L6 chloroplasts

• photoautotrophs

  organisms that can make their own energy using light and carbon dioxide (photosynthesis)
• chloroplast structure:

  • inner and outer membrane (envelope)
  • stroma (inside the inner membrane) where granules are found
  • granules are made of thylakoid stacks
  • chlorophyll is found in the thylakoid membrane
• light reactions occurs in the

  thylakoid
• the Calvin cycle occurs in the

  stroma
• Calvin cycle can happen in the dark in the _

  stroma
• longer wavelength of light= _ energy

  lower
• excitation of isolated chlorophyll:

  • photon hits chlorophyll molecule
  • energy from light excites electron to higher energy state
  • electron falls back to ground state if no other pigment nearby
  • energy released as heat or fluorescence
• chlorophyll pigments close together so energy isn't lost

  primary electron acceptor accepts electrons from higher energy state
• what are the photosystems in the light reaction called?

  photosystem I (p700) and photosystem II (p680)
• non-cyclic electron flow:

  • PSII splits water
  • electrons replace those lost by p680
  • generates O2 and H+
  • ATP synthase uses H+ gradient to generate ATP
  • across the thylakoid membrane as water split in thylakoid space due to electron transport chain activity
• cyclic electron flow only uses _

  photosystem I
• cyclic electron flow:

  1. electrons passed from primary electron acceptor through chain
  2. chain includes ferredoxin, cytochromes and copper containing protein (plastocyanin)
  3. electron then passed back to P700
  4. energy lost at each step, which is then used to pump hydrogen ions across the thylakoid membrane
  5. drives the ATP synthase to generate ATP
  6. cycle doesn't produce NADPH or oxygen
• Calvin cycle turns carbon from carbon dioxide to a sugar
• Calvin cycle requires ATP as energy and consumes NADPH as source of high energy _


  electrons
• hexose phosphates generated in the Calvin cycle for storage, cell walls, translocation, cell membranes and protein synthesis:


  starch, cellulose, sucrose, lipids and amino acids
• rubisco used for carbon _

  fixation
• phase 2 of Calvin cycle is to _ carbon chain

  reduce
• phase 3 of the carbon cycle is to _

  regenerate CO2 acceptor (RuBP)
• light reaction products are requires for the _

  Calvin cycle
• similarities between chloroplasts and mitochondria:

  • electron transport chain to pump hydrogen ions
  • ATP synthase complex to phosphorylate ADP to ATP
  • double membranes
  • similar endosymbiotic origin
• differences between mitochondria and chloroplasts:

  • source of these high energy electrons (M=organic molecules, C=splitting water)
• green plants are not the only organisms to have chloroplasts:

  e.g. cyanobacteria, algae
• chloroplast thylakoid membrane contains _ molecules

  pigment
• thylakoids are the site of the _


  light reactions
• cyclic electron transport involves

  photosystem I
• plant cells have _ and _

  chloroplasts and mitochondria