For this lab the focus is Photosynthesis, and in particular we will be focusing on the pigments that trap solar energy thereby providing the energy required for this anabolic process. Anabolic means that we are dealing with chemical reactions that 1) build complex products from simpler reactants, 2) require energy and 3) the products produced store energy within their chemical bonds. The general process -the chemical formula- for photosynthesis is shown below.
Two simple reactants (carbon dioxide and water) are used to build a complex product (glucose). The other simpler product of the reaction, the oxygen gas, is simply a byproduct of the anabolic production of glucose. Sunlight, specifically the high energy photons of sunlight (solar energy), provide the Energy to build the chemical bonds of glucose. Specifically, the photon energy is converted to electron energy and cellular energy (ATP).
Photosynthesis is simple in concept. In a nut shell, the water is split (solar energy used to split water into hydrogen(H2) and oxygen(O), and then the freed hydrogen atoms (H2) are used to reduce the carbon dioxide. Imagine inserting the “H2” into the CO2 to form a carbohydrate unit…..CH2O…. Put 6 of these -CH2O-together with chemical bonds and you have a glucose molecule. Water is split and carbon dioxide is reduced. Voila! We have produced glucose, a 6 carbon sugar!
In concept simple and elegant. However, it takes a lot of chemical steps. These are all divided into two sets of reactions: the light reactions and the Calvin Cycle. We are NOT going to go through these reactions-you will cover these in another course . Here today we are ONLY going to be looking at the pigments that capture the solar energy, the energy that is required to fuel the process. Remember–there is no formal discussion for this lab. Just make sure that you answer all of the questions (except those I deleted) completely AND do not forget to include your calculated Rf values when appropriate in your answers!! Always try to discuss your results both qualitatively and quantitively!! Do not forget the heeding of Lord Kelvin…
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