Incorporating co 2 into organic acids stomata close

incorporating CO
2
into organic acids
• Stomata close during the day, and CO
2
is
released from organic acids and used in
the Calvin cycle
Light
Light
Reactions:
Photosystem II
Electron transport chain
NADP 
ADP
+ P
i
RuBP
3-Phosphoglycerate
Calvin
H
2
O CO
2
Figure 10.22
Photosystem I
Electron transport chain
ATP
NADPH
Cycle
G3P
Starch
(storage)
Sucrose (export)
Chloroplast
O
2

10
The Importance of Photosynthesis
• The energy entering chloroplasts as sunlight
gets stored as chemical energy in organic
compounds
• Sugar made in the chloroplasts supplies
chemical energy and carbon skeletons to chemical energy and carbon skeletons to
synthesize the organic molecules of cells
• Plants store excess sugar as starch in structures
such as roots, tubers, seeds, and fruits
• In addition to food production, photosynthesis
produces the O
2
in our atmosphere
You should now be able to:
1. Describe the structure of a chloroplast
2. Describe the relationship between an
action spectrum and an absorption
spectrum
3. What is non cyclic flow of electrons and
its importance
4. What is cyclic flow of electrons and its
importance
5. Describe the similarities and differences
between oxidative phosphorylation in
mitochondria and photophosphorylation in
chloroplasts
6 Describe the role of ATP and NADPH in the 6. Describe the role of ATP and NADPH in the
Calvin cycle
7. Describe the major consequences of
photorespiration
8. Describe two important photosynthetic
adaptations that minimize photorespiration