AP LAB #4

AP LAB #4

Exercise 4A
1. Factors such as the time and distance are involved with the separation of the pigments in the chromatography experiment. Additionally, the solubility in the solvent and the absorptive surface should also be factored in.

2. No, I would not expect the Rf values to be the same in different solvents because the Rf value is calculated by the distance the pigment migrates over the distance the solvent migrates. Both values depend on the solvent chosen. The distance the solvent moves in that time depends on the solvent. The distance the pigment moves also depends on the solvent.

3. The reaction center in the chloroplast contains chlorophyll a. The other pigments are used to capture light and energy from, which is transferred to the reaction center. Of these pigments is additional chlorophyll and carotenoids.

4. Our hands touching the paper or creases on the paper would have resulted in altered date. Other discrepancies can be due to the fact that we had to eyeball the separation of the pigments which could cause slight errors.

5. Another possible experiment would be to switch the solvents used for the spinach and marker.

Exercise 4B
1.   The DPIP is used as a substitute for the NADP as an acceptor for electrons removed from the Water. It is the electron carrier.

2. The DPIP replaces the NADP.

3. Electrons used for the reduction of DPIP are from broken down water molecules transferred to the chloroplast.

4. The spectrophotometer measured the amount of light transmittance through the solution in the cuvettes.

5. See Graph.

6.   DPIP isn’t reduced in the dark because light is necessary for the electrons being boosted. If there is no light, the electrons wouldn’t be boosted, and the DPIP won’t be reduced.

7.   In boiling the chloroplasts, the protein molecules will be denatured, halting the reduction of DPIP.

8. The chloroplasts kept in light are able to take the electrons from the water and transfer them to the...