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Lab 4 Energy and Photosynthesis BIO101L

Energy and Photosynthesis 

Pre-Lab Questions

  1. Describe how the functional units for beta carotene, xanthophyll, chlorophyll A, and chlorophyll B are different. Be sure to identify the subunits that adhere to paper during chromatography.
  2. Describe a technique for measuring photosynthetic rate.
  3. Many deciduous trees have leaves which turn yellow in the fall. What do you suppose is happening in the leaves at the cellular and molecular level?
  4. Chloroplasts and mitochondria are both are unusual in that they have double membranes and contain their own set of DNA. Can you think of any explanations for this observation?

Experiment 1: Paper Chromatography

Table 1: Part 1: Chromatography Data

Solvent Distance from Original Line to Solvent Font Number of Bands Rf Factor
Acetic Acid
Mineral Oil

Table 2: Part 3: DPIP Photosynthesis Data

Test Tube Chloroplast Solution Present? Initial Color Final Color Time Required to Change Color (Hours)

Post-Lab Questions

  1. What did the different colored bands signify in each solvent for Part 1? What pigments can you associate them with?
  2. What is the osmolarity fluid used in Part 2? Why is this important? Why is it essential to keep it cool?
  3. How could you modify this experiment to show the effects of different wavelengths of light on the photosynthetic rate?
  4. Some plants (grasses) tend to contain a greater concentration of chlorophyll than others (pines). Can you develop a hypothesis to explain this? Would it be testable?
  5. Insert a picture of the four pieces of chromatography paper with your name clearly and access code handwritten in the background. (Part 1)
  6. Insert a picture of the final color of the solutions in their test tubes with your name and access code handwritten in the background. (Part 3)

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