KEY CONCEPT
The overall process of photosynthesis produces sugars that
store chemical energy.
Photosynthetic Organisms are
Producers
• Producers are
organisms that make
their own source of
chemical energy.
– Plants use
photosynthesis and are
producers.
Photosynthesis in plants occurs in chloroplasts
• In plants, chlorophyll is found in organelles called chloroplasts.
– Chlorophyll is a molecule that absorbs light energy.
leaf
• Photosynthesis takes place in two parts of chloroplasts:
1. Granum (Looks like roll of Quarters)
a. Are stacks of thylakoids (Each quarter within the roll)
2. Stroma (Kind of like the cell’s cytoplasm)
leaf cell
chloroplast
There are two types of reactions that
take place in Photosynthesis:
First: Light-dependent reactions.
Second: Light-independent reactions.
First
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 the
light-independent reactions.
– Oxygen is released.
Second
The light-independent reactions make sugars.
– Takes place in stroma.
– Needs carbon dioxide from atmosphere.
– Use energy to build a sugar in a cycle of chemical reactions
The equation for the overall process of
photosynthesis:
6CO2 + 6H2O  C6H12O6 + 6O2
Granum (stack of thylakoids)
1
6H2O
6O2
2
Thylakoid
energy
Stroma (fluid outside the thylakoids)
6CO2
3
4
Chloroplast
C6H12O6 = 1 six-carbon sugar
Questions
Directions: Answer or complete the following on your
notes using complete sentences. I will be checking your
notes and answers tomorrow.
1. Draw the picture of the chlorplast on the last page
of notes being sure to label the products and
reactants, sunlight, granum, thylakoid, & stroma.
2. Write a paragraph summarizing the steps of
photosynthesis using the words: thylakoid, lightdependent reactions, stroma, and lightindependent reactions.