Analysis of the Absorption of Green Light Versus Red Light Absorption in Spinach Leaves

Have you ever really wondered how different variables can affect how plants go through photosynthesis? Well, in this experiment, the purpose was to see how various environmental conditions can affect the overall photosynthetic capacity of a specific plant. The factors, light, darkness, cold, and heat were applied to see how the different components would affect the photosynthesis on spinach plants. Each group was given a different factor to test. Out group was given the light factor. The hypothesis for this experiment is that when adding light as a factor, the light will affect the overall plant photosynthesis.

There are two main types of chlorophyll, chlorophyll a which absorbs wavelengths of 430nm (blue) and 662 (red) and is the main photosynthetic pigment, and chlorophyll b, which doesn’t directly participate in the photosynthetic process, but is capable of donating its energy to chlorophyll a

After the serial dilutions of the red and blue dyes were taken, the molarity and absorbance for both dyes were calculated. Using the MiVi = MfVf equation, the concentrations for each value of the red and blue dye were separately calculated. Calculating absorbances calls for setting the correct wavelengths of light for each dye. In this case, the 470 nm wavelength for red dye and the 635 nm wavelength for blue dye was needed to find the maximum absorbances. The absorbance was found by blanking the colorimeter and entering the concentrations. After both values of the absorbances and concentrations were found, the values were then graphed in order to obtain the equation of the relationship between absorbance and concentration.

Spectroscopy is the study of light. A spectrophotometer is a machine used to determine the absorbance of light at any given wavelength. It does this by using a source of white light through a prism, which gives multiple wavelengths that can be individually focused (Ayyagari and Nigam, 2007). Substances are put into cuvettes that are glass or quartz containers that light can easily travel through. The light that is being focused travels through the substance gets absorbed by the

The procedures for experiment A, B, and C all start the same. The first step is to put on goggles and get the data collection device set properly. The labquest needs to be plugged into the colorimeter accurately so that a click is heard when putting it in. The labquest needs to be reading digitally and the colorimeter needs to be set to 635 nm. Then shake the chloroplast solution and take a clean cuvette and fill it with 3 mL of distilled water, 3 drops of the chloroplast solution, and cap it. This is used as a blank to calibrate your labquest. Double check that the labquest is reading absorbance, this assures that the colorimeter is plugged into the labquest accurately. Insert the blank into the colorimeter and hit the calibration button. Take out the blank and empty it. The labquest is now set to experiment with. Make sure that the heat bank is set in front of the lamp and that the lamp is on. The cuvette must be placed on the opposite side of the heat bank in the path of light in the box so that no other light can interfere with the experiment.

Introduction: Photosynthesis can be defined as a solar powered process that removes atmospheric carbon dioxide and transforms it into oxygen and carbohydrates (Harris-Haller 2014). Photosynthesis can be considered to be the most important biochemical process on Earth because it helps plants to grow its roots, leaves, and fruits, and plants serve as autotrophs which are crucial to the food chain on earth. Several factors determine the process of photosynthesis. Light is one these factors and is the main subject of this experiment. The intensity of light is a property of light that is important for photosynthesis to occur. Brighter light causes more light to touch the surface of the plant which increases the rate of photosynthesis (Speer 1997). This is why there is a tendency of higher rates of photosynthesis in climates with a lot of sunlight than areas that primarily do not get as much sunlight. Light wavelength is also a property of

Scientists use an instrument called a spectrometer to quantitatively determine the amount of light absorbed by a solution. The primary inner parts of a typical spectrometer are described below. The spectrometer has a light source that emits white light containing a vast mixture of different wavelengths of electromagnetic radiation. The wavelength of interest is then selected using a monochromator (“mono” meaning one and “chromate” meaning color) and an additional exit slit. The separation of white light into different colors (wavelengths) is known as diffraction. The selected light then reaches the sample and depending on how the light interacts with the chemical compound of interest, some of the light is absorbed and some passes straight through. By comparing the amount of light entering the sample (P0) with the amount of light reaching the detector (P), the spectrometer is able to tell how much light is absorbed by the sample.

6. A spectrophotometer would definitely be useful in experiments involving the measurement of concentration that produces color, since the color absorbance can be used to find concentration. One experiment involving a spectrophotometer could be finding the molarity of a blue Copper(II) sulfate solution. The wavelength could be set to red, and then the absorbance values can be correlated to the molarity of Copper(II)

In the beginning of this experiment, our TA added water, salt, and 75/25 hexane/acetone to spinach leaves to a blender and blended the mixture to assume equal amounts for each group and to avoid erros if each student had to do the blending. The addition of the water to the mixture allowed the it to separate into a distinct organic layer after being run in a centrifuge, which was available to be collected at the top of the centrifuge. Salt reduces solubility, which will force the organic parts of the mixture (the desired pigments for example) to separate into the organic layer at the top. Lastly, 75/25 hexane/acetone is added because this is a moderately polar solvent and will useful for both the non-polar and polar pigments present within the spinach leaves. A mixed solution of hexanes and acetone must be used because acetone is very polar, while hexane in very non-polar, and the spinach leaves contain both non-polar and polar pigments in them that are important in the extraction and for further analysis. The mixture was placed in the centrifuge so the solids in the mixture (mostly cellulose) could be separated from the liquids into separate distinct layers for further extraction and testing. In the tube, the organic substances separated into the top layer, whereas the water layer remains at the bottom of the tube below the solid layer made up of mainly cellulose.

The initial experiment was a success. As our treatment group spent more and more time under the lights, the absorbance rate continues to decrease toward zero. Once our 30 minutes were up, the absorbance rate in each tube was significantly lower than at the start of our experiment. In contrast the two control groups did significantly lower the absorbance. Each control lacked one of the vital aspects of photosynthesis, one being light, and the other being chloroplast. Neither of the control groups (Control 1 or 2) showed any signs of photosynthesis. Control 1 was exposed to light, but contained no photosynthetic organelles thus the absorbance throughout the 30 minutes varied minimally, mostly staying stagnant. Control two which contained chloroplast but was not exposed to any light failed to lower the absorbance at all and in fact increased the absorbance over the 30 minutes. However, the treatment group contained both and ultimately performed photosynthesis as we expect therefore, confirming our assumption that chloroplast were the organelles required for photosynthesis in plants and that light is required to perform said photosynthesis. The treatment group, containing both the chloroplast and being exposed to light provided evidence that photosynthesis was taking place as the absorbance lowered at each 10-minute interval. Having a less absorbance would be desired because as DCIP became reduced we would expect the solution to become more and more clear, thus less

Pigments extracted from different greens have different polarities and may be different colors. Mixed pigments can be separated using chromatography paper. Chromatography paper is able to separate mixed pigments due to their polarity and solubility. Pigments of chlorophyll a, chlorophyll b and beta carotene will be separated on chromatography paper because each has its own polarity and solubility, which results in different distance traveled up the paper. Beta carotene is non-polar so it travels the highest distance, followed by chlorophyll a. Chlorophyll b is the most polar; therefore, it travels the shortest distance. The separated pigments on the chromatography paper can be eluted in acetone and absorbance spectrum is

The purpose of this experiment was to take spinach leaves and extract the chlorophyll and carotenoid pigments by using acetone as the solvent. The chlorophyll and carotenoid pigments were extracted by using column chromography and alumina was used as the solvent. Solvents of different polarities were used, starting with the least polar, to extract the certain components from the leaves. They were then analyzed by using thin- layer chromatography.

For lab 12, it is hypothesized that chlorophylls a and b are present in a plant leaf and contribute to the starch production in photosynthesis. Also, products of photosynthesis will be present in leaf tissue exposed to red and blue light wavelengths for several days, but a decreased presence in leaf tissue exposed to green and black light wavelengths. In lab 13, it is expected that since chlorophylls a and b are more polar and smaller molecules than the anthyocyanins and carotenoids, they will travel higher up the chromatography paper than the other pigments.

8) Steps 1 - 8 were repeated using the wavelengths of 360 nm to 900

Because chlorophyll-a takes in violet-blue, and orange-red lights to use in photosynthesis, it reflects green, and that is the color we see. This study investigates the relationship between the wavelength of light and the total respiration of the plant Elodea. The purpose is to see the effect of the presence or absence of certain wavelengths can have on the process of photosynthesis. Because Elodea is a plant that reflects green light, it can be assumed that red lights, the complimentary color to green will be absorbed the most contributing to the process of photosynthesis and respiration making the most oxygen.