Linear Electron Flow II

• Results


  Photophosphorylation
• 5th step

  • As e- are passing through the cytochrome complex in ETC, it's creating H+ which are pumped into thylakoid space
  • This creates H+ gradient
  • Causes chemiosmosis
  • ATP formation
• 6th Step

  • Light also hits PSI reaction center complex, not just PSII
  • energy coming from light causes excitation at PSI simultaneously
  • excites e- within P700
  • excited e- must be transferred to primary electron acceptor
  • P700 lost e-, oxidized to P700+
  • fix this by using e- from P680 to fill void
• 7th Step

  • PSI e- passed down a DIFFERENT ETC until accepted by feredoxin (Fd) (final e- acceptor in this situation, protein w/ iron)
  • NO H+ GRADIENT FORMING
  • NO ATP from PSI e- ETC
• 8th Step

  • 2 e- from ferredoxin get passed to NADP+ (oxidized state so it becomes oxidizing agent)
  • NADP+ turned into NADPH
  • catalyzed by NADP reductase
  • NADPH transported into stroma because it will be used with ATP in Carbon fixation rxns
• Terminal e- acceptor (LEF) 


  NADP+ ---> NADPH via NADP+ reductase

  NADP+ is the terminal e- acceptor
• H+ pumped from stroma to thylakoid lumen


  stroma (Highly acidic as all H+ pumped out into stroma) back to thylakoid lumen via ATP synthase
• After LEF, ATP + NADPH is produced, released into stroma for CFN rxns