🎵 Luyện Nghe Bài Hát: Photosynthesis - Glenn Wolkenfeld

 Photosynthesis
 Non Cyclic Electron Flow  The Calvin Cycle
  Lecture by Glenn Wolkenfeld
 
 Thanks for joining us for Episode 
 Wher more  photosynthesic waits for you.
 We last saw how plant cells create, O¬¬2, ATP,  NADPH.
 Now we’ll start with a twist on the  reactions,
 Called cyclic flow, we’ll see  it happens.
 Then  will investigate how the Calvin Cycle makes carbohydrate.
 
 (Part  Cyclic Electron Flow)
 Non – cyclic flow is also  the “Z – scheme” Put Z on its site and see what I mean.
 Electrons rise in energy then  and rise again.
 Making ATP  NADPH my friends.
 A variation on this is  flow.
 Which makes  no NADPH or O.
 Cyclic flow results from the Calvin Cycle’s 
 It  less NADPH than ATP.
 NADPH buildup has the repercussion, of  NADP+ reduction.
  NADPH clogs up reductase.
 Keepping NADP+  moving into place.
 So electrons don’t  to NADP+.
  clogged, stuck like a pimple’s pus.
  can they go from P700?
 Nature evolved them a place  flow.
 A shunt pathway moves them to  ETC.
 I’m talking ‘bout the one in PS II tou 
 These  alectrons flow and release energy.
 Which as you  is used to synthesize ATP.
 
 ( Part  Calvin Cycle)
 Now it’s time to learn the  named for Calvin.
 Which results in the  of carbon.
 Consider that each carbon in your bones,  and hair,
 Was  in a CO2 in the air.
 The Calvin  has three parts.
 Fixation of carbon is  it starts.
  molecules produced rae then reduced.
 ‘cause reduction  the key thing that happens in part 2.
 Part 2 is the payoff as  will see.
 It  molecule G3P
 A  molecule with lots of energy.
 And  starting point for all the molecules that cells need.
  3 sets up conditions for the cycle’s start.
  recreating what’s at the cycle’s heart.
 RuBP (Ribulose  a five carbon molecule that seems to apparate.
 ‘Cause RuBP’s at the  start.
 Then reappears at the very last 
 The role of RuBP at the start and 
 Is why this is  cycle like the one named Krebs.
 The cycle’s inputs are know to  NADPH and ATP and CO2
 Fixation  carbon is catalyzed by RuBP Carboxylase Enzyme
  enzyme’s nickname you should know.
 Sounds like a  maker: it’s RUBISCO.
 An enzyme  old it was already here,
 Before O2 accumulated in the 
  CO2 enters through leaf stoma, diffusing through the leaf and arriving at the stroma.
 There RuBisCO grabs it in its active site, and squeezes it  RuBP tight.
 RuBP has carbons five, it has two phosphates, one on  side.
 When CO2 combines with RuBP it makes a six carbon compound  won’t see.
 It instantly  into two 3 – phosphoglycerates,
 Each  three carbons and one phosphate.
 Each gets phosphorylated  bisphosohoglycerate.
 Phosohorylated means that each receives aphosphate group from 
 This phospharylation,  followed by reduction.
 And you know there’s an enzyme with  function.
 Of taking electrons and H from NADPH  adding them to to bisphosphoglycerate.
 Take off  phosphate for Glycealdehyde – Phosphate.
 A  point for compounds like carbohydrates.
 
 (Part III: Calvin Cycle, 
 Glyceraldehyde- 3 –  known as G3P,
 as a product cells harvest, and I hope  see,
 how  reactions NADPH and ATP,
 are needed to fix  and make organic energy.
 And to complete  cycle we must now regenerate.
 The starting point  Calvin Cycle ribulose bisphosphate.
  intermediates involved in taking G3Ps,
 And recombining them  RuBPs.
 Are too  for freshman biology.
  can get the details when you get yors Ph. D.
 But know for now that to  3 RuBPs from 5 G3Ps cost 3 ATPs!
 
 (Part  Conclusion)
 Now this journey ends whit its 
 On the  of photosynthesis.
 For over four billion years it’s  the food chains basis.
 In fossils from that era you can  the traces,
  tiny cells with prokaryotic form.
 Stromatolites that lived in  warm.
 Through photosynthesis they transformed  planet,
 So  life can live upon it.
 And so evolved sentient beings who  analyze,
 How photoautotrophs can 
 You could say that photosynthesis gave birth  codiyions for cons ciousness on Planet Earth!