Photosynthesis
• Photosynthesis is the process by
which plants make their own food.
Why Study Photosynthesis?
• Photo means light
• Synthesis means put together.
• Photosynthesis is how plants
make their own food
We all need photosynthesis!
• Directly or indirectly, all life on Earth
depends on photosynthesis.
– Plants take in carbon dioxide &release oxygen
which controls our atmosphere
– Animals and humans need oxygen to breathe
– Plants create their own food (sugar) to grow.
– Animals and humans eat the plants for food and
energy
– Plants provides energy - the energy stored in
petroleum, natural gas, coal, and firewood all
came from plants which have stored the energy
from the sun via photosynthesis
Photosynthesis
• How green plants make their
own food
• Plants Need
– Light - from the sun
– Water - from roots
– Carbon dioxide – from air,
enters plant through tiny
openings under the leaves
called stomata
– Chlorophyll: green color in
plants that traps energy from
sunlight to make food
Photosynthesis
• A chemical reaction makes
glucose (sugar) and
oxygen from the carbon
dioxide and water
• The plant keeps the
glucose (sugar) as the main
source of nutrition or food for
the plant; helps plant grow.
• The plant releases the
oxygen into the atmosphere.