Plant Pigments and Photosynthesis Lab Report
...P and NADPH work to fix the carbon in Carbon Fixation. This is called the Calvin Cycle. Through the Calvin cycle glucose is produced. So basically, Photosynthesis takes place in two main parts. In the first part, energy is captured, in the second part the energy is used to make sugar. In this lab we were looking for whether or not light and chloroplasts are required for light reactions to occur. The hypothesis would be: If light reactions occur, then light and chloroplasts must be present. The purpose of this lab is to learn how to separate pigments, and calculate their Rf values, to learn of a technique to describe photosynthetic rates. Also to compare photosynthetic rates at different light intensities or different wavelengths of light using controlled experiments. The last purpose is to learn why the rate of photosynthesis varies under different environmental conditions. The procedures that we used are as follows. First, we took a 50 ml graduated cylinder that had 1cm of solvent on the bottom. We cut a piece of filter paper to reach the solvent, we cut one end of it. We then drew a line 1.5 cm above the point. We used a coin to take out the pigments from spinach leaf cells. After that we placed a small section of leaf on the top of the pencil line. We then put the chromatography paper in the cylinder in the solvent, making sure the pigment didn’t touch the solvent. Then, we put a stopper in the cylinder. When the solvent was 1 cm from the top of the paper, we removed the paper and marked the location of the solvent. Our group then marked the bottom of each pigment band. After measuring the distance each pigment moved from the bottom of the origin to the bottom of the separated pigment band, we recorded the distances in Table 4.1. Table 4.1 Band Number Distance (mm) Band Color 1 35 Dark Yellow 2 26 Yellow 3 10 Light Green 4 5 Green On Thursday we did the second part of the lab. First, we warmed up the spectrophotometer and set the wavelength to 605 nm. We took cuvettes and labeled them 1 through 5. The control cuvette was #2, we had to put foil around it and cover the top so that light could not get through. We added 1ml of phosphate buffer in each cuvette. We added 4 ml of distilled water to cuvette #1. To #2, 3, and 4 we added 3ml of distilled water and 1 ml of DPIP. To cuvette #5 we added 3ml plus 3 drops of water and 1ml of DPIP. This is how the cuvettes were set up: Cuvette #’s 1 2 3 4 5 Phosphate buffer 1mL 1mL 1mL 1mL 1mL Distilled Water 4mL 3mL 3mL 3mL 3mL+3drops DPIP ~ 1mL 1mL 1mL 1mL Un-boiled Chloroplasts 3 drops 3 drops 3 drops ~ ~ Boiled Chloroplasts ~ ~ ~ 3drops ~ We then brought the spectrophotometer to zero, and added 3 drops of un-boiled chloroplasts to cuvette 1. We covered the top and mixed cuvette 1. We then put it into the sample holder and put the spectrophotometer to 100% transmittance. We then put 3 drops of the un-boiled chloroplast solution and put it into cuvette 2, then mixed it. We removed it from the foil and put it into the spectrophotometer. We put it on the...