Green plants, blue-green algae, and certain bacteria all carry out a process known as photosynthesis. The effect of this very complex series of chemical reactions is that organisms are able to use the energy of sunlight to produce oxygen and sugar. The process of photosynthesis is an example of a series of biological oxidation-reduction reactions.

In this Internet activity, you will examine some of the chemistry of photosynthesis and identify simplified forms of the half-reactions involved in the redox process.

Go to Photosynthesis on the University of Hawaii's Internet Chemistry Page and read the article, paying particular attention to the chemical equations. Then answer the following questions.

1. What is the overall chemical equation for the process of photosynthesis?
   
   
2. What is the chemical equation for the "light reaction"?
   
   
3. What is the chemical equation for the "dark reaction"?
   
   
4. Are the "light reaction" and "dark reaction" examples of redox half- reactions? How do you know?
   
   
5. Classify the "light reaction" as an oxidation or reduction reaction.
   
   
6. Classify the "dark reaction" as an oxidation or reduction reaction.
   
   
7. Show that the "light reaction" and "dark reaction" add to yield the overall reaction.
   
   

Additional Activities

1. The Online Biology Book has a well-illustrated introduction to photosynthesis.
   
   
2. The Web has many good sites on photosynthesis. One is What is Photosynthesis? Its links to articles about photosynthesis are rated by complexity.