Cellular respiration and fermentation - Lab Report Example

Cellular Respiration and Fermentation Table of Contents Abstract 2 Paper Proper 2 Introduction 2 Materials and Methods 2 Results 4 Conclusions 4 References 8 Abstract The two-part experiment involved tracking fermentation and respiration processes making use of carbon dioxide markers in gas height and in the production of carbonic acid respectively (ASPB Foundation n.d.; Nuffield Foundation 2013; The Regents of the University of California 2011).. Paper Proper Introduction The goal of the experiment is to investigate respiration and fermentation reactions. Studying fermentation and respiration as done in this experiment has implications for industry, as fermentation reactions, for one, impact the way we produce an important industrial product for instance, in this case ethanol. The nature of the sugar matters too, as the use of particular kinds of sugars in ethanol production, to use the same example, affect the amount of products that are produced in such reactions (Gore et al. n.d.; Bacon 1953; Nuffield Foundation 2013; The Regents of the University of California 2011). In the first part, fermentation is measured using gas height as proxy for carbon dioxide measure and the rate of reaction. In the second part, respiration is measured in terms of carbonic acid production. (ASPB Foundation n.d.; Nuffield Foundation 2013; The Regents of the University of California 2011). Materials and Methods The key materials used are the following: 10 percent sucrose solution; 10 percent glucose solution; peas; distilled water; phenol red; yeast stock; wax pencil; water bath; hot plate; test tubes of various sizes; beaker; test tube corks and holders; test tube rack. The idea behind the test tubes of varying sizes is to create a respirometer using two sizes of test tubes, for the experiment involving the yeasts. A practice session involves filling the smaller tube, measuring 15 x 125 mm with water, placing that inside a 20x150 mm test tube, and inverting to the point where the air bubble in the smaller test tube is as small as can be made from the process. In the actual experiment, three different test tubes are filled with two thirds of either ten percent sucrose solution, ten percent glucose solution, or distilled water, and then topped off to the brim with yeast suspension. The inversion method practiced above is utilized to mix the solutions and form the respirometers. The respirometers are allowed to incubate for one hour, while placed in a water bath set at 37 degrees Celsius. The gas bubble heights are measured after the period of incubation. The idea is to be able to undertake a comparison of how the three sources of food in the test tube compare with regard to their suitability as food for yeast. This is the first part of the experiment (Experiment 7 n.d., pp. 59-61). In part two of the experiment, 10 peas that were either soaked, not soaked, and soaked and boiled were placed in each of three different test tubes, filled with water up to the two-thirds level, and covered with corks. After an hour and a half, two drops of phenol red were placed in each of the three test tubes containing the seeds, more when no color was visible or the color is too vague/thin. The results of the color observations were tabulated. (Experiment 7 n.d., pp. 59-61) Results The first part of the experiment measured the amount of respiration from the fermentation process, involving the yeast solution and the three food sources. Among the three food sources, the glucose solution had the highest change in the gas height at the end of the incubation period, with the gas height changing from the initial 1 mm to 6 mm. The sucrose solution had a lower gas height change, going from 1 mm initially to 4 mm at the end of the observation period. The test tube containing just distilled water showed no change in the gas height, indicating that no respiration took place. In the second part of the experiment, the setup containing the soaked beans had a yellow color, while the setup containing the beans that were both soaked and boiled remained red, the same color as the phenol red placed. The setup containing the unsoaked beans showed some changes in color to yellow when some phenol red was mixed to it (Experiment 7 n.d., pp. 59-61). Conclusions The first part of the experiment involving respiration for fermentation reactions showed that among the three food sources, it is glucose that yields the greatest amount of generated carbon dioxide. We know that carbon dioxide is the generated gas owing to the nature of the reaction when yeast is added to glucose. In the classic equation the fermentation reaction yields not just carbon dioxide but also ethanol. In word form the reaction equation is glucose → ethanol + carbon dioxide. In equation form this is the same as (Tiscall 2013; Schuster et al. 2005; The Regents of the University of California 2011): Equation Source: The Regents of the University of California 2011 In the reaction above, yeast is the cause of the reaction, and glucose is broken down into carbon dioxide and ethanol. This is a very basic reaction that has industrial uses, in that in many production processes it is this reaction that is used to produce the ethanol needed for various other uses (The Regents of the University of California 2011). Within the yeast the active enzyme that catalyzes the reaction is known as zymase (Gore et al. n.d.; Bacon 1953; Nuffield Foundation 2013; The Regents of the University of California 2011). In the sucrose solution on the other hand, the lower change in the gas height indicates a lower level of production of carbon dioxide in comparison to the glucose. This implies that there is a lower rate of reaction as far as the production of the gas is concerned. This is due to the fact that sucrose has to be first broken down by the yeast enzyme invertase before the broken-down simple sugars can be used to produce ethanol and carbon dioxide. This is a two-step reaction that results in a lower amount of carbon dioxide being emitted, the latter process being less efficient and more time-consuming (Gore et al. n.d.; Bacon 1953). In the second part of the experiment, the goal was to determine respiration processes for seeds that were either soaked, not soaked, or soaked and boiled, The boiled peas did not respire at all, indicating that they are dead. The soaked seeds had the greatest amount of carbon dioxide respired, owing to its reaction with phenol red, where the water , which had become a weak acid with the respired carbon dioxide, reacted with the phenol red to become yellow. The resulting solution is known as carbonic acid, and the equation for this reaction is given below (ASPB Education Foundation n.d.): . Equation Source: ASPB Foundation n.d. The carbonic acid reacted with the phenol red also in the unsoaked seeds, but owing to the lower level of the respiration, only a small amount of the acid was generated, and therefore the reaction with phenol red was difficult to detect. The change in color was subtle. In the boiled seeds, no respiration took place, and therefore there was no change in the acidity of the water (ASPB Foundation n.d.). The two experiments taken together tell us that respiration processes and fermentation processes are similar in that both have carbon dioxide involved of the processes. In the respiration process the carbon dioxide is the respired gas. In the fermentation process involving glucose carbon dioxide is the byproduct of the reaction that mainly results in the conversion of glucose into ethanol. In the fermentation experiment the proof of the fermentation is the height of the gas. In the respiration experiment it is the conversion of the water to weak carbonic acid that is the proof of the respiration (ASPB Foundation n.d.; Nuffield Foundation 2013; The Regents of the University of California 2011). References ASPB Foundation n.d.. Plants Respire Too [Online] Available at: http://www.aspb.org/education/12Labs/labs/05_Respiration%20and%20energy.pdf [Accessed 7 March 2013] Bacon, JSD 1953. The Oligosaccharides Produced by the Action of Yeast Invertase Preparations on Sucrose. University of Sheffield. [Online] Available at: Gore, Jeff et al. n.d.. Cooperation in yeast sucrose metabolism. MIT. [Online] Available at: http://q-bio.org/w/images/5/51/Poster08-gore.pdf [Accessed 7 March 2013] [Accessed 7 March 2013] Gore, Jeff et al. n.d.. Cooperation in yeast sucrose metabolism. MIT. [Online] Available at: http://q-bio.org/w/images/5/51/Poster08-gore.pdf [Accessed 7 March 2013] Nuffield Foundation 2013. Fermentation of glucose using yeast. Nuffield Foundation. [Online] Available at: http://www.nuffieldfoundation.org/practical-chemistry/fermentation-glucose-using-yeast [Accessed 7 March 2013] Regents of the University of California 2011. Ethanol production by yeast fermentation. UCSB Chemical Engineering. [Online] Available at: http://www.chemengr.ucsb.edu/ [Accessed 7 March 2013] Schuster, Tom et al. 2005. Effect of Different Isomers of Sugar on Yeast Respiration. California State University Northridge. [Online] Available at: http://www.csun.edu/scied/2-longitudinal/schuster/index.html [Accessed 7 March 2013] Tiscall 2013. fermentation. TalkTalk. [Online] Available at: http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0008008.html [Accessed 7 March 2013] Read More