Testing Your Knowledge

1. What are the functions of the following molecules in the light reactions?

2. Define these terms and arrange them from smallest to largest:

3. List the reactants and products of the light reactions of photosynthesis.

4. Why are two photosystems better than one?

5. How does photorespiration counter photosynthesis?

6. How is CAM photosynthesis adaptive to survival in a particular environment?

7. How is C4 photosynthesis an adaptation based on a spatial arrangement of structures, whereas CAM photosynthesis is temporally based?

1. What was a possible source of carbon dioxide for the earliest photosynthesizing organisms?

2. Why are proteins necessary for photosystems to function?

3. Why are plants green?

4. Accessory pigments vary in color and chemical structure, yet they share a common function in photosynthesis. What is it?

5. How were isotopes used to reveal the intermediates of the Calvin cycle?

6. The carbon reactions were once called the dark reactions. Why is the older term not quite accurate?