Transcript Photosynthesis

Photosynthesis
What is it?
• Photo – light
• Synthesis – to make
• The process of converting light energy to
chemical energy and storing it as sugar.
The Equation
CO2 + H20  C6H12O6 + O2
Where does it occur?
• In the Chloroplasts
– Chloroplasts contain chlorophyll (pigment) that
give plants their green color
Parts of Photosynthesis
• Light Reactions
– Takes place in the Thylakoid Membrane
• Use – Light, Water
• Produce – Oxygen, NADPH, ATP
• Calvin Cycle (Dark Reactions)
– Takes place in the Stroma
• Use – CO2, NADPH, ATP
• Produce - Sugar
The Light Reactions
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In the Thylakoid Membrane
Require direct light
Use – H2O
Produce – O2, NADPH, ATP
Electron Transport Chain
The Light Reactions
• Steps
– Light strikes photosystem
• Photosystem – collection of pigments
– Electron becomes “excited” and moves through
the electron transport chain
– H2O replaces electron and breaks into H+ and O
• O + O = O2
– Electron movement allows for ATP to be made
– NADP + accepts electron and joins with H+ to
make NADPH
The Calvin Cycle
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In the Stroma
Do not require direct light
Use - CO2, NADPH, ATP
Produce - Sugar
Cycle - continuous
The Calvin Cycle
• Steps
– Carbon Fixation
• CO2 goes into the cycle and is “fixed” to become sugar
by Rubisco
– Most important enzyme on earth
– Reduction
• ATP and NADPH go into cycle
• Sugar is produced
– Regeneration
• Rubisco is regenerated to accept more CO2