An Analysis Of The Photosynthesis Process From The Light Dependent And Light Independent Reactions
Introduction
This is the introduction to the topic. We will discuss the main points and ideas related to it.
As heterotrophs we are completely dependent on photosynthetic organs to provide us with the energy-producing organic plant matter. Photosynthesis has been around for a long time and is one of our most basic processes. It is because it is so important that we study photosynthesis. Scientists who can conceptualize what plants must do to produce our needs are theoretically better prepared to make more efficient laboratory plants. What are the needs of these plants? Two chemical reactions are involved in the photosynthetic processes. The Calvin Cycle and the Light Reaction. The first series of reactions requires light to continue and is often referred as the light-dependent reaction. In it, color pigments found on plant leaves capture electrons before passing them onto a coenzyme named NADP+. NADP+ is similar NAD+ as used in aerobic metabolism. The final process yields energy in the form of NADPH as well as ATP through the process of photophosphorylation. The second set, also known as light independent reactions (or the light-independent reactions), continues as long as ATP or NADPH is available. The reaction converts atmospheric CO2 into an organic molecule that can be stored, usually glucose due to its ease of conversion to more complex molecules. (BIO 1510 Laboratory Manual, 2015, 131) We tried to analyze the photosynthetic reaction from both light-dependent and light-independent reactions.
The first experiment examined the pigments that are involved in the photosynthesis process. We analyzed four organic pigments using Thin Layer Chromatography. Chlorophyll is the primary pigment needed for photosynthesis. They also contribute to the change in color of the leaves during autumn. The Chlorophyll A, which is blue-green, dies as the temperature drops. This leaves the Carotenoids (yellow-brown). Our TLC Strip was expected to look the same as the one on the Bio Lab Book’s back cover.
Experiment Two was designed to find out how much oxygen is released when the photosynthetic activity absorbs light of different wavelengths, and also the availability CO2. Based on information gathered during experiment 1, we knew that Chlorophyll A’s color was blue-green. This pigment accounts for 75% or more of all pigments in plants. The “BIO1510 Laboratory Manual,” published in 2015, page 133, made us believe that red light would be more effective than blue. The blue light will still be more powerful than the white light when compared because that’s all the blue tubes can handle. White light is a good standard because it’s a constant. This experiment can be used to test the availability of CO2. We did this by using a different amount, but the same procedure.
In experiment 3, we sought to compare the qualitative reactions of light and light. We hypothesized we could observe the reaction by observing the color changes. Only the tube exposed to light was expected to change colour. We expected only the tube that was left in the light to change color. The tubes were arranged so that one was dark, one had chloroplasts denatured, and the third did not contain DCPIP. It is necessary for the light to react to have chloroplasts in the tubes, light access, and the NADP+. In this case it was the artificial DCPIP. The BIO 1510 Laboratory Manual (2015, p. 131) was created in 2015.
These three experiments are described in the laboratory manual on pages 135 – 140. Note that for experiment 1, the TLC sheet is 15cm in length. In the second experiment, instead of every table or group doing every CO2 color combination possible, we all did just one tube. After an hour’s analysis, our results were compared.
Our chromatography sample is similar in appearance to that found on the back of a lab manual. But our xanthophyll comes much closer, it is actually the nearest. We did also not see any phaeophytins – degraded versions of chlorophyll – in our chromatography strip.
DiscussionThe experiments were successful at gaining an understanding of the fundamentals of the photosynthetic system. In experiment 1, we looked at the pigments responsible for photosynthesis, and in experiment 2, we examined which lighting conditions were most conducive to their effectiveness. Last but not least, experiment three attempted to give a qualitative glimpse into the photosynthesis light-dependent process.
We followed the procedure but made errors in collecting our data. There are four big errors that need to be noted. In experiment 2 with dataset White light and 0% NaHCO3, the blue light produced the expected results for efficient oxygen production. The tube that was used had a higher photosynthesis. We concluded that either this was a mistake in measuring or that deionized drinking water has more oxygen than tap water. The group using the green tube failed to take into account the weight of their initial biomass. We could not calculate the photosynthetic capacity of the tube. The third error is due to the procedure that told us to use more DCPIP. The 20 minute period of time wasn’t enough for chloroplasts, as no color change in any tubes was observed. This meant that our hypotheses weren’t able to be tested.
This lab work can help us answer a real-world question. It’s about an annoying weed that can ruin camping trips and make you itchy. In this case, we are referring to the worldwide population of poisonivy. This plant has a slightly unique photosynthetic method. Poison Ivy benefits from a higher CO2 environment. Global warming and the increased release of carbon dioxide will increase the overall population of poisonivy. On your next nature hike, look out for larger populations of poison-ivy.
