BIO Photosynthesis Lab.docx - Elena Scott BIO 111-539...

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Elena ScottBIO 111-539Assignment #6Assignment #6: PhotosynthesisPhotosynthesis: Effect of Light Intensity, Light Wavelength, and the Activity of Photosynthetic PigmentsAbstract: This experiment is performed to observe the different characteristics of photosynthesis. The light intensity was measured by observing and comparing four tubes that had different light intensities. The action spectrum was used to test the effect of red, blue, green, white, and no light on photosynthesis. The activity of photosynthetic pigments determined which wavelengths of light were used for photosynthesis. This was done by determining the pigments found in starch through silica gel chromatography and determining the absorbance of each pigment at different wavelengths. Higher photosynthesis occurred when light intensity increased, and white light was found to be the most effective light used in photosynthesis. The experiment for absorption spectrum proved that the wavelengths of chlorophyll a and chlorophyll b absorb more than other lead pigments because they are more directly involved in the process of photosynthesis. In conclusion, light intensity and light wavelength affect the rate of photochemical reactions. Introduction: The purpose of this experiment is to test the effect of light intensity, light wavelength, and the activity of photosynthetic pigments on photosynthesis. Used by plants, algae, and certain bacteria, the process of capturing energy from sunlight and turning it into chemical energy is called photosynthesis (Vidyasagar). The effects of photosynthesis can be observed through several experiments, such as: light intensity, action spectrum, and absorption spectrum. Experiment #1 – Light Intensity:Hypothesis: as light intensity is increased, the excitation of the chlorophyll molecules is increased, resulting in higher photosynthesis. Null hypothesis: as light intensity is increased, the excitation of the chlorophyll molecules is not affected.Experiment #2 – Action Spectrum:Hypothesis: spinach leaf disks under red light will have the highest rate of photosynthesis. Null hypothesis: light does not play a role in photosynthesis of plants. Experiment #3 – Absorption Spectrum:Hypothesis: the wavelength of chlorophyll a and chlorophyll b will absorb more than the other leaf pigments because they are more directly involved in the process of photosynthesis. Null hypothesis: there is no correlation between the measured rate of photosynthesis and the absorption frequencies of chlorophyll a and chlorophyll b. Methods: Experiment #1 – Light Intensity:This experiment was initiated by turning on the spectrophotometer and setting the wavelength to 605 nm (Lab Manual).

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