Chloroplast Membranes Lab Report

Aisha Shabbir
Basic Physiology and Biochemistry of Chloroplast Membranes
ABSTRACT
The purpose of this experiment was to understand the biochemistry and physiology of chloroplast membranes. The chloroplast pigment extract and the chloroplast membrane suspension have different physiological abilities and functions. Chloroplast pigment extract is useful in establishing an absorption spectrum, fluorescence of isolated chlorophyll and membrane pigment separation through paper chromatography. Chloroplast membrane suspension is useful in analyzing membrane physiology as well as generating energy and electrons. We focused on the high energy electrons that were formed to see what colors of visible light affected the energy levels the most in the membrane. For experiment two, we discovered the peak absorbance regions by measuring the wavelength of the pigment extract and 4 ml of 80% acetone starting at 340 nm until we reached 740 nm using a spectrophotometer. For experiment three, we used many different conditions to see what affected the wavelengths of the spectrophotometer at 605 nm. We created six trials during the Hill reaction to see the dye reduction with the different combinations of CMS, DCIP, and colored light. The peak absorbance regions were blue/violet light at 440 nm and red light at

Wavelength
A graph was plotted on MS Excel with absorbance on the y-axis and wavelength (nm) on the x-axis. The absorption rate initially increased until the peak of 440 nm was reached (see Figure 1). After the decline of the first peak, the rate increased until the next peak was reached at 670 nm. The peak absorbance region was at 440 nm with an absorption rate of about .818 and at 670 nm with an absorption rate of about .431. Thus, the highest absorbance values were reached at the wavelengths 440 nm and 670 nm.

Figure 1 Effect of different wavelengths on the absorption rate of isolated chloroplast pigments

• Experiment 3: Hill