Effects of Sucrose Concentration On Cell Respiration In Yeast
Abstract
This lab investigates the effects of Sucrose concentration on cell respiration in yeast. Yeast produces ethyl alcohol and CO2 as a byproduct of anaerobic cellular respiration, so we measured the rate of cellular respiration by the amount of CO2 produced per minute. The results show a trend wherein increased concentrations of sucrose increase the rate of cellular respiration.
Introduction
All living cells require energy in order to proceed with cellular processes such as active transportation, and the synthesis of molecules. ATP (Adenine Tri-Phosphate) is a molecule, which provides energy in a form that cells can use for such cellular processes. Cellular
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In other words, higher sucrose concentrations should promote an increase in cellular respiration rates.
Materials
•4 Airline Tubes
•4 Syringes (No Needle)
•4 One-Holed Rubber Stopper
•4 Test Tubes
•4g Yeast (1g in each of the 4 test-tubes)
•3g Sucrose (varying amounts in each of the 4 test-tubes)
•140mL Warm Water (35mL in each of the 4 test-tubes)
•0.4g Salt (0.1g for each of the 4 test-tubes)
•Styrofoam test-tube holder
Procedure
I. Preparing The Gas Measuring Mechanism/ Make-shift Gas Syringe
1.Cut an airline tube about the length of your index finger. 2.Secure one end of the tube onto the tip of a needless syringe 3.Secure the other end of the tube into the hole located on the rubber stopper
II. Cell Respiration In Yeast
1.Measure and add 1g of yeast into 4 of the test tubes.
2.Measure and add 0.1g of salt into 4 of the test tubes.
3.Measure and add 0.5g, 1.0g, and 1.5g of sucrose into 3 of the test tubes. Do not add sucrose into the 4th test tube because this will be the control. Lightly shake the test tube to mix the contents together.
4.Measure 35mL of warm water and add them into each of the 4 test tubes at about roughly the same time. It is essential that the water is warm. Do not seal the test tube. 5.Wait 5 minutes. During these 5 minutes, set all 4 of the syringe plungers on the gas measuring mechanism at 2mL.
6. After 5
Next prepare the third test tube with an accurate measurement of 5ml sodium carbonate once again labelling appropriately.
In another test tube, put 1 mL of hamburger meal slurry. Repeat steps 2 and 3 with the hamburger meal slurry and record the results in Table 2.
We hypothesize that sucrose would have the highest respiration rate due to the fact that it is a disaccharide containing glucose and fructose, a combination of two sugar sources. The more sugar the S. cerevisiae is fed, the more CO₂ will be produced.
First I will set up the apparatus as show above. I will add 1.5 grams
In the standard protocol with only glucose and yeast, Figure 1 indicates that Tube 3 with the most yeast concentration has the greatest values, and tube 2 which has 1.4% yeast produces less CO2. From the data collected it can be concluded glucose and yeast is necessary in the production of , which agrees with the equation for glycolysis since glucose is the sugar that supplies the energy and yeast is the substance that performs the cycle. The higher concentration of yeast will result in more CO2since there is more substance to undergo glycolysis which produces CO2. As shown from Figure 1, the tubes that did not have any yeast or glucose resulted in no production of CO2 since they are missing factors to undergo glycolysis, and since they were
The type of sugar affects the rate of cellular respiration because each sugar is classified as either a monosaccharides, disaccharides or polysaccharides. The data from this experiment was collected by the amount of carbon dioxide produced from the type of sugar that was used. The data was then analyzed using a line graph. Data was also collected in class averages. There were three sugars in this experiment, glucose, lactose, and fructose. An example of a monosaccharides would be glucose and fructose. The slope for glucose should be about 283.07. The slope for fructose should be about 269.77. Second, an example of a disaccharides would be lactose. The slope for a disaccharide in this experiment should be about 67.055. The data shows that
1 ml of water should be added to the first test tube and make a note. In the second test tube, 1 ml of methyl alcohol should be added. In the third test tube, 1 ml of hexane must be added. Lastly, the fourth test tube will be a control.
Determining the effect of varying sucrose concentration on the rate of anaerobic cell respiration in yeasts
The research question that was investigated was: How does the concentration of sucrose affect the rate of cellular respiration carried out by yeast? This experiment allows information to be collected on the rate of cellular respiration of yeast based on a solution’s sucrose concentration.
Whereas the large molecule food (Sucrose) will take longer to break down because of its large molecules, this will waste the energy of the yeast as it has to break down the large molecules into smaller molecules before it can use them. This means that the sucrose is not as efficient as the glucose at providing the yeast with a better medium by which it will produce a faster rate of respiration. Theory:
The natural sugars used in this experiment will be lactose and glucose. The unnatural sugar that will be used is saccharin (an artificial sweetener). The rate of cellular respiration between the natural sugars will be compared to that of the unnatural sugar. Yeasts are unicellular organisms that belong to the fungi kingdom. Yeasts are known as facultative anaerobes; they can respire depending on the environment they are in. Yeast can metabolize sugars aerobically or anaerobically. In both cases, Carbon dioxide is produced.
Sucrose is made up of two simple sugars, glucose and fructose. While commonly used as table sugar, sucrose is important to all living organisms, including yeast. When yeast is introduced to sucrose, and does not have oxygen available to assist in respiration, it will resort to anaerobic respiration. This will involve the enzyme invertase to catalyze the hydrolysis of sucrose, as well as zymase to convert the hydrolyzed sugars to alcohol and carbon dioxide. When this happens in a sealed container, the carbon dioxide will become trapped gas. The ethanol actually inhibits the fermentation process, and results in the maximum concentration of ethanol solution of 10-15%.In this particular experiment, the density of the third fraction removed came
In this experiment the four different types of sugar substitutes will be tested with yeast to determine if the type of sugar substitute directly affects the respiration rate of yeast. The four different types of sugar substitutes include Saccharin (Sweet ‘N Low),
Table 2 revealed that the average respiration rate of glucose was the highest, followed by sucrose, water, lactose, and glycerol. Water does not have any carbon source for yeast to feed on, but it produced the third highest amount of carbon dioxide. From Table 2, the standard deviation revealed that glucose had an extremely high standard deviation, indicating that results were more varied, while water, lactose, and glycerol all had a significantly lower standard
Collect to 2 large beakers both large beakers are to be filled with hot water (labtutor). Then obtain seven conical tubes these will be used to collect the levels of gas, you will also need test tube a stopper and a plastic tube (labtutor). You want to fill the conical tube to at least 50 ml of water (Cressy). Take the four conical tubes filled with water and place two in each beaker, to do this you must invert the tube and cover the release hole as to not lose any water (Cressy). Then place the beakers with the tubes in the bath so they can be at the same temperature as the bath (Cressy). Next mark all of your test tubes in number order to be sure which tube contains what concentrations and pH (Cressy). Having mixed a solution to the specifications of 2.5 ml of glucose in all tubes, 3 ml of yeast in 2 tubes of pH 5, 2 tubes of pH 9, and the single pH 7 tube, the remaining two tubes will contain no yeast as they will be negative controls. Next add 2 ml of pH buffer 3 tubes will receive pH of 5, three will receive a pH of 9 and a single tube of pH 7. Finally add pure water to make sure all test tubes have 10 ml of solution. When making the solutions