1. KEY CONCEPT The overall process of photosynthesis produces sugars that store chemical energy.

2. Photosynthetic organisms are producers.
Producers make their own source of chemical energy.
Plants use photosynthesis and are producers.
Photosynthesis captures energy from sunlight to make sugars.

3. Chlorophyll is a molecule that absorbs light energy.
chloroplast
leaf cell
leaf
In plants, chlorophyll is found in organelles called chloroplasts (1).

4. Photosynthesis in plants occurs in chloroplasts.
Photosynthesis takes place in two parts of chloroplasts.
grana (thylakoids) (4)
Stroma (10)
chloroplast
stroma
grana (thylakoids)

5. The light-dependent reactions capture energy from sunlight.
take place in thylakoids
Water (3) and sunlight (2) are needed
chlorophyll (4) absorbs energy
energy is transferred along thylakoid membrane then to light-independent reactions (6)
oxygen is released (5)

6. The light-independent reactions (8) make sugars.
take place in stroma
needs carbon dioxide (7) from atmosphere
use energy to build a sugar (9) in a cycle of chemical reactions

7. The equation for the overall process is:
6CO2 + 6H2O  C6H12O6 + 6O2
C6H12O6
granum (stack of thylakoids)
thylakoid
sunlight
1 six-carbon sugar
6H2O
6CO2
6O2
chloroplast 1 2 4 3
energy
stroma (fluid outside the thylakoids)

8. What pigments are in leaves of plants?
Chlorophylls a and b
Carotene
Xanthophylls
Anthocyanin

9. What wavelengths of light do these pigments absorb?
What color of light is reflected? What colors of light are absorbed?

10. Why do some trees drop their leaves in the fall? (They are deciduous)
Change in angle of sunlight (shorter days/longer nights)
Colder nights

11. Evolution and changing leaf colors