 It has binding sites  ADP and Pi,
 And channels for diffusing protons whose knetic 
 Changes the binding sites’ 
 Fusing ADP with Pi which  your information.
 Is  thylakoids make ATP.
 Life’s key form  energy.
  respiration this might feel familiar.
 ATP is  this way in mitochondria.
 Chemiosomosis is the 
 ATP  is the game.
 
 ( Part V: NADPH Synthesis  Non – Cyclic Elecron Flow)
 Back to our electons moved by  sun.
 Flowing from Photosystem II  System I.
 They get to PS I lke a  up battery.
 The transport chain used  their energy.
 But when light hits  I’s antenna
 Electrons boune  reaction center.
 This one’s P700,
 That wavelength makes electrons 
 PS T’s  acceptor grabs them away,
 Leaving  in an oxidized way.
 And P700 with its oxidized blues accepts the alectrons from  II.
 Bak to electron from PS 
 It now gose for a ride,  its own fun.
 But powering proton pumps ain’t  fate.
 It travels to NADP+ 
 An enzyme  cells count upon.
 To pass some H and 
 To NADP+  gets reduced.
 It’s how NADPH get 
 
 (Part VI: Oxygen Production  Non – Cycli Electron Flow)
 The by – product of  light reactions
  oxygen here’s how it happens.
  PS II, it came to arise,
 That  got oxidized
 To replace lost electrons P680 
 Electrons from  which dissociates.
  one oxygen and protons two,
 The single O will meet anoher forming 
  protons are formed in the thylakoid space.
 Increasing proton concentration  that place.
 So we see a side effect  water’s oxidation.
  enhancement of ATP creation.