Photosynthesis

• In the light-dependent reaction of photosynthesis, light energy generates ATP. Describe how. (5)

  1. Light energy excites electrons in chlorophyll
  2. Electrons pass down the electron transfer chain
  3. Electrons reduce carriers
  4. Electron transfer chain is associated with chloroplast membranes / in thylakoids
  5. Energy released / carriers at decreasing energy levels
  6. ATP generated from ADP and Pi
• Energy enters most ecosystems through the light-dependent reaction of photosynthesis. Describe

  what happens during the light-dependent reaction. (5)

  1. Chlorophyll absorbs light enrgy
  2. Excites electrons
  3. Electrons move along carriers releasing energy
  4. Energy used to join ADP and Pi to form ATP
  5. Photolysis of water produces protons, electrons and oxygen
  6. NADP reduced by electrons and protons
• Describe the role of electron transport chains in the light-dependent reactions of

  photosynthesis. (6)

  1. Electron transport chain accepts excited electrons
  2. from chlorophyll
  3. Electrons lose energy along chain
  4. ATP prduced
  5. from ADP and Pi
  6. reduced NADP formed
  7. when electrons (from transport chain) and H+ combine with NADP
• Describe how crop plants use light energy during the light-dependent reaction (5)

  1. Excites electrons
  2. Electrons move along electron transfer chain releasing energy
  3. Energy used to join ADP and Pi to form ATP
  4. Photolysis of water produces protons, electrons and oxygen
  5. NADP reduced by electrons and protons
• Describe the light-independent reactions of photosynthesis and explain how they allow the

  continued synthesis of hexose sugars. (6)

  1. RuBP (5C) combines with CO2
  2. to form 3C compound
  3. using ATP
  4. and reduced NADP
  5. 2 molecules of 3C compound (TP) form hexose
  6. all RuBP is regenerated
  7. 10 molecules of 3C form 6 molecules of 5C
• Describe the light-independent reaction of photosynthesis. (6)

  1. Carbon dioxide combines with RuBP
  2. Produces two GP using Rubisco
  3. GP reduced to triose phosphate
  4. using reduced NADP
  5. Using energy from ATP
  6. Triose phosphate converted to glucose and RuBP
• During the light-independent reaction of photosynthesis, carbon dioxide is converted into organic

  substances. Describe how. (6)

  1. Carbon dioxide combines with RuBP
  2. Produces two GP
  3. GP reduced to triose phosphate
  4. Using reduced NADP
  5. Using energy from ATP
  6. TP converted to glucose and RuBP
• In the light-independent reaction of photosynthesis, the carbon in carbon dioxide becomes carbon in

  triose phosphate. Describe how. (5)

  1. Carbon dioxide combines with RuBP
  2. To produce two molecules of GP
  3. Reduced to triose phosphate
  4. Requires reduced NADP
  5. Energy from ATP
• During photosynthesis, oil-palm trees convert carbon dioxide into organic substances. Describe

  how. (6)

  1. Carbon dioxide combines with RuBP
  2. Produces two molecules of GP
  3. Reduced to triose phosphate
  4. Using reduced NADP
  5. Usign energy from ATP
  6. TP converted to organic substances.
  7. In light independent reaction