Name ___________________________________________________ Date ___________ Period _______
TEXTBOOK READING PP. 327-336
Notes Photosynthesis
The complete, balanced equation for photosynthesis is . . .
Carbon Dioxide
Water
Light
energy
Chemical
energy
Sugar (Glucose)
Oxygen
Energy
Plants get their energy from the Sun.
Energy can be transferred from one
form to another.
During photosynthesis, light energy is
converted into chemical energy.
Light energy
The two main colors that plants
use for photosynthesis are the
blue and red wavelengths
Chloroplast
The organelle in the plant cell where photosynthesis occurs.
They contain a green pigment, chlorophyll, that absorbs
light. Plants appear green because green light is reflected.
Two Phases of Photosynthesis
Light-Dependent Reactions & Dark-Independent Reactions
Light-Dependent Reactions – the first phase of photosynthesis
1st – light energy hits a chlorophyll molecule in a chloroplast.
2nd – electrons in chlorophyll become excited
3rd – the light energy is converted into chemical energy, ATP
4th – the water, which is absorbed through the roots, is split into
oxygen and hydrogen. The by-product of this reaction is oxygen.
Dark-Independent Reactions – the second phase of photosynthesis
The light-independent reactions are referred to as the Calvin Cycle.
In a series of reactions, ATP and hydrogen produced during the lightdependent reaction are added to carbon dioxide to make sugars.
The sugar produced can be consumed by the plant as energy, stored by
the plant as starch, or used to form lipids, proteins and other molecules.
Although the light-independent reactions do not require light they occur
at the same time as the light-dependent reactions.