Photosynthesis

• what is the formula for photosynthesis?

  carbon dioxide + water - oxygen + glucose
• what coenzyme is involved in photosynthesis? what does it do ...

  NADP. it transfers hydrogen from one molecule to another. (either reduced/oxidised)
• what is the structure of a chloroplast?

  structure:

  A) outer membrane envelope

  B) inner membrane envelope

  C) granum

  D) lamella

  E) DNA

  F) starch grains

  G) stroma

  H) thylakoid

  I) ribosomes

  
• what photosynthetic pigments do chloroplasts contain?

  chlorophyll a

  chlorophyll b

  carotene
• what are primary pigments?

  are reaction centres (where electrons are excited during the light dependent reaction)
• what are accessory pigments?

  make up light-harvesting systems (they transfer energy to the primary pigments)
• what wavelength does photosystem 1 absorbed light best at?

  700nm
• what wavelength does photosystem 2 absorbed light best at?

  680nm
• Describe the stages in the light-dependent reaction.

  • Light energy excites electrons in chlorophyll - PS2, electrons move down electron transport chain to PS1.
  • Photolysis of water produces proton/electron/oxygen - to replace others.
  • electrons lose energy as they move down ETC. This energy moves protons via proton pumps into thylakoid. Via ATP synthase protons move down conc gradient into stroma. ADP +P - ATP.
  • light energy is absorbed by PS1, further exciting the electrons. Electrons with proton form reduced NADP.
• Describe the stages of the Light-Independent stage (Calvin Cycle).

  • CO2 + RuBP forms 3 carbon GP, catalyzed by RuBisCO.
  • ATP and reduced NADP are required for the reduction of GP to TP.
  • TP is converted into many useful organic molecules (glucose)
  • 5/6 TP are used to regenerate RuBP. Rest of ATP from Light d stage used here.
• Where does the Calvin cycle take place?

  Stroma
• what are the limiting factors for photosynthesis?

  Light intensity - more light, more energy.

  Temperature - enzymes involved/stomatal closure at high temp, less CO2 enters, reduces photosynthesis/thylakoid membrane damage/ chlorophyll damage.

  Carbon dioxide concentration - more CO2, faster rate. but if too high stomata close.