Introduction to
Photosynthesis
The Word
• Sometimes you can learn a lot about
something by looking closely at the word
that describes it.
• The word photosynthesis is made up of a
prefix (photo) and a root word
(synthesis).
Photo + Synthesis = Photosynthesis
so what does it mean?
Photosynthesis
A definition:
• "The process in green plants and certain
other organisms by which carbohydrates
are synthesized from carbon dioxide and
water using light as an energy source”
Four things are needed for photosynthesis:
SUNLIGHT
Gives the plant energy
WATER
Travels up
from the roots
CARBON DIOXIDE
Enters the leaf through small
holes on the underneath
CHLOROPHYLL
The green
pigment
where the
chemical
reactions
happen
The word and chemical equations for photosynthesis:
Carbon dioxide + water
Sunlight
Chlorophyll
glucose + oxygen
Sunlight
6CO2
+ 6H20
Chlorophyll
C6H12O6 + 6O2
Plant SUMMARY
Plants make their own food, glucose, by
photosynthesis.
It only happens during the daytime when there is
light available.
carbon dioxide + water
Raw materials

glucose + oxygen
chlorophyll Products
This happens in plant cells containing the chemical
chlorophyll (green-coloured) which traps the light
energy.
The plants have captured light energy and turned
it into a store of chemical energy (glucose).
More on the uses for glucose shortly…