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
Fermentation is the biological process which allows humans to brew beer, or any other alcoholic beverage. This process occurs in the absence of oxygen, as a means for the cell to produce adenosine triphosphate (ATP), the source of cellular energy. Though little energy can be produced in this manner, it allows the yeast to survive in t...
· Add 2g of yeast to the water and add sugar (1g, 2g, …up to 5g).
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.
The United States Government should deem desecration of the American Flag unconstitutional because of the freedom in which the flag represents, along with the blood, sweat, and tears that were shed by our brave soldiers and veterans. Desecration of the American Flag suggests a disdain, or a disregard for the symbolic meaning under which it represents. The American Flag has forever and a day been an image declaring freedom and democracy, and has showcased our principles and beliefs as a country.
Flag Burning can be and usually is a very controversial issue. Many people are offended by the thought of destroying this country's symbol of liberty and freedom. During a political protest during the 1984 Republican Convention, Gregory Lee Johnson was arrested for burning an American flag. Years later in 1989, Johnson got the decision overturned by the United States Supreme Court. In the same year, the state of Texas passed the Flag Protection Act, which prohibited any form of desecration against the American flag. This act provoked many people to protest and burn flags anyway. Two protestors, Shawn Eichman and Mark Haggerty were charged with violating the law and arrested. Both Eichman and Haggerty appealed the decision because the law was inconsistent with the first amendment to the Constitution. The right to petition the government for a redress of grievances is protected by the first amendment of the Constitution. Burning American flags and other such actions are not treasonous and should no be treated as so, as long as these actions are done to petition the government for a redress of grievances.
Flag defilement is seen in many forms, such as- spitting on, tearing apart, or burning. During the 1960’s, a time of despair and revolution, flag vandalism proliferated. In effort to alter their lifestyle, Americans stampeded the streets ruining the symbol of freedom in the name of politics and racism. The violent array of insubordination created an immediate reaction. Each protest became more violent and ill mannered. Each time someone demolishes a flag, the act is not freedom of speech- it is an expression of an anti-American lifestyle.
Brewers call the addition of yeast pitching. Once the yeast has been pitched the wort can properly be called beer. Fermentation can last a few days or a few weeks depending of the strain of yeast and the strength of the beer. During the process the yeast reproduce and then metabolize the sugars, making C02, alcohol, and a host of other flavorful and aromatic compounds that add complexity to the beer. During the height of fermentation the beer is capped by a thick creamy foam called kreusen. Once the available sugars have been consumed the yeast cells clump together or floc and fall to the bottom of the
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.
Certain states in America still impose the death penalty for serious offences, with the support of the community as it prevents reoffending and aims to prevent future offending (Durlauf, Fu, and Navarro 2013). Data collected over a period of time by numerous studies have conflicting evidence on the success of the deterrent effect. Some suggest that states which enforce the death penalty have lower rates of serious crimes (Radelet and Lacock 2009; Death Penalty Information Centre 2016; Abrams 2012) when compared to states that do not enforce the penalty. While other studies suggest that the rate of serious crimes is lower in states that do not enforce the penalty (Radelet and Lacock 2009, 502; Durlauf, Fu, and Navarro 2013).
Most of us don't like some aspect of our appearance, whether it's sagging eyes or excess weight in particular areas, to name a few complaints. Lately a record numbers of Americans are doing something about it by having plastic surgery. Since 1995, the number of cosmetic procedures, which range from liposuction to facelifts, has almost tripled (English 23). Is that a healthy choice-or a dangerous trend? Aging has become the field of the future for plastic surgeons whose patients have reasons not always valid in the search for youth and beauty.
Louis Pasteur made many advanced and beneficial discoveries. One of these was the discovery that yeast is a living organism, and is the cause of fermentation. From this, he came up with the method of heating wine and beer to prevent it from spoiling (“Louis Pasteur”). Prior to his discovery, wine frequently fermented, which was problematic in the wine industry. Pasteur describes beer’s spoilage: “The beer acquires a sour taste and smell that render it detestable. We have met with this ferment existing in beer, unaccompanied by other ferments and have been convinced of its fatal effects (Pasteur, 19).” Pasteur solved...
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.
The process of alcoholic fermentation begins with the use of enzymes. The enzymes begin to break down the long chains in starch molecules, a polysaccharide that consists of a large quantity of glucose molecules (C6H12O6) joined by glycosidic bonds as seen in figure 1, into single glucose molecules, a monosaccharide with six carbons and five hydroxyl groups. After the starch has become sugar, the enzymes are used once again, this time to convert the sugars into ethyl alcohol and carbon dioxide, CO2, as seen in figure 2 (World of Scientific Discovery, 2007). The carbon dioxide produced is released into the atmosphere, leaving water and ethanol, the alcohol, behind. Ethanol is a colorless flammable liquid with a molecular formula of C2H6O, giving it a molar mass of 46.07 grams per mole. Ethanol is also characterized by a melting point of -114°C or 159 K.
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.