Photosynthesis Lab

HYPOTHESIS
LAB 7 Photosynthesis
In exercise 1, I hypothesize that the most soluble pigments in the solvent will move furthest on the chromatography paper.
In exercise 2, I hypothesize that the light-adapted algae sample will absorb more light than the dark-adapted sample.
INTRODUCTION
In exercise 1, the photosynthetic pigments in spinach leaf extract will be separated using chromatography paper. Chromatography is a technique used by scientist to separate substances from a mixture in order to determine what that mixture is made up of. A small sample of the mixture will be added to the chromatography paper and put in a solvent tank so the bottom of the paper makes contact with the solvent. The chromatography paper has capillaries so once the

The distance the substance has moved can be calculated by the retention factor, Rf, the distance the color has traveled divided by the total distance the solvent has traveled. The Rf value is also an indication of how soluble substances are in a given solvent. Rf values closer to 1 indicate that the substance is very soluble in the solvent and smaller Rf values indicate substances that are not as soluble in the solvent. In the spinach leaf extract, we will be looking for the separation of chlorophyll a, chlorophyll b, lutein and β-carotene. In exercise 2, chlorophyll a and chlorophyll b will be studied in Chlamydomonas reinhardtii algae. One sample will be from algae that are adapted to dark light and another that are adapted to dark light. Chlorophyll a and b are important pigments in plant cells because they allow photosynthesis to occur by absorbing light and converting it to light energy for the plants use. Chlorophyll b is considered an accessory pigment because it transfers the light it absorbs to chlorophyll a to be converted to light energy. (University of Miami) Chlorophyll a and b both absorb red and blue light and reflect