A Spectrophotometric Analysis of the Absorption of Green Light Versus Red Light Absorption in Spinach Leaves The goal of the experiment was to determine if green light had less ability to absorb than red light in spinach leaves. This was done by separating the photosynthetic pigments (chlorophyll a, chlorophyll b, carotene and xanthophylls) from one another using paper chromatography. The separated pigments were then analyzed for their absorption spectrum using a. When the data was graphed it clearly showed the higher rate of red light absorption over green light. These results along with previous research indicate the importance of red light in photosynthesis and the minor role green light plays. The majority of life on Earth depends on photosynthesis for food and oxygen.
Photosynthesis is the conversion of carbon dioxide and water into carbohydrates and oxygen using the sun’s light energy (Campbell, 1996).
This process consists of two parts the light reactions and the Calvin cycle (Campbell, 1996).
During the light reactions is when the sun’s energy is converted into ATP and NADPH, which is chemical energy (Campbell, 1996).
This process occurs in the chloroplasts of plants cell. Within the chloroplasts are multiple photosynthetic pigments that absorb light from the sun (Campbell, 1996).
The Term Paper on Light Quality On The Rate Of Photosynthesis Measure
Abstract This study was undertaken to determine the relationship of different wavelengths of light and the rate of photosynthesis in spinach leafs. The rate of photosynthesis was measured every five min under light colors of white, green, red, blue and yellow under a light intensity of 2000 lux. The rate of photosynthesis was measured by the spinach disk method in which we replaced the air from ...
Photosynthetic pigments work by absorbing different wavelengths of light and reflecting others.
These pigments are divided into two categories primary (chlorophyll) and accessory (carotenoids) pigments. Chlorophyll is then divided into three forms a, b, and c (Campbell, 1996).
Chlorophyll a is the primary pigment used during photosynthesis (Campbell, 1996).
This pigment is the only one that can directly participate in light reactions (Campbell, 1996).
Chlorophyll a absorbs the wavelengths of 600 to 700 nm (red and orange) along with 400 to 500 nm (blue and violet) and reflects green wavelengths (Lewis, 2004).
Chlorophyll b has only a slight difference in its structure that causes it to have a different absorption spectra (Campbell, 2004).
The carotenoid involved with spinach leaf photosynthesis absorbs the wavelengths of 460 to 550 nm (Lewis, 2004).
The pigments are carotene and its oxidized derivative xanthophylls (Nishio, 2000).
A wavelength is determined by measuring from the crest of one wave to the crest of the next wave. All the wavelengths possible are grouped in a range called the electromagnetic spectrum (Campbell, 1996).
The range most important to life is from 380 to 750 nm (Campbell, 1996).
These wavelengths correspond to the wavelengths of visible light. Overall blue and red light works best, while green in least effective in the photosynthesis process (Nishio, 2000).
The wavelengths that a pigment absorbs, absorption spectra, are determined using a spectrophotometer. In order to obtain the photosynthetic pigment’s absorption spectra the pigments are separated using paper chromatography. Paper chromatography is an analytical technique that separates a mixture based on the individual pigment’s size, polarity and solubility (Lewis, 2004).
The separation of the mixtures involves a stationary phase (the chromatography paper), which a mobile phase (solvent) moves up through.
When the mixtures is applied to the paper and allowed to flow with the mobile phase, the different pigments move at different rates (Campbell, 1996).
This means the pigments that absorb the strongest to the stationary phase (the chromatography paper) will move the slowest, while the weakest will move the fastest. The rate of the pigments movement will separate each pigment individually from the mixture (Maitland, 2002).
The Term Paper on Light Wavelength Effect On The Photosynthetic Rate Of Elodea
Introduction: The rate of photosynthesis varies greatly with changes in wavelengths of light. Light’s colour is determined by its wavelength of light, and thus it is possible to devise an experiment to determine which wavelengths of light are most productive for photosynthesis than others. In this experiment I use a plant called Elodea (pond weed). Elodea is native to North America and it is ...
This natural separation shows that each pigment is chemically different and plays different roles in photosynthesis (Maitland, 2002).
To analyze the separated pigments a spectrophotometer is used to obtain an absorbance spectrum. This spectrum is a graph that shows a pigment’s light absorption versus wavelengths (Lewis, 2004).
The spectrophotometer quantitatively shows what fraction of light is passing through a given solution (Nishio, 2000).
A spectrophotometer works by shining a light of a known wavelength through a liquid sample. The light that passes through is measured with a light meter (photometer).
The greater the amount of pigment present, the more light will be absorbed, leaving less light to be detected by the photometer (Campbell, 1996).
It is the goal of this experiment to show that spinach has less ability to absorb green light than red light. The experiment will conclude that green lights has a low absorbency because green is not a vital component of photosynthesis while, red light will have a high absorbency due to its significant role in photosynthesis (Campbell, 1996).
This will be done using the proven method of paper chromatography to separate the pigments for analysis (Nishio, 2000).
The analysis of the pigments will be done using the spectrophotometer to give an absorbency spectrum that clearly indicates the absorption rates of green versus red light. Materials and Methods The light absorbency in spinach leaves was tested on 30 September 2003 using a Principles of Biology I (BIOG 161) class from Lorain County Community College. In order to complete this experiment the protocol from Karohl was followed (2003).
Due to the size of the class the individuals were divided into six groups for the chromatographic separation of the spinach pigments. The groups where then redrawn into five groups for the pigment analysis. Because of the cuvette’s being to long for the particular brand of spectrophotometer being used an individual from each group needed to hold down the cover while reading the absorbance scale. Results Once the chromatographic separation of the spinach pigment was concluded the chromatography paper was analyzed for the separation of the different photosynthetic pigments. Four distinct pigments where found. In order from the origin to the solvent front they are chlorophyll b (olive green), chlorophyll a (blue-green), xanthophylls (yellow) and carotene (yellow-orange).
The Essay on Light Plant Plants Green Red
Let There Be Light Introduction When we look at the sun, what do we see Other than to squint our eyes and put your sunglasses on, you can see that the light is very bright and white-yellow in color. However, looking at light through a prism relates a different story. If Light is put up against a prism it is refracted or bent into a rainbow which contains the primary colors of light in which red ...
Figure 1 shows how the bands where arranged and their colors. Figure 1: A drawing of the chromatography paper clearly showing the separation and colors of the photosynthetic pigments found in spinach leaves. Once all the groups where done with the analysis of the their pigment the where charted and then graphed out. The data (Table 1) was placed into a graph creating an absorbance spectrum (Figure 2).
The graph shows that the pigments peak in absorbency at the red and blue wavelengths, while dipping to a low absorbency rate during the green wavelengths. Discussion An absorption spectrum of the photosynthetic pigments show the different wavelengths of light an organism can use for photosynthesis (Campbell, 1996).
On the absorbency spectrum (see Figure 2) for this experiment one can see that red light had a better absorption rate than green light. The absorption rate indicates that red light is absorbed for photosynthesis while green light is transmitted giving the spinach leaves their green color. This is consistent with research on how chlorophyll a absorbs red and blue light the best, making these two colors vital to photosynthesis (Campbell, 1996).
Chlorophyll a and b have a significantly higher absorption rate indicating their primary role in photosynthesis (see Figure 2).
This is in line with the fact that chlorophyll a is the only pigment that can directly participate in light reactions (Campbell, 1996).
The carotene and xanthophylls absorbed a slightly different set of wavelengths allowing the plant to have a wider spectrum of colors it can use for photosynthesis (Campbell, 1996).
The data and earlier research concludes that spinach has less ability to absorb green light than red light. Table 1: This data shows specifically the range of absorbency rates for the individual photosynthetic pigments at different wavelengths.
The Essay on All About Light-Physics
LIGHT * Light is part of the electromagnetic spectrum, the spectrum is the collection of all waves, which include visible light, Microwaves, radio waves ( AM, FM, SW ), X-Rays, and Gamma Rays. * In the late 1600s, important questions were raised, asking if light is made up of particles, or is it waves .? * Sir Isaac Newton, held the theory that light was made up of tiny particles. In 1678, Dutch ...
Absorbance Spectrum of Spinach Pigment Extract Wavelength Chlorophyll a Chlorophyll b Xanthophyll Carotene Total Pigment 420 1. 3 0. 49 0. 42 0. 13 1.
1440 0. 525 0. 66 0. 55 0.
14 0. 86460 0. 14 0. 85 0. 44 0.
145 0. 7480 0. 08 0. 19 0. 46 0. 12 0.
41500 0. 045 0. 05 0. 06 0.
05 0. 142520 0. 06 0. 049 0.
01 0. 005 0. 09540 0. 06 0. 06 0.
01 0 0. 088560 0. 08 0. 065 0. 01 0 0.
09580 0. 125 0. 076 0 0 0. 111600 0.
15 0. 091 0 0. 005 0. 122620 0. 21 0. 09 0 0.
005 0. 148640 0. 24 0. 3 0 0.
005 0. 195660 0. 99 0. 18 0. 01 0. 01 0.
495680 0. 18 0. 03 0 0. 01 0.
09700 0. 03 0. 01 0 0 0. 028720 0.
01 0. 01 0 0 0. 02 Figure 2: The spectrum shows how absorbent the photosynthetic pigments are at different wavelengths of light. Note: Green light is between 500 to 570 nm and red light is between 630 to 720 nm.
References Campbell, N. A. , “Biology,” New York: The Benjamin/Cummings Publishing Company, Inc. , 1996, 182-200. Karohl, D. , “Principals of Biology I Laboratory,” Lorain, Lorain County Community College, 2003, 65-71.
Lewis, R. , “Life,” Boston: McGraw-Hill, 2004, 97-114. Nishio, J. N.
, “Why are higher plants green? Evolution of the higher plant photosynthetic pigment complement,” Plant, Cell and Environment, 2000, 23, 539-5.
