light dependant reaction

• reduction

  • gain of electrons(-)
  • gain of hydrogens(+)
• oxidation

  • loss of electrons (-)
  • loss of hydrogens(+)
• reactants

  • water
  • NADP
  • ADP+PI
• products

  • oxygen
  • reduced NADP
  • ATP
• role of NADP

  • NADP can REDUCE molecules by giving away hydrogen(NADP is oxidised)
  • NADP can OXIDISE molecules by recieving hydrogen(NADP is reduced)
• photolysis

  light breaks H20= O , 2H+ and 2E-
• describe the light dependant reaction(MARK SCHEME ANSWER)

  • photolysis occurs to split water into oxygen,hydrogen ions and electrons (1)
  • use of light energy to excite electrons in chlorophyll- electrons promotes to higher energy level (1)
  • electrons then used in the electron transport chain (1)
  • this generates ATP and NADP is reduced (1)
• detailed stages of light dependant reaction

  • light energy hits photosystem 2 in thylakoid membrane
  • 2e- gain energy and are excited to a higher energy level
  • accepted by electron acceptor in ETC
  • energy is released when passing down ETC in a series of redox reactions- energy used in photophosphorylation(ADP+PI=ATP)
  • electrons now at photosystem 1, light excites them, accepted by electron acceptor, pass down ETC
  • these electrons combine with H+ ions (from photolysis of water) and NADP= reduced NADP
• ATP and reduced NADP then passed onto the light Independent stage
• where does light dependant stage occur?

  • in the thylakoid membranes/thylakoid/grana