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

2. Objectives
Relate producers to photosynthesis.
Describe the process of photosynthesis.

3. Vocabulary
Photosynthesis
Process by which light energy is converted to chemical energy; produces sugar and oxygen from carbon dioxide and water.
Chlorophyll
Light-absorbing pigment molecule in photosynthetic organisms.
Thylakoid
Membrane-bound structure within chloroplasts that contains chlorophyll and other light-absorbing pigments used in the light-dependent reactions of photosynthesis.

4. Vocabulary
Light-Dependent Reactions
Part of photosynthesis that absorbs energy from sunlight and transfers energy to the light-independent reactions.
Light-Independent Reactions
Part of photosynthesis that uses energy absorbed during the light-dependent reactions to synthesize carbohydrates.

5. 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.

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

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

8. The light-dependent reactions capture energy from sunlight.
take place in thylakoids
water and sunlight are needed
chlorophyll absorbs energy
energy is transferred along thylakoid membrane then to light-independent reactions
oxygen is released

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

10. 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)

11. Question/Answer
Describe the importance of producers and photosynthesis.
Photosynthesis enables producers to capture energy from sunlight and make sugars that store chemical energy. The food produced becomes a source of energy for nonproducers.
Where do the light-dependent and light-independent reactions occur?
Thylakoid membranes, stroma
What are the reactants and the products in photosynthesis?
The reactants are carbon dioxide and water. The products are oxygen and sugar.