Photosynthesis
Light-Dependent Reactions | The Calvin Cycle
Photosynthesis
Learning Objectives
• List the major events of photosynthesis
• Describe the light-dependent reactions of photosynthesis
• Explain how matter cycles within the Calvin cycle
Light-Dependent Reactions
• Photosynthesis occurs in the chloroplast
• Chloroplast structure
– Stroma – the fluid interior of a chloroplast
– Thylakoid – the interconnected disk-shaped pouches in
chloroplast
– Granum – a group of thylakoids
Light-Dependent Reactions
• Photosynthesis consists of two processes: the lightdependent reactions and the light-independent reactions
Light-Dependent Reactions
• Light-dependent
reactions
– Energy from the sun
creates ATP and
NADPH to be used in
the light-independent
reactions
Light-Dependent Reactions
• Light-dependent reactions are similar to a Rube Goldberg
machine
Light-Dependent Reactions
The Calvin Cycle
• Light-independent
reactions use stored
energy
• Calvin cycle – the
series of steps during
the light-independent
reaction of photosynthesis in
which a three-carbon sugar is
formed
1. Carbon fixation
2. Reduction
3. Regeneration
The Calvin Cycle
• Calvin cycle
1. Carbon fixation
The Calvin Cycle
• Calvin cycle
1. Carbon fixation
2. Reduction
The Calvin Cycle
• Calvin cycle
1. Carbon fixation
2. Reduction
3. Regeneration
Overview
Overview
Light-dependent reactions versus light-independent reactions
Light-Dependent
Reactions
Light-Independent
Reactions
Location
Thylakoid membrane
Stroma
Reactants
Water
Carbon dioxide
Product
Oxygen
Sugar
ATP produced and NADP ATP used to yield ADP
Carriers
and NADPH oxidized to
energized/reduced reduced to NADPH
+
NADP
Sunlight required? Yes
No
Photosynthesis
Learning Objectives
• List the major events of photosynthesis
• Describe the light-dependent reactions of photosynthesis
• Explain how matter cycles within the Calvin cycle