Chloroplast pigments

• Chloroplasts contain several different photosynthetic pigments within the thylakoids, which absorb different wavelengths of light.
• in palces, thylakoids stack up to form structures known as grana
• the thylakoid membrane system provides a large number of pigment molecules in arrangement that ensures as much light as necessary is absorbed
• pigment molecules are arranged in a light-harvesting clusters known as photosystems
• In photosystem 2, the pigments are arranged in a funnel-like structure in thylakoid membrane (each passes energy down to next pigment molecule, until reaches pigment reaction centre)
• light dependant stage occurs in thylakoid membrane and spaces
• this is why thylakoid membrane contains pigments, enzymes and electron carriers required for light dependent stage
• Chlorophyll

  • absorbed wavelengths in blue-violet and red regions of light spectrum
  • Reflect green light (hence plants are green)
• Carotenoids

  1. absorb wavelengths of light mainly in blue-violet region of spectrum
• pigments themselves have colours, which are colours of the visable light spectrum they reflect. Different from colours they absorb