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