Yeast Investigation
Introduction
In this investigation I am going to try and find the optimum
temperature at which the new strain of yeast respires using trial and
improvement. I will test from 20°c to 70°c as this is the most
suitable. This means that little heating will be needed to get the
maximum respiration in the yeast and therefore the most efficient
alcohol production. Yeast respires glucose an aerobically producing
carbon dioxide and ethanol as waste products. The carbon dioxide is
given off as bubbles and the number given off in a certain amount of
time can be used to estimate the rate of reaction. I will be using
this method in my experiment.
Method
To do this investigation I will test the yeast in a water bath (beaker
filled with water of a certain temperature) so I can adjust the
temperature and mix the yeast with water using a syringe and some
tubing. I will be using 250ml of water, 25g of sucrose (sugar) and 2g
of dried yeast. I will also use tin foil wrapped round the beaker to
keep the temperature from changing.
Fair Test
I will make this experiment a fair test by using the same water bath
syringe and tubing each time and by measuring the water sucrose and
yeast very carefully.
Prediction
I predict that the optimum temperature will be around 20°c as yeast
respires glucose an aerobically and a higher temperature will speed up
the reaction but if the temperature is too high then the reaction will
be slowed down.
Apparatus
Preliminary work
I did a preliminary test in order to help me plan my experiment out
more carefully and so I can get an idea of what's going to happen. I
tested the yeast in temperatures of 20°c and 70°c (the range that I
will be testing in in my final experiment).
Preliminary Results
Temperature tested
Bubbles counted
20°c
15
70°c
2. A test tube was then filled with 35ml of yeast and placed in the
to get an idea of how I would do my real experiment and what apparatus
... more experienced or give some training in a bid to avoid careless mistakes during the experiment.
mean that we will to set up the apparatus in a way that would give us
In ten days you will be able to answer this important question and make a contribution to science!
Human beings are selfish in nature, we think about our needs and wants and how we can advance in society without taking into consideration the well-being of others. Sometimes it takes a little push from an outside source to put things into perspective. In Voltaire's Candide and Jonathan Swift's A Modest Proposal, humans are depicted in this same light, as being greedy and vulgar. The author's intentions are to depict amoral ideas in order to shock readers into questioning their morals. The very fact that the authors believe that their audience can be shocked into moral positions demonstrates their optimistic viewpoints.
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.
As I do this experiment the thing I am going to be changing is the
gives you a clear picture in your mind as to how the area looks. The
5. Pour away as much of the top layer of water as possible to speed
The pH of the solution would alter the rate of the reaction if it was
This lab attempted to find the rate at which Carbon dioxide is produced when five different test solutions: glycine, sucrose, galactose, water, and glucose were separately mixed with a yeast solution to produce fermentation, a process cells undergo. Fermentation is a major way by which a living cell can obtain energy. By measuring the carbon dioxide released by the test solutions, it could be determined which food source allows a living cell to obtain energy. The focus of the research was to determine which test solution would release the Carbon Dioxide by-product the quickest, by the addition of the yeast solution. The best results came from galactose, which produced .170 ml/minute of carbon dioxide. Followed by glucose, this produced .014 ml/minute; finally, sucrose which produced .012ml/minute of Carbon Dioxide. The test solutions water and glycine did not release Carbon Dioxide because they were not a food source for yeast. The results suggest that sugars are very good energy sources for a cell where amino acid, Glycine, is not.
I will now conduct a plan in the forms of a flow chart to show what I
Knowledge is power when discussing the classes you have taken in college and how it affects your everyday life. Microbiology is one of those important classes where although for a majority of majors you do not have to take it and therefore will not learn the information discussed in it, other majors such as biology and nursing require you to take it. They will require you to take it because you will encounter some of the information being taught in it in the work field. As a nurse practitioner I have worked in the field with many patients who were diagnosed with Leprosy, Escherichia coli, Salmonella and other bacterial diseases. All of these diseases that I have encountered in patients were ones I was familiar with due to learning about them as a student in microbiology at CSUB. My children plan on