Lab de fotosintesis (ingles)

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Plant Pigments/Paper Chromatography
Due date: 21 October 2011
Ap biology

Introduction and Objective
The purpose of this lab experiment was to separate plant pigments using paper chromatography, and measure the rate of photosynthesis in isolated chloroplast. Because of capillary action solvent moves up the paper causing the pigments to become visible at certain distances.
To measurelight transmittance in chloroplast a spectrophometer 20 will be used. The reason behind measuring the light transmittance is to calculate the rate of photosynthesis in the chloroplast.
Materials
This lab requires spinach, coins, erlenmeyer flask, filter paper, pencil, petroleum spirit (90%) and acetone (10%)/ isopropyl alcohol (70%).
Data
Distance Moved by Pigment Band #1
Brand Number |Distance (mm) | Band Color |
1. Starting point-b | 10mm | White-Green |
2.b-a | 64 mm(54mm) | Light Green |
3.a-xantho | 74.5(10.5mm) | Green |
4.xantho-carotene | 82.5 (8mm) | Yellow |
5.carotene-Finishing point | 86 (3.5mm) | White |
Distance Solvent Front Moved: 86mm
Rf #1
Rf for carotene (yellow to yellow orange) | 1 |
Rf for Xanthophyll (yellow) | 0.95 |
Rf for Chlorophyll a(bright green to blue green) | 0.86 |
Rf for Chlorophyll b (yellow green to olive green) | 0.74 |

Distance Moved by Pigment Band #2
Brand Number | Distance (mm) | Band Color |
1. Starting point-b | 8mm | White-Green |
2.b-a | 49 mm(41mm) | Light Green |
3.a-xantho | 59.5 (10.5mm) | Green |
4.xantho-carotene | 76.5 (17mm) | Yellow-Green |
5.carotene-Finishing point | 77.5 (1mm) |Orange |
Distance Solvent Front Moved: 77.5mm
Rf #2
Rf for carotene (yellow to yellow orange) | 1 |
Rf for Xanthophyll (yellow) | 0.98 |
Rf for Chlorophyll a (bright green to blue green) | 0.76 |
Rf for Chlorophyll b (yellow green to olive green) | 0.63 |

Absorbance/wavelength data table
Wavelength | Chlorophyll a | Chlorophyll b | Xanthophylls | Carotene | Total Pigment |
400 | 0.700| 0.185 | 0.055 | 0.950 | 1.89 |
420 | 0.760 | 0.159 | 0.059 | 1.025 | 2.003 |
440 | 0.694 | 0.118 | 0.049 | 1.005 | 1.866 |
460 | 0.542 | 0.093 | 0.042 | 0.830 | 1.507 |
480 | 0.408 | 0.163 | 0.112 | 0.650 | 1.343 |
500 | 0.116 | 0.041 | 0.007 | 0.317 | 0.454 |
520 | 0.060 | 0.038 | 0.002 | 0.252 | 0.352 |
540 | 0.068 | 0.0501 | - 0.001 | 0.200 | 0.3171 |
560 | 0.080 | 0.089 | -0.007 | 0.085 | 0.247 |
580 | 0.113 | 0.130 | - 0.001 | 0.011 | 0.253 |
600 | 0.175 | 0.215 | - 0.002 | 0.003 | 0.391 |
620 | 0.290 | 0.364 | 0.001 | 0.012 | 0.668 |
640 | 0.268 | 0.314 | - 0.001 | 0.002 | 0.583 |
660 | 0.149 | 0.125 | - 0.004 | 0.005 | 0.275 |
680 | 0.062 | 0.041 | - 0.000 | 0.005 | 0.108 |
700 | - 0.002 | - 0.009 | - 0.031 | - 0.018 | -0.06 |
720 | 0.086 | 0.050| 0.006 | 0.084 | 0.226 |
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Questions
Assigned questions (1-9)
1. Which pigment migrated the farthest and why ?
a. Carotene, it was the most soluble and didn’t form bond with the filter paper.
2. Which of the two forms of chlorophyll is more soluble? Explain.
b. Chlorophyll a, and the reason is that the difference in their structures is that at one point in themolecule chlorophyll has a CH3 group and chlorophyll b has a O=C-H group. This small difference in charge is enough to affect their solubility and absorption spectrum.
3. Why do leaves in temperate zones change color in the autumn season?
c. The chlorophyll production in the leaves slows down. In Autumn, chlorophyll starts to break down which allows the other brilliant plant pigment colorsto show. These pigments include the red, orange, and yellow colors.
4. What is the function of the chlorophyll in photosynthesis?
d. They absorb red and blue light rays.  Plant pigments trap light energy and convert it into chemical energy that can be used by the plant to make glucose or sugar.
5. What are accessory pigments and what are their functions?
e. Carotene and...
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