🎵 Luyện Nghe Bài Hát: Photosynthesis - The Light Reactions - Glenn Wolkenfeld

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