Chapter 6 Capturing Solar Energy: Photosynthesis

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Chapter 6Capturing Solar Energy
Photosynthesis
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Thylakoid Structure Light-Dependent Reactions
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Light Independent Reaction/ Calvin Cycle (occurs
in Stroma)

• ATP and NADPH from the light dependent reaction
  provides Energy to power the synthesis of glucose
  from CO2 and water
• This process occurs independent of light as long
  as ATP and NADPH are present

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Calvin Cycle

• Calvin Cycle Requires
• CO2
• CO2 Capturing Sugar called RuBP a 5 carbon
  sugar
• Enzymes to catalyze all reactions
• Energy from ATP and NADPH (produced in light rxn)

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Calvin Cycle is a - Three Step Cycle

1. Carbon Fixation
2. Synthesis of G3P
3. Regeneration of RuBP

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Calvin Cycle Steps

• Carbon Fixation
• Begins and ends with 6 RUBP a 5 Carbon sugar
• Enzymes combine 6 RUBP molecules with 6CO2 from
  atmosphere to form 12 (3 carbon molecules of PGA)

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Calvin Cycle Steps

• 2. Synthesis of G3P
• Energy donated by ATP and NADPH is used to
  convert PGA to G3P

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Calvin Cycle Steps

• 3. Regeneration of RuBP
• ATP is used to turn G3P into RUBP which is used
  at the start of carbon fixation
• Remaining G3P molecules will be used to synthesis
  glucose

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Summary of Calvin Cycle light Independent
Reaction

• 6 molecules of CO2 captured by 6 molecules of
  RuBP
• ATP and NADPH drive production of 12 molecules of
  G3P
• 2 G3P used to make glucose
• ATP generates 6 RuBP molecules from 10 molecules
  of G3P

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Overview of Photosynthesis
Light-DependentReactions(in thylakoids)
O2
H2O
DepletedCarriers(ADP, NADP)
EnergizedCarriers(ATP, NADPH)
Light-IndependentReactions(in stroma)
Glucose
CO2H2O
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A Summary of Photosynthesis
Light-dependent reactions occur in thylakoids
Light-independent reactions (c3 cycle) occur in
stroma
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The End of PhotosynthesisChapter 8