Photosynthesis

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Photosynthesis
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Overview of Photosynthesis

• importance fix tons of CO2 per year, used as
  energy for virtually all organisms
• similarity to ETC/ox-phos, PPP and tied to gng
• 2 phases
• light-dependent rxns (light rxns)
• light-independent rxns (dark rxns)
• location chloroplast

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Detailed Chloroplast Structure

• Stroma
• thylakoid disk
• granum (grana)
• thylakoid lumen

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Light Reactions

• Antenna molecules
• chlorophyll
• carotenoids
• Special Pair
• Photosystems I and II

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Photosystem I (P700)

• Not confident all molecules have been IDd
• Major molecules
• Some of the reactions which occur
• NADPH produced

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Photosystem II (P680)

• Major molecules
• ATP produced

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Photophosphorylation

• Proton gradient develops as e are transported
• high pH inside thylakoid lumen
• protons come out through Fo of C-ATPase (CFo)
• F1 rotor forms ATP (CF1)

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Cyclic Photophosphorylation

• P700 only
• NO NADPH produced, only ATP
• Major molecules P700, Fd, Cyt. B6, Cyt f, PC

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Idealized Balanced Net Rxn
2 H2O 4 ADP 4 Pi 2 NADP
O2 4 ATP 2 NADPH 2 H
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Dark Reactions - C3 plants

• 3PG first molecule produced containing the fixed
  carbon
• rubisco- the most abundant protein in the world
• what gluconeogenic enzymes required to get Glc
  from 3PG?

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Regeneration ofRibulose-1,5-bisphosphate

• Similar to non-oxidative part of PPP

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Regeneration ofRibulose-1,5-bisphosphate
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C4 PlantsThe Hatch-Slack Pathway

• Molecular logic
• Division of labor
• Additional Rxns