Elodea Lab Report

Figure one demonstrates that when light intensity increases, there is an increase in oxygen. This occurs due to lights effect on the photosystem II ability to transfer electrons and hydrogen ions from water to NADP+. An increase of light, increases the rate of water splitting within the chloroplasts, producing the O2 by-product. (Reece, et al, 2015) (Ping et al, 2015)

Organisms that use the process of photosynthesis to create sugar to use for energy have a greater rate of photosynthesis when the intensity of the light source is the greatest. If light is far away from the leaves of a plant, for example, then it takes more time for the light to be absorbed and used in photosynthesis. When it takes more time for the light to reach the leaves, the rate of photosynthesis decreases. As the light intensity increases, I would expect the rate of photosynthesis to increase as well. Therefore, I would expect that when the Elodea is closest to the light bulb, the rate of photosynthesis would be the greatest. My hypothesis would be: If light intensity affects the rate of photosynthesis, and the rate of photosynthesis is measured using the amount of

Today with my group lab we had to discuss on how to design an experiment that investigated the two herbicides DCMU and DCPIP. We used Elodea leaf and Elodea is basically a genus of aquatic plants often called the waterweeds and can be found anywhere in a pond or under water. So we started by creating a solution of phenol red, by adding 5 drops of concentrated phenol red to 40mL of water, then one of our group member used a straw to gently blow air into the solution until it reaches a neutral pH. We then transferred the solution into two test tubes evenly and labeled each tube dark and light, meaning the dark one will stay in the dark and the light one will stay under light bulbs. We predicted that dark one will stay the same and the light

When we looked under the microscope to observe elodea under different circumstances, it was made clear that something was happening as we added sugar to the leaf. The insides of the elodea leaf cells became “smaller.” Those small green structures inside the cells that were tightly packed to the cell wall are called chloroplasts. When a sugar-water solution was dropped onto the elodea leaf, the chloroplasts began shrinking and the gap between the plasma membrane and the cell wall increased. The process is known as plasmolysis. In order to prove that sugar “shrunk” the inside the of the cells, we had to set up a controlled experiment. The basic idea of the experiment was

Test tube six contained an elodea and was placed in the dark. It was hypothesized that, after a day, the test tube would be yellow in color. Upon observing, the hypothesis was proven correct because test tube six had remained yellow. This is because the elodea was placed in the dark where it could not receive light to photosynthesize and remove carbon dioxide from the

Abstract: An experiment was carried out to determine how certain factors such as light intensity and availability of carbon dioxide, affected the rate of photosynthesis. The rate of photosynthesis was measure by the amount of oxygen produce (cm3/min).

The Effect of Light on Carbon Dioxide Exchange in Elodea Background- The purpose of this lab is to find out what effect light has on absorption and release of carbon dioxide in Egeria densa, better known as Elodea. This research can be used to see what effect plants have on carbon dioxide. The belief is that when light is present then carbon dioxide will be absorbed and when light is not present then carbon dioxide will be released.

Photosynthesis and cell respiration are some of the two most important biological processes that organisms go through. Photosynthesis is the biological process plants undergo to convert light energy into chemical energy. In chloroplasts the chlorophyll act as catalysts for this process. The process uses carbon dioxide (CO2) and Water (H2O) in order to produce glucose (C6H1206) and oxygen (02). Thus, it is read as 6CO2 + 6H2O —> C6H12O6 + 6O2. Photosynthesis is split into two different processes. The first process is light Dependent meaning i uses energy being absorbed to break down and molecules at a rapid photosynthetic rate. The second process is Light Independent meaning it uses ATP and NADH absorbed during when light was present to breakdown glucose instead. Therefore, Healthy plants are green because Chlorophyll absorbs red and blue light, but reflects green light signifying stored light.Some Anaerobic bacteria undergo photosynthesis meaning it can’t grow in oxygen and uses Carbon Dioxide and other substances like hydrogen sulfide to photosynthesis. In general all plants need Carbon Dioxide. (Ensminger, 2014)

Photosynthesis is a vital process that requires to utilize energy for plants. This experiment was done to evaluate the effects of carbon availability on photosynthetic activity. The aquatic plant Elodea densa was placed into sodium bicarbonate solutions of five concentrations ranging from 0.1% to 1.0%, in five independent trials (excluding the negative control treatment of water). The temperature and light intensity was constant. The results indicated a directly proportional relationship between the availability of carbon dioxide and the rate of photosynthesis of Elodea Densa, as photosynthesis continued to increase with increasing amounts of bicarbonate. The most O2 amount of oxygen produced was with the 0.7% NaHCO3 concentration and least with the control of water. The null hypothesis that stated carbon concentration does not affect rate of photosynthesis of the aquatic plant was rejected. The predicted hypothesis that an increase in bicarbonate concentrations results in an increase in the photosynthetic rate was accepted. In conclusion, there is a significant increase in photosynthetic activity as the concentration of NaHCO3 increases.

Qualitative Raw Data It was observed that as the temperature of the water increased, the number of oxygen bubbles produced by the Elodea did as well, however the number decreased after passing its optimal temperature, thus supporting the hypothesis made. For some of the trials in the experiment, in particular for the higher temperatures, there was no data recorded for the first 10 seconds. Afterwards, however, oxygen bubbles were produced in quick succession for a short period before slowing down again. This suggests that there may have been a blockage in the inside of the xylem or phloem vessels in the Elodea after cutting the stem.

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.

Aerobic respiration is the intake of glucose and oxygen and the production of CO2 and ATP, heat, and water. This experiment was conducted to show whether saran wrap can have an effect on the aerobic respiration of the aquatic plant, Elodea. For example, whether it will increase it or decrease it. By recording the amount of drops of 0.02N NaOH it took for the water to turn a certain shade of pink, we were able to determine the amount of CO2 that was present. Thus we were able to tell what effect sealing the beakers with saran wrap had on Elodea. We sealed two beakers, one with elodea and one without. Two other beakers were not sealed, one had the plant and one also did not. the results showed that there was no significant difference in the amount of CO2 that was present in the beakers sealed with saran wrap irrespective to having a plant in the water or not. A reason for this this result might be that the incubation period was not long enough for actual, significant results to occur.

However, the photosynthetic process can be affected by different environmental factors. In the following experiment, we tested the effects that the light intensity, light wavelength and pigment had on photosynthesis. The action spectrum of photosynthesis shows which wavelength of light is the most effective using only one line. The absorption spectrum plots how much light is absorbed at different wavelengths by one or more different pigment types. Organisms have different optimal functional ranges, so it is for our benefit to discover the conditions that this process works best. If the environmental conditions of light intensity, light wavelength and pigment type are changed, then the rate of photosynthesis will increase with average light intensity and under the wavelengths of white light which will correspond to the absorption spectrum of the pigments. The null hypothesis to this would be; if the environmental conditions light intensity, light wavelength and pigment type are changed, then the rate of photosynthesis will decrease with average light intensity and under the white light which will correspond to the absorption spectrum of the pigments.

The purpose was to determine how levels of light affect photosynthesis. This was done by placing portions of a green plant in a bromothymol blue solution and observing the colour changes that occurred. It was determined that plants exposed to light produce far more oxygen than those placed in a dark environment. This confirms the hypothesis that oxygen is necessary for continued photosynthesis. Grade 12 University Biology, SB14U, Rockland District High School Wednesday May 11th, 2016

     To metabolic pathways involved in photosynthesis are light reaction and dark reaction. The first stage of the photosynthetic system is the light-dependent reaction, which converts solar energy into chemical energy. Light absorbed by chlorophyll or other photosynthetic pigments is used to drive a transfer of electrons and hydrogen from water to and acceptor called NADP , reducing it to the form of NADPH by adding a pair of electrons and a single proton. The water or some other donor molecule is split in the process. The light reaction also generates ADP, a process called photophosphorylation. ATP is a versatile source of chemical energy used in most biological processes. The light reaction produces no carbohydrates such as sugars.