Lab 4 Photosynthesis Pre Lab

Pre-lab for Photosynthesis 1.



Name

Describe how the method of paper chromatography can be used to separate molecules such as pigments from cell extracts.

2. What two factors cause pigments to move at different rates? Explain in terms of hydrogen bonding.

3. Explain how the chemical makeup of the four pigments allows us to predict the way they sort out on the chromatogram.

4. In addition to capturing additional wavelengths of light and passing them on to the main photosynthetic pigment (chl a), what role do carotenoids play in photosynthesis?

5. Write the formula for R f value and sketch a chromatogram with the distances labeled.

6. Describe the relationship among wavelength, frequency, & energy of EMR, and account for the fact that only visible light is successful in driving photosynthesis.

7. Summarize what happens in photosynthesis. (hint: see lab, paragraph 2, middle of p. 48)

8. This experiment tests the hypothesis that two things are required for the light reactions to occur. Identify the two things.

9. What chemical will be substituted for NA DP+ as an electron acceptor, and how will we know that it has accepted boosted electrons [has been reduced]? Where c/o the e- come from?

10. How will the gradual decolorization of the dye be detected & measured in our design?

11. What is the source of chloroplasts for this experiment? 12. Study table 4.3 that outlines the setup for the time course of reaction study. There are several controls---identify the specific purpose of each of the following: tube 2 (dark) tube 4 (boiled chloroplasts) tube 5 (no c !crop! as ts) 13. What is the purpose of tube 1 (blank)?

14. Which tube represents the actual experiment where the light reactions will occur?

15. What is added to initiate the reaction that you will monitor over the 15 minutes?

16. Describe how the tubes will be incubated during the experiment. What precaution is taken?

17. Predict how % transmittance is expected to change in: tube 2 tube 3 tube 4 tube 5