Biology Lab Report
Investigating Alcoholic Fermentation and the Affects of Yeast on Dough
Aim: The aim was simply to investigate whether or not yeast had any affect on causing dough to rise when baked and to experiment with alcoholic fermentation eg. to see if it gave off carbon dioxide.
Introduction: Following a few weeks of fermentation theory, groups of three to four were assigned and told to conduct a series of experiments involving the affects of fermentation. My group consisted of myself, Won Jin, Brendan and Sun-Ho and we chose to investigate alcoholic fermentation and the affects of yeast on dough, more specifically to see if yeast caused the dough to rise in anyway. We followed the instructions in our biology textbook on page 129.
Hypothesis: According to what I’ve learned, I would expect that the yeast does indeed cause the dough to rise due to the carbon dioxide gas given off by the yeast. For our alcoholic investigation, I can safely assume that carbon dioxide will be given off as the formula for anaerobically respiration in alcoholic fermentation for turning glucose into alcohol is [ Glucose -> Alcohol + Carbon Dioxide + Energy ] so obviously Carbon Dioxide is a part of this. Also I assume that the fermentation will give off heat and the sugar will probably be turned into alcohol.
Materials: ca. 100 g flour
Water
Yeast
10 per cent solution Glucose
Liquid Paraffin
Four Test Tubes
Lime Water (Used as an indicator)
Practical: Our first experiment was to see if yeast impacted dough in anyway and to do this we brought in supplies such as flour and yeast. We followed the instructions and made three groups of dough. For each group we added 50 g of flour and added a little bit of water while mixing it. Due to my lack of “kitchen skills” I had to throw away my first two attempts, as they had gotten too sticky. But like they say, third time’s the charm and we finally made suitable dough.
We mixed warm water and yeast together in a bowl and added about 10 g of sugar, which is necessary for the dough to expand. We split the dough into two smaller mounds and added the yeast solution with only one of them to see the difference of dough with yeast and dough without yeast subjected to the same conditions to analyse the difference.
We placed both mounds of dough on top of a windowsill where we would leave it for an hour.
2. A test tube was then filled with 35ml of yeast and placed in the
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Cosmetic Surgery is the procedure done to restore or improve one’s physical appearance. The use of surgery to have an actualization of a want tends to be unneeded since it is not in line with the purpose of reestablishing what was lost or damaged. Although cosmetic surgery intends to be used for restoration purposes, many people have abused it for the sake of vanity. Cosmetic surgery also has good and bad effects on the person in many different aspects.
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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.
Culture plates of yeasts strains: S41, a pet 1 and M240, conical flasks containing Yeast Extract Potassium Acetate (YEPA), Yeast Extract Peptone Dextrose (YEPD) and Yeast Extract Palm Olein (YEPPO) media, pH indicator, inoculation loop, microscope, methylene blue, Bunsen burner and incubator.
Cosmetic Surgery has been around ever since the early wars to repair scars and injuries but, “today, cosmetic plastic surgeries outnumber reconstructive ones in many countries.” (Edmonds, 2012, p. 134). Cosmetic surgery continues to grow in popularity all around the world. It has now evolved to beautify an unattractive physical appearance. In 2013, Americans spent more than seven billion dollars on cosmetic surgery according to a website titled, Healthline. Cosmetic surgery may sound ideal to someone who is unhappy with a physical appearance but it can be very dangerous. According to “The Culture of Beauty”, “analysts agree that because
Experimental Strategy: In this experiment, the yeast being used is called Saccharomyces cerevisiae. This type of yeast follows fermentation which is very unique and can tell how much carbon dioxide is produced by fermentation more accurately compared to cellular respiration. Three test tubes will be filled with a specific volume and concentration of sugar with a certain amount of yeast in each test tube. Two of the three test tubes will have similar concentrations of sugar with different amounts of yeast...
Cosmetic surgery consists not just of enhancing someones beauty, but also to help those who have been badly damaged in an accident or who have physical birth defects. Many believe that women are the main gender that go for cosmetic surgery. Yet studies have shown that 11% of men are also getting cosmetic surgery - in fact since 1992, the percentage of men getting cosmetic surgery has gone up by 50%. Middle aged men see plastic surgery as an investment in their career prospects. It is important to know that it is neither sex nor age which makes some type of aesthetic surgery procedure feasible, but what is important is a good general health condition.