Chloroplasts

• Chloroplast envelope

  Double plasma membrane, highly selective on what enters and exits
• Grana/granum


  stacks of up to 100 thylakoids where light absorption takes place
• Thylakoids


  Contain chlorophyll, some have tubular extensions that join up with thylakoids in adjacent grana.
• Stroma

  Fluid filled matrix, site of the second stage of photosynthesis takes place, other structures such as starch grains are within the stroma
• Why do granal membranes have a large surface area?

  For the attachment of chlorophyll, electron carriers and enzymes that carry out the first stage of photosynthesis
• Why do chloroplasts contain DNA and ribosomes?

  To quickly and easily manufacture some of the proteins needed for photosynthesis.
• CHLOROPLAST DIAGRAM