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The effect of temperature on the rate of yeast fermentation
The effect of temperature on fermentation
Effect of enzyme concentration on enzyme kinetics
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Yeast Respiration Experiment
Temperature (°C)
[IMAGE]Number of Bubbles
10
0
20
14
30
17
40
17
50
19
60
24
70
35
80
48
Data Analysis and Conclusion
The data shows a clear rise in yeast respiration as the temperature is
raised. Although an optimum temperature is not evident, it can be seen
that temperatures exceeding 60°C speed up the reaction. This shows the
general rule that reactions become faster when the temperature is
increased. Unfortunately this data does not seem to show an optimum
temperature for the enzymes in the yeast to function properly, which
would be expected normally.
There are several weaknesses that would have definitely decreased the
accuracy of the experiment by a noticeable amount.
Firstly, the temperature of the yeast itself probably would not have
been equal to the temperature stated on the thermometer. The
thermometer was in the beaker of water, adjacent to the flask, but the
amount of time given for the yeast to equalize temperature to the
water temperature may have been too short. A thermometer actually
going through the cork into the flask through its cork would have
provided much more accurate temperature readings, and therefore a more
accurate experiment.
Secondly, the expansion of the air in the flash due to its heating up
was not taken into account. As the temperature increased, the
expansion would have been constant, but when the actual CO2 from the
yeast was produced, we were unable to determine what was actually
coming from the yeast. If there was a predetermined amount of air in
the flask and tube, and its expansion was taken into account, this
would have helped make the experiment more accurate.
Thirdly, no control was used in the experiment to make reference to. A
flask filled with water (to the same volume as the yeast) would have
provided sufficient control on the experiment.
In addition, the data points were quite far apart. Having more intermediate data points would have enabled the scientists to more accurately model the continuous nature of the data with a discontinuous series of points. Finally, stopping the flask more quickly would have allowed less gas to escape. Using a mechanical solution that could stop nearly instantly would have been ideal.
3. The time taken for the yeast to heat up to the temperature of the
The Effect of Temperature on the Rate of Respiration in Yeast There are two types of respiration in yeast: Aerobic: [IMAGE] Anaerobic: Glucose [IMAGE] Carbon dioxide + ethanol + energy Respiration is controlled by enzymes, which are proteins which speed up one or more biological reactions. Within any cell many chemical reactions are going on at any one time. Yeast has many different types of enzymes that speed up respiration. Prediction I predict that as temperature increases, the rate will also increase, until a certain optimum temperature, after which, the rate will decrease until the rate is zero as respiration has stopped completely. Reason
--------------------- There are many ideas to suggest that the change in temperature will cause an increase of respiration in yeast. Yeast is a single cell fungus made up mostly of protein, which has been use for its applications in fermentation. Yeast, after activation creates the ferments carbon dioxide and ethyl alcohol by secreting the enzyme zymase (a complex of 12 enzymes) in the yeast, which acts on simple sugars such as glucose. The alcohol produced has been used in making wines and bears and the carbon dioxide produced has been used in baking as it gets trapped in the dough and causes it to rise. Enzymes are catalysts which speed up reactions, they are made from protein and are specific as to which substrate they work on.
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The purpose of this investigation is to test the effects of multiple sugar substances on the respiration of yeast. Most people think of yeast when they think of what makes bread rise, cheese, alcoholic beverages, or other food products. Another type of yeast can also cause yeast infections, an infection of the skin. Yeasts (Saccharomyces) are tiny, microscopic organisms with a thin membrane and are usually oval or circular-shaped. They are a type of single-celled fungi of the class Ascomycetes, capable of processing sugar into alcohol and carbon dioxide (CO2 ) ; this process is known as fermentation. Fermentation and the products are the main focus points for this experiment being that cellular respiration of yeasts happens via the process of fermentation, which creates by-products of alcohol and CO2. The level of CO2 produced by the yeasts will show how effective each sugar substance is in providing cellular energy for the yeasts.
= I predict that if the concentration is high in the yeast then the speed of oxygen produced in the reaction with hydrogen peroxide will also be high. This is because the amount of yeast that can react with the hydrogen peroxide can get no higher and will have the maximum affect on the reaction. If the concentration is more in favour of water then the amount of oxygen produced will be slow because there is not as much yeast to react with the hydrogen peroxide, giving less oxygen. If the temperature is not in favour of the limits to the yeast then the amount of oxygen produced will be small because the enzyme will have denatured. If the temperature is in favour of the yeast then the amount of oxygen produced will be high because it is at the prime temperature for the yeast to react.
The Effect of Temperature on the Rate of Respiration in Yeast I have chosen to investigate the affect temperature has on the rate of respiration in yeast. I will use an experiment to determine whether the yeast's rate of respiration will be quicker, slower or if it does not change when the temperature is varied. Scientific Knowledge The first thing to say about enzymes is that they are proteins and they are found in all types of organisms from humans to viruses.
The results shown in table 1 clearly show that when the volume of yeast is increased in the milk solution, so does the rate of oxygen depletion and therefore the rate of eutrophication. It shows that when 2mL of yeast solution was added it took 32.86 minutes on average for the milk to be depleted of oxygen, while it took only 7.46 minutes on average for the 10mL of yeast to use up the oxygen present.
Experimental Summary: First, my partner and I put the marshmallow and cheese puff on T-pins and used the Electronic Balance to measure the mass of each of them. Next, we put 100 mL of water in the 100 mL Graduated Cylinder and poured it into the 12 oz. soda can. We measured the temperature of the water with the thermometer. After
In Cellular respiration, glucose enters the body and is broken down by glycolysis. For prokaryotes, cellular respiration is performed in the cytoplasm or inner surfaces of the cell, while eukaryotes perform it in in the mitochondria. In Glycolysis, a process in the cytosol, two ATP are invested to produce two pyruvates, two water molecules, four ATP, two NADH and two hydrogen ions. Following glycolysis is Pyruvate oxidation, which oxidizes the pyruvates from glycolysis to acetyl CoA and NAD+ to NADH+H+ and a CO2 waste. After pyruvate oxidation is the Kreb’s cycle, which occurs in the mitochondria. This cycle oxidizes Acetyl
= In this experiment the temperature shall affect the way in which yeast respires. The snares are. I predict that the temperature at which the rate of reaction shall be fastest at higher temperatures but below 50oC. This is because enzymes work best at the higher temperatures. If the temperature is above around 50oC enzymes break down and stop working.
There is also the potential of human error within this experiment for example finding the meniscus is important to get an accurate amount using the graduated pipettes and burettes. There is a possibility that at one point in the experiment a chemical was measured inaccurately affecting the results. To resolve this, the experiment should have been repeated three times.
There were five test solutions used in this experiment, water being the control, which were mixed with a yeast solution to cause fermentation. A 1ml pipetman was used to measure 1 ml of each of the test solutions and placed them in separated test tubes. The 1 ml pipetman was then used to take 1ml of the yeast solution, and placed 1ml of yeast into the five test tubes all containing 1 ml of the test solutions. A 1ml graduated pipette was placed separately in each of the test tubes and extracted 1ml of the solutions into it. Once the mixture was in the pipette, someone from the group placed a piece of parafilm securely on the open end of the pipette and upon completion removed the top part of the graduated pipette.
Yeast is used everyday for many purposes. Unless you don’t eat bread or drink alcohol, you have plenty of yeast in day to day life. It brings important characteristics to lots of foods, such as the bubbling in alcoholic beverages and the rising of bread. Yeast can also be related to infections. The question is, what happens to yeast when exposed to varying different levels of salt, and how does this affect its cellular respiration process?