1. KEY CONCEPT The overall process of photosynthesis produces sugars that store chemical energy.
These diatoms are single-celled algae that use the process of photosynthesis to store chemical energy. Animals eat photosynthetic organisms such as plants and algae to get this chemical energy. Photosynthetic organisms also produce the oxygen that is required to release much of the chemical energy in sugars.

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.
Apply: Describe the importance of producers and photosynthesis.

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

4. Photosynthesis in plants occurs in chloroplasts.
Photosynthesis takes place in two parts of chloroplasts.
grana (thylakoids) - Grana are the stacks of coin-shaped, membrane bound compartments called thylakoids.
Stroma – is the fluid that surrounds the grans in side a chloroplast.
chloroplast
stroma
grana (thylakoids)

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

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

7. The equation for the overall process is:
6CO2 + 6H2O + sunlight 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)
Summarize: How is energy from sunlight used to make sugar molecules?