The purpose of this lab is to determine which pigments in a plant support or effect photosynthesis, based on starch production, which wavelengths of light are involved in photosynthesis, and identify plant pigments found in a plant leaf by means of paper chromatography. Life on Earth is dependent entirely on the energy from the Sun, not only to keep the planet at a suitable temperature but also to provide the energy required to sustain life. The energy of the Sun, in the form of photons, is actively captured by chlorophyll and related pigments present in photosynthetic organisms, like plants and algae. This captured energy is used to convert carbon dioxide into complex energy-rich molecules that can be used by themselves or other organisms. “Photosynthesis is the conversion of light energy to chemical energy in the form of sugar and other organic molecules.” (Russell, Wolfe, Hertz, & Starr, 2010). Photosynthesis can be categorized into two main processes: light-dependant reactions and light-independent reactions. For the purpose of this lab, light-dependant reactions will be investigated. The reactants involved in photosynthesis include carbon dioxide, water and sunlight to produce glucose, oxygen, and water. The light reactions involve the capture and use of light energy by pigment molecules to synthesize NADPH and ATP. Plants use this light energy to produce glucose from carbon dioxide. The glucose is stored mainly in the form of starch granules, in the chloroplasts of cells. Glucose in the form of starch is non-polar and is not soluble in water, allowing it to be stored much more compactly. The chloroplast is formed from an outer membrane, an inner membrane, and an intermembrane compartment. The aqueous environment within the inner membrane is called the stroma. Within the stroma is the thylakoids, which are flattened, closed sacs. It is in these sacs that the specific molecules required to carry out the light reactions of photosynthesis are
References: Benya, M. (2009, June 12). Biology. Retrieved December 10, 2010, from Milan High School: http://www.milan.k12.mi.us/~wbenya/Biology/ Fehrman, K. R., & Fehrman, C. (2004). Colour: the secret influence. Upper Saddle River, NJ: Pearson Education. Oracle ThinkQuest. (2010, August 25). Photosystems. Retrieved December 10, 2010, from Cellupedia: http://library.thinkquest.org/C004535/photosystems.html Russell, P. J., Wolfe, S. L., Hertz, P. E., & Starr, C. (2010). Biology: Exploring the Diversity of Life. USA: Nelson Education Ltd. Lederer, Alison (2008) "Investigation of Photosynthetic Properties in Spinach and Geranium: Pigments, Starch Production, and Light Wavelength Absorbance," ESSAI: Vol. 5, Article 29. Available at: http://dc.cod.edu/essai/vol5/iss1/29