non-cyclic photophosphorylation

• what is the first step of non cyclic photophosphorylation


  the photons of light energy are absorbed by photosystem 11 and passes to chlorophyll a in the reaction centre
• what happens in non-cyclic photophosphorylation after the light energy reaches the reaction centre


  the light energy excites chlorophyll a and two electrons are released and raised to a higher energy level where they are passed to an electron acceptor
• what happens in non-cyclic photophosphorylation when the excited electrons reach the electron acceptor after ps11


  the electrons pass along a chain of carriers and through proton pumps to reach ps1
• what happens in non-cyclic photophosphorylation what happens as the electrons are passed from carrier to carrier in the chain to ps1


  their energy levels decrease
• when electrons are losing energy as they are passed from carrier to carrier what happens to the energy lost


  it is used to provide energy to proton pumps to pump protons(hydrogen ions) from the stroma across the thylakoid membrane to the thylakoid space
• describe how protons are transported across the thylakoid membrane


  energy from the electrons fuel the proton pumps to pump protons from the stroma across the thylakoid membrane and into the thylakoid space
• how many electrons area exited at ps11


  2
• in non-cyclic photophosphorylation what does the movement of protons from the stroma to the thylakoid space cause


  the production of a electrochemical gradient
• what will happen to the concentration of H+ ions in the stroma when they are moved across the thylakoid membrane into the thylakoid space


  it will decrease
• what happens to the protons in the thylakoid space


  they will pass down the chain until they reach a stalked particle where they will provide the energy for photophosphorylation
• what happens during photophosphorylation


  the formation of ATP from ADP and PI
• what enzyme is found in the stalked particle


  ATP synthase
• what happens in non-cyclic photophosphorylation when the electrons have reached photosystem 1


  the protons will be raised to a high energy level where they will be picked up by another an electron acceptor
• what happens in non-cyclic photophosphorylation what happens to the electrons when they have reached the electron acceptor after ps1


  they are passed to hydrogen ions outside of the thylakoid membrane into the stroma where they reduce NADP to reduced NADP
• what does the reduction of NADP require


  protons
• what does the reduction of NADP cause in the stroma


  a decrease in the concentration of protons
• how is the electrochemical gradient maintained


  the protons are brought into the thylakoid space and are removed by the reduction of NADP
• why is the process called non-cyclic photophosphorylation


  this is because the electrons are not recycled back
• what effect will higher concentration of H+ ions have on the thylakoid cavity


  a lower ph