PHOTOSYNTHESIS (2015) Presented by Amanda Moore & Kathryn Shaull

Photosynthesis Photo = “Light” Synthesis = “Putting together”

Definition Photosynthesis is the process of plants using energy of light to put together useful chemicals.

Importance of Photosynthesis Source for carbon based fuels –Oil –Coal –Wood –Natural Gas Source for all food –All animals are dependent on plants

Three Important Processes Transforms light energy from the sun into chemical energy Fixes carbon dioxide into sugar (future energy source) Produces oxygen as a by-product

Energy Transformation Earth receives energy from sun Plants capture this energy through photosynthesis -Radiation energy (sun)  Chemical energy (useful energy) Example: Sugar

Carbon Fixation Photosynthesis takes CO2 and converts it (through plants) into carbohydrates. –Plants convert ~620 bil tons per year

Oxygen Production Plants are the primary source of oxygen world wide –Oxygen is a by product of plants! Key sources are: –Rain Forests –Phytoplankton in the Oceans

Plants are Unique Plants  autotrophs –They are Self sufficient Animals and Fungi  heterotrophs -Need plants to survive

Plants are Unique Plants do depend on and interact with other living creatures

Process of Photosynthesis Requirements Products Reactions

Requirements for Photosynthesis Chloroplasts Lots of CO 2 Water (H 2 O) Light Suitable Temperature

Products of Photosynthesis Carbohydrates (photosynthates) –Examples: sugars and starches Water (H 2 O) Oxygen (O 2 )

The Reaction (6) CO 2 + (12) H 2 O Green Plant & Light Energy (1) C 6 H 12 O 6 + (6) H 2 O + (6) O 2

Light Reactions Occurs only during the day time Driven by sunlight Definition –Light received by the plant is transferred to energy holding chemicals used in later stages of Photosynthesis

Dark Reaction Takes place at anytime Is not dependent on light Definition –the energy-holding chemicals created in the light reaction are used to change carbon dioxide to carbohydrates (sugar) and water.

Photosynthetic Chemical Activity Takes place within plant organelles called Chloroplasts Chloroplasts are found in: –mesophyll cells of leaves –green stems –unripe fruits

Photosynthetic Chemical Activity Photosynthesis is dependent on the presence of the chemical chlorophyll –Chlorophyll makes the plants green. –Captures light energy