structures within a leaf for photosynthesis

• Define chemoautotrophs

  Synthesise complex organic molecules using energy from chemical reactions
• Define autotroph

  Organisms that use light energy/chemical energy and inorganic molecules (water and carbon dioxide) to synthesise complex organic molecules (glucose) -eg plants
• Define heterotroph

  Ingest and digest complex organic molecules, releasing chemical potential energy stored in them (mammals, humans)
• What is the primary pigment in plants?

  Chlorophyll A
• State all the photosynthetic pigments

  • Chlorophyll A
  • Chlorophyll B
  • Xanthophylls
  • Carotenoids
  • Form antennae complex
• What is an absorption spectrum?

  shows wavelengths which are best absorbed
• What is an action spectrum?

  Shows effectiveness of wavelengths absorbed
• What organic molecule produced from photosynthesis do chloroplasts store?

  Starch
• what is the purpose of the process of photosynthesis?

  light from the sun is harvested and used to drive the production of chemicals like ATP, and to synthesize large organic molecules from inorganic ones
• what is light energy used for in plants?

  to drive the synthesis of carbon dioxide and water from glucose
• true or false? chloroplasts contain DNA

  TRUE
• State all the structures, functions and adaptations within a chloroplasts and how this helps a plant to photosynthesise effectively

  • outer membrane
  • inner membrane with transport proteins- regulates entry and exit of substances, facilitated diffusion of ions, helps diffusion to happen at a faster rate
  • MANY grana- large SA for photosynthetic pigments to absorb maximum amount of light
  • photosynthetic pigments- help to absorb light at a variety of wavelengths
  • proteins embedded in the grana- holds photosystems in place
  • stroma- contains enzymes for light independent reactions- site of chemical reactions
  • DNA and ribosomes- for protein synthesis
  • thylakoid membranes- large network to increase SA and maximise absorption
  • intergranal and granal lamellae
  • starch grains- store excess carbs made in photosynthesis

  
• why do different photosynthetic pigments have different wavelengths?

  they absorb and reflect different wavelengths of light
• describe the structure of chlorophyll

  • porphoryn ring (hydrophyllic)
  • lipid soluble tail (hydrophobic)
• what is an antennae complex?

  • made up of different photosynthetic pigments
  • purpose is to maximise absorption of light
  • accessory pigments on the outside- harvest light energy of different wavelengths and transfer it quickly and efficiently to the reaction centre (which contains chlorophyll A)
  • the reactions involved in photosynthesis take place at the reaction centre
  • this is collectively known as a photosystem
• what is photosystems 1 and 2 (antennae complexes) and what is the difference between them?

  • photosystem 1 has a chlorophyll molecule that absorbs light of wavelength 700nm and is mainly found on inter-granal lamellae
  • photosystem 2 has a chlorophyll molecule that absorbs light of wavelength 680 nm and is mainly found on granal lamellae
• which pigment in an antennae complex has a lower energy of excitation?

  the one at the centre (chlorophyll A)
• of the colours of the rainbow, which has the longest and shortest wavelength, therefore have the greatest and least greatest energy of light?

  • red = longest, least energy
  • violet = shortest, most energy