PRIZE-WINNING PHOTOSYNTHESIS RESEARCH

Photosynthesis is a two-part pathway. In the first steps, energy from the sun is converted to chemical bond energy of ATP. In the second steps, ATP gives up energy at sites where glucose and other organic compounds are synthesized. How do we know such things? Our understanding of photosynthesis is based on observational and experimental tests that began in the mid-seventeenth century when T. Englemann used aerobic bacteria and the green algae Spirogyra to determine what light conditions were most favorable for photosynthesis. Fast forward to the twentieth century, and we find scientist Melvin Calvin using radioisotopes to learn the mechanism by which plants take up carbon and use it to make sugars--work for which he received the Nobel Prize in 1961.

ACTIVITY

In this activity, you will visit the Electronic Nobel Museum and the Botany Online site to learn about the photosynthesis research for which the 1961 prize was awarded. Information from Botany Online will round out your view of this research.

Part 1.

Go to the Nobel e-museum at http://www.nobel.se/index.html

Click the site's search button and use the "Find a Laureate" button to locate information about Melvin Calvin.

Additional information about Calvin's research and the reactions involved is available at http://www.biologie.uni-hamburg.de/b-online/e24/24a.htm (To view the molecular models you will need to use Netscape Navigator with the Chime plug-in. However, this is not necessary to complete this exercise.)

Use this information from these two sites to answer the following questions:

  1. What experimental organism did Calvin use to carry out most of his experiments?
  2. Describe how Calvin determined the sequence in which the products of the dark reactions were formed.
  3. Describe the structure of the first stable product formed.

Part 2.

Use your browser to go to http://www.biology.arizona.edu/biochemistry/problem_sets/photosynthesis_2/photosynthesis_2.html..

Go through the tutorial, answering the first five questions. Use what you have learned to answer the following questions:

  1. What enzyme catalyzes the reaction in which carbon dioxide was incorporated into 3-phosphoglycerate?
  2. What will happen to the levels of 3-phosphoglycerate and RuBP if the source of carbon dioxide is suddenly eliminated? Explain why.
  3. Where in the chloroplast is RuBP regenerated?