8.1
What Is Photosynthesis? 161
Photosynthesis involves two pathways
162
8.2
How Does Photosynthesis Convert Light
Energy into Chemical Energy? 163
Light behaves as both a particle and
a wave 163
Absorbing a photon excites a pigment
molecule 163
Absorbed wavelengths correlate with
biological activity 163
Photosynthesis uses energy absorbed
by several pigments 164
Light absorption results in photochemical
change 165
Excited chlorophyll in the reaction
center acts as a reducing agent 166
Reduction leads to electron transport
166
Noncyclic electron transport produces
ATP and NADPH 166
Cyclic electron transport produces
ATP but no NADPH 168
Chemiosmosis is the source of the
ATP produced in photophosphorylation
168
8.3
How Is Chemical Energy Used to Synthesize
Carbohydrates? 169
Radioisotope labeling experiments
revealed the steps of the Calvin cycle
169
The Calvin cycle is made up of three
processes 170
Light stimulates the Calvin cycle
172
8.4 How Do Plants Adapt to the Inefficiencies
of Photosynthesis? 172
Rubisco catalyzes RuBP reaction with
O2 as well as with CO2 172
C4 plants can bypass photorespiration
173
CAM plants also use PEP carboxylase
175
8.5
How Is Photosynthesis Connected to
Other Metabolic Pathways in Plants?
175
