Affect of Sugars on Yeast Respiration
RaeAnne Smith
HL Biology Y2
Soule: Period 7
10 October 2011
Affect of Sugars on Yeast Respiration
Introduction
Cellular respiration can be defined as the release of energy, or the breakdown of carbohydrates into carbon dioxide and water1. Cell respiration takes place in the mitochondria of animals and in the cytoplasm of plants. The formula for aerobic cellular respiration is: c6H12O6+ 6O2→6CO2+6H2O
Aerobic respiration occurs when oxygen is present, while anaerobic respiration occurs when there is no oxygen present. In anaerobic respiration, ethanol and carbon dioxide are produced.
In this investigation, the rate of carbon dioxide production (cellular respiration) of yeast using different sugars and one artificial sugar will be measured. The natural sugars used in this investigation will be sucrose (table sugar) and lactose (in milk). The artificial sugar that will be used is aspartame (equal). The rate of respiration between the natural sugars will be compared to that of the artificial sugar. The molarity of the sugar will remain constant at 0.4M for all the sugars used and the amount and type of yeast used will be the same. It is expected that the yeast will have a higher rate of respiration for the natural sugars than the artificial sugar. As aspartame is about 200 times sweeter than natural sugar, only small amounts are put into packets of equal, and other substances such as dextrose or maltodextrin are used as "fillers" to make it appear as though there is more aspartame in the packet than there is2. It is predicted that because there is only a very small amount of sugar in the equal packets, that the yeast will have less to metabolize, and therefore the rate of respiration will be lower.
Design
Research Question: How do natural sugars versus artificial sugars affect the rate of cellular respiration in yeast?
Dependent Variable: The sweetener used - sugar (sucrose and lactose) vs. artificial sugar (aspartame).
Independent Variable: The
HL Biology Y2
Soule: Period 7
10 October 2011
Affect of Sugars on Yeast Respiration
Introduction
Cellular respiration can be defined as the release of energy, or the breakdown of carbohydrates into carbon dioxide and water1. Cell respiration takes place in the mitochondria of animals and in the cytoplasm of plants. The formula for aerobic cellular respiration is: c6H12O6+ 6O2→6CO2+6H2O
Aerobic respiration occurs when oxygen is present, while anaerobic respiration occurs when there is no oxygen present. In anaerobic respiration, ethanol and carbon dioxide are produced.
In this investigation, the rate of carbon dioxide production (cellular respiration) of yeast using different sugars and one artificial sugar will be measured. The natural sugars used in this investigation will be sucrose (table sugar) and lactose (in milk). The artificial sugar that will be used is aspartame (equal). The rate of respiration between the natural sugars will be compared to that of the artificial sugar. The molarity of the sugar will remain constant at 0.4M for all the sugars used and the amount and type of yeast used will be the same. It is expected that the yeast will have a higher rate of respiration for the natural sugars than the artificial sugar. As aspartame is about 200 times sweeter than natural sugar, only small amounts are put into packets of equal, and other substances such as dextrose or maltodextrin are used as "fillers" to make it appear as though there is more aspartame in the packet than there is2. It is predicted that because there is only a very small amount of sugar in the equal packets, that the yeast will have less to metabolize, and therefore the rate of respiration will be lower.
Design
Research Question: How do natural sugars versus artificial sugars affect the rate of cellular respiration in yeast?
Dependent Variable: The sweetener used - sugar (sucrose and lactose) vs. artificial sugar (aspartame).
Independent Variable: The