318.T1

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Photosynthesis

Photo + Synthesis

• Photosynthesis is made up of two Latin words.

• Photo is the first; it means “light”.

• Synthesis is the second; it means “to put together”.

318.T2

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Photosynthesis

Requirements for Photosynthesis

• In order for photosynthesis to occur, three things must be present and available to the plant.– Water– Carbon Dioxide– Solar radiation (sunlight)

318.T3

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Photosynthesis

What Does Photosynthesis Do?

• Transforms sunlight into chemical energy (sugars).

• Fixes atmospheric carbon.

• Produces oxygen as a by-product.

• Frees water from the atmosphere.

318.T4

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Photosynthesis

The Equation for Photosynthesis

6 CO2 + 12 H2O -------> 1 C6 H12 O6 + 6 H2O+ 6O2

This means that carbon dioxide, water, and the sun’s energy are used by plants to make sugars, water, and oxygen.

Light Energy

318.T5

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Photosynthesis

Light Reactions

• This reaction only occurs during daytime, or when there is artificial light provided.

• Light energy is converted into chemical energy used during the later stages of photosynthesis.

318.T6

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Photosynthesis

Dark Reactions

• This reaction may occur at any time. It does not need light.

• Stored chemical energy made during the light reaction is used to change carbon dioxide to carbohydrates (sugars).