L6. Photosynthesis 1

• What is the process of photosynthesis primarily converting?

  Atmospheric CO2 and H2O to carbohydrates
• How is solar energy captured in photosynthesis?

  As ATP and NADPH

  
• What do phototrophs do in photosynthesis?

  They are photosynthetic organisms
• What are the two types of reactions in photosynthesis?

  • Light reactions (light-dependent)
  • Dark reactions (light-independent)

  
• What do light-dependent reactions release from water?

  O2 from splitting 2H2O molecules
• What is the role of H+ from H2O in light reactions?

  Used in the Chemiosmotic synthesis of ATP
• Where do dark reactions occur?

  In solution
• What do dark reactions require for carbohydrate synthesis?

  Energy from NADPH and ATP
• What is the structure of chloroplasts?

  • 4-8 mm diameter organelle
  • Two surrounding membranes
  • Internal membrane stacking

  
• What is the main pigment involved in light harvesting?

  Chlorophyll
• What is the structure of chlorophyll?

  Contains a tetrapyrrole ring with Mg2+
• What are the two types of chlorophyll in plants?

  Chlorophyll a and b
• What do antenna pigments do in photosynthesis?

  Extend the range of light capture
• How do antenna pigments and chlorophylls interact?

  They exchange light energy until captured
• What are the two Photosystems involved in light absorption?

  • Photosystem I (PSI)
  • Photosystem II (PSII)

  
• What is the maximum light absorption wavelength for PSI?

  700 nm
• What is the maximum light absorption wavelength for PSII?

  680 nm
• What does the Z-scheme represent in photosynthesis?

  Path of electron flow and reduction potentials

  
• What happens to P680 and P700 when light energy is absorbed?

  They become excited molecules
• What is produced when 2 H2O are oxidized?

  2 NADPH are reduced
• What drives the electron flow in the Z-scheme?

  Light energy
• What is the role of DµH in photosynthesis?

  Drives protons through ATP synthase

  
• What is photophosphorylation?

  Synthesis of ATP dependent on light energy

  
• What are the two major particles of chloroplast ATP synthase?

  CFo and CF1
• What does CFo do in ATP synthesis?

  Forms a pore for H+
• What does CF1 do in ATP synthesis?

  Catalyzes ATP synthesis from ADP and Pi

  
• How many ATP are produced for every 2 NADPH generated?

  2 ATP are produced
• What is required for each CO2 reduced to carbohydrate?

  2 NADPH and 3 ATP
• What does cyclic electron transport yield?

  ATP but not NADPH

  
• What increases ATP production in cyclic electron flow?

  Proton motive force

  
• What is the summary of photosynthesis light reactions?

  • Uses light energy to fix carbon into sugar
  • Drives photosynthetic electron transport to generate µH
  • Reduces NADP and phosphorylates ADP
  • Takes place in the chloroplast