Photosynthesis is a vital process used by plants, some protists, and cyanobacteria in which the light energy coming from the sun is transformed into chemical energy. Chemical energy, then, can be used for cellular processes and stored in the form of glucose, which is essential for life on earth since it fuels the metabolic process of cells (Morris & Moat, 2016, p.227). The purpose of this experiment is to separate and analyze photosynthetic pigments and determine the absorption spectrum of spinach leaves.
The process of photosynthesis can be shown by the following equation:
6CO2 + 6H2O + light C6H12O6 + 6O2
Photosynthesis occurs in a series of steps. First, the needed carbon dioxide enters a plant’s leaves through the pores in the
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This organelle contains several photosynthetic pigments that absorb light energy such as chlorophyll, which are the primary pigments involved in photosynthesis, and carotenes and xanthophylls. Photosynthesis would not be able to work if plants would not have such pigments. Each different pigment reflects a certain color of light and absorb other colors. The function and color absorption of each pigment is summarized in the table below.
Plant Pigment Function Color Absorption Color reflection
Chlorophyll a Principal chlorophyll; plays a significant role in the photosynthesis Blue-violet and red light Dark green
Chlorophyll b Transfers the light energy it absorbs to chlorophyll a Blue and orange light Light green
Carotenes Increase the overall absorbance of light energy by absorbing light that is not absorbed by the chlorophylls Mainly absorb blue-green light Orange
Xanthophylls
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Record this data in the Rf values table. Place the chlorophyll a (blue-green) from the chromatography paper into a small beaker and add 10 ml of acetone. Stir the mixture to dissolve chlorophyll a. Fill a cuvette with the dissolved chlorophyll A, and another cuvette with pure acetone. The cuvette with pure acetone will be used as the “blank”. Turn on the spectrophotometer Measure the absorbance of the chlorophyll a from 380 nm to 720 nm in an increment of 20 nm. Record the results in the Absorption Spectrum of Chlorophyll a table.
Careful note: Pour all of the liquids used in this experiment in a fume hood.
Results
Unfortunately, I was not able to attend to lab the day this experiment was conducted. However, if I would have, I would have plug the data found by measuring the paper chromatography in the table below. Moreover, I would have also plug the data from the spectrophotometer on the table in the next page.
Plant Pigment Distance traveled by pigment Distance traveled by solvent Rf Color
Chlorophyll a N/A N/A N/A Dark green/blue
Chlorophyll b N/A N/A N/A Light green
Carotenes N/A N/A N/A Orange red
Xanthophylls N/A N/A N/A
The hypothesis for this experiment was that the cell fraction in the cuvette marked P2 will have more chloroplast activity because it will exhibit greater color change and differences in the absorbance readings compared to the other cuvettes when exposed under the condition of light; moreover, this notion was believed to be so because the more a cell fraction is centrifuged, the more intact chloroplasts we’ll find (Leicht and McAllister,
The high rate of absorbance change in blue light in the chloroplast samples (Figure 1) can be attributed to its short wavelength that provides a high potential energy. A high rate of absorbance change is also observed in red light in the chloroplast samples (Figure 1), which can be accredited to the reaction centre’s preference for a wavelength of 680nm and 700nm – both of which fall within the red light range (Halliwell, 1984). Green light showed low rates of photosynthetic activity and difference in change in absorbance at 605nm in the chloroplast samples (Figure 1) as it is only weakly absorbed by pigments, and is mostly reflected. The percentage of absorption of blue or red light by plant leaves is about 90%, in comparison to the 70–80% absorbance in green light (Terashima et al, 2009). Yet despite the high absorbance and photosynthetic activity of blue light, hypocotyl elongation was suppressed and biomass production was induced (Johkan et al, 2012), which is caused by the absorption of blue light by the accessory pigments that do not transfer the absorbed energy efficiently to the chlorophyll, instead direction some of the energy to other pathways. On the other hand, all of the red light is absorbed by chlorophyll and used efficiently, thus inducing hypocotyl elongation and the expansion in leaf area (Johkan et al, 2012).
Both starch and sucrose can be converted back into glucose and used in respiration. Photosynthesis happens in the mesophyll cell of leaves. There are two kinds of mesophyll cells - palisade mesophyll and spongy mesophyll. The mesophyll cells contain tiny bodies called chloroplasts which contain a green chemical called chlorophyll.
Experiment #1: The purpose of this experiment is to investigate the effects of baking soda and light intensity on the rate of photosynthesis of green spinach leave through the observation of floating disk.
The process of photosynthesis is present in both prokaryotic and eukaryotic cells and is the process in which cells transform energy in the form of light from the sun into chemical energy in the form of organic compounds and gaseous oxygen (See Equation Below). In photosynthesis, water is oxidized to gaseous oxygen and carbon dioxide is reduced to glucose. Furthermore, photosynthesis is an anabolic process, or in other words is a metabolism that is associated with the construction of large molecules such as glucose. The process of photosynthesis occurs in two steps: light reactions and the Calvin cycle. The light reactions of photosynthesis take place in the thylakoid membrane and use the energy from the sun to produce ATP and NADPH2. The Calvin cycle takes place in the stroma of the chloroplast and consumes ATP and NADPH2 to reduce carbon dioxide to a sugar.
The substance that absorbs sunlight is chlorophyll, which is mainly contained in chloroplasts. This energy is used to convert carbon dioxide (CO2) and water into sugars. This conversion creates the waste product oxygen, which is used by humans for breathing. Without being able to photosynthesise plants will stop growing and die. In a plant growing in the dark the chlorophyll will slowly be destroyed causing them to use their food reserves.
[IMAGE]Carbon dioxide + water Light Energy glucose + oxygen Chlorophyll [IMAGE]6CO2 + 6H20 Light Energy C6 H12 O6 + 6O 2 Chlorophyll Photosynthesis occurs in the leaves of the plant in the palisade layer. Chlorophyll in the cells in the palisade layer absorb light for photosynthesis. The plant releases the oxygen created in photosynthesis back into the air but it uses or stores the glucose for energy, respiration, growth and repair. The leaves and plants are also specially adapted for photosynthesis in their structure and cell alignment. Preliminary Experiment Apparatus * Piece of Elodea Canadensis * Bulb * Voltmeter * Test tube * Beaker * Box *
A cuvette was filled 3/ 4ths of the way and the absorbance measured in a spectrophotometer. The data was compiled as a class and recorded. The Spectrophotometer was blanked using a test tube of distilled water.
Photosynthesis in simpler turns is the ability of a live plant to carry on its chemical process by the use of light energy. Photosynthesis can not take place when there is absolutely no light, instead it stores the light it captures during the day, and uses it when needed. Photosynthesis can take place in land plants and aquarian plants such as algae. There are many factors that influence the ability of a plant to go through photosynthesis, such as light, the color of light and amount of water and or light.
Increasing the light intensity will make photosynthesis faster. Variables: In this experiment there are a few things we have to keep the same.
The structure of chlorophyll involves a hydrophobic tail embedded in the thylakoid membrane which repels water and a porphyrin ring which is a ring of four pyrrols (C4H5N) surrounding a metal ion which absorbs the incoming light energy, in the case of chlorophyll the metal ion is magnesium (Mg2+.) The electrons within the porphyrin ring are delocalised so the molecule has the potential to easily and quickly lose and gain electrons making the structure of chlorophyll ideal for photosynthesis. Chlorophyll is the most abundant photosynthetic pigment, absorbing red and blue wavelengths and reflecting green wavelengths, meaning plants containing chlorophyll appear green. There are many types of chlorophyll, including chlorophyll a, b, c1, c2, d and f. Chlorophyll a is present in all photosynthetic organisms and is the most common pigment with the molecular formula C55H72MgN4O5. Chlorophyll b is found in plants with the molecular formula C55H70MgN4O6, it is less abundant than chlorophyll a. Chlorophyll a and b are often found together as they increase the wavelengths of light absorbed. Chlorophyll c1 (C35H30O5N4Mg) and c2 (C35H28O5N4Mg) are found in algae, they are accessory pigments and have a brown colour. Chlorophyll c is able to absorb yellow and green light (500-600nm) that chlorophyll a
Photosynthesis is a process in plants that converts light energy into chemical energy, which is stored in bonds of sugar. The process occurs in the chloroplasts, using chlorophyll. Photosynthesis takes place in green leaves. Glucose is made from the raw materials, carbon dioxide, water, light energy and oxygen is given off as a waste product. In these light-dependent reactions, energy is used to split electrons from suitable substances such as water, producing oxygen. In plants, sugars are produced by a later sequence of light-independent reactions called th...
This is the same if there is the light intensity is too high as this can damage the chloroplasts in plants and this will minimize the rate of photosynthesis. As shown in the graph as the light intensity increases, the photosynthesis rate increases until a point is reached where the rate begins to level off into a plateau. At a low light intensity, photosynthesis occurs slowly because only a small quantity of ATP and NADPH is produced. As the light intensity shown in the graph is gradually increasing, more ATP and NADPH (NADH is used in cellular respiration and NADPH is used in photosynthesis) are produced, which means more oxygen and sugar is produced, therefore increasing the rate of photosynthesis. But as the light intensity increases even more and past a certain light intensity on the graph, this is due to the other factors such as carbon dioxide limiting the rate of
Begin collecting samples with the pure hexane. Keep adding hexane so that the silica gel column does not run dry. Collect one 20 ml sample. Repeat with 90:10 hexane and collect 4 20-mL bottles. Repeat with 80:20 hexane and collect 2 20-mL samples.
however it does not easily absorb green or yellow light, rather it. reflects it, this decreases the rate of photosynthesis. This can