Cellular Respiration

During this experiment, sugar sources were varied and respiration rate evaluated. To begin, a water bath was set at 30 degrees Celsius. This creates an optimum temperature for the enzymes in yeast to breakdown sugar and give off CO₂. Each sugar source, glucose, sucrose, lactose and glycerol were all added to its own unique yeast sample, one at a time. Each sugar source that was added to the yeast solution was immediately incubated for 10 min, then was transferred to a respiration chamber. The CO₂ sensor was put in, recording the CO₂ respiration for 4 min. This process was done for each sugar source. The reparation rate was recorded through Logger Pro. After 4 min passed, the slope was recorded, resulting in respiration rate.

Yeast is a fungus that can generate glucose into energy without using any oxygen molecules. We tested the fermenting ability of yeast from two different carbon sources: glucose and aspartame. We hypothesized that yeast is unable to use the carbon sources of aspartame. To do this, we decided to use both carbon sources in the same concentration. Each carbon source was mixed with the same amount of yeast solution. The experiment group of 5.5 mM aspartame solution was compared with the control group of 5.5mM glucose solution. We recorded the rate of fermentation for glucose and aspartame in the Vernier Lab Quest. The fermentation rate of aspartame is a negative number, and glucose is a positive number. Our results show that yeast was unable to ferment aspartame as yeast fermented glucose. The results indicate that aspartame has no effect on yeast fermentation rate because yeast do not catabolize aspartame because it does not have the appropriate enzymes to break it down.

In this lab we tried to find what fuels yeast could metabolize and what the yields of the carbon dioxide gas that were produced from the different sugars used. We used 6 different yeast and sugar mixtures. The different yeast and sugar mixtures we used were control, glucose, sucrose, fructose, starch, and saccharin. The results for the 6 different results are presented in Tables 1-6 and Graph 1. Graph 1 is a graph of all the information in Tables 1-6. Each Table and graph is labeled approximately.

After performing with carbohydrates, we performed same steps by adding different pollutants. The amount of CO2 produced in this case is less.

The sugar begin to ferment in the process of glycolysis and 　　　the carbon dioxide gas is one common co-product fermentation. Only fructose, mannose and glucose produced CO2 in this experiment. They have reaction to be ferment and produce CO2 after obtaining phosphate. It means that the yeast must have a phosphoric acid in it. They also pointed out that the galactose must be converted a form of glucose to gain a phosphate by through the process of three steps.

The purpose of this experiment is to determine the rate of fermentation in yeast cells as they are converted to alcohol with the use of five different sugars (Sucrose, Glucose, Equal®, Splenda®, and Brown Sugar (sucrose with molasses)). Yeast uses sugar to make chemical energy, as a result alcohol and carbon dioxide are also formed as a byproduct. Generally, fermentation is an anaerobic process and a means of creating ATP without the presence of oxygen. During fermentation, the sugar(s) will be transformed into two 3-Carbon sugars known as pyruvate, from there, the pyruvate is turned to ethanol alcohol (Holcberg, 1981). The experimental organisms in this lab are the brown sugar and sugar substitutes Equal® and Splenda®, they are being compared

The hypothesis stats that as the sucrose concentration is increased, rate of respiration will increase and therefore the CO2 production of yeast cells will rise. Sucrose is a disaccharide composed of the monosaccharaides glucose and fructose. Glucose is a reactant in anaerobic cell respiration. In the absence of oxygen, glucose will react with the yeast producing ethanol and CO2.

Sugars are vital to all living organisms. The eukaryotic fungi, yeast, have the ability to use some, but not all sugars as a food source by metabolizing sugar in two ways, aerobically, with the aid of oxygen, or anaerobically, without oxygen. The decomposition reaction that takes place when yeast breaks down the hydrocarbon molecules is called cell respiration. As the aerobic respiration breaks down glucose to form viable ATP, oxygen gas is consumed and carbon dioxide is produced. This lab focuses on studying the rate of cellular respiration of saccharomyces cerevisiae, baker’s yeast, in an aerobic environment with glucose, sucrose, lactose, artificial sweetener, and water as a negative control. A CO2

This is because in addition to DPIP and mitochondrial suspension, succinate was also mixed. By adding succinate the DPIP was reduced thus allowing cellular respiration to continue. The DPIP prevents the hydrogen ions released from succinate converting it from oxidized to reduced. Furthermore, this changes the color of the sample from blue to clear. When the succinate was added, there was an upsurge in percent transmittance.

Hypothesis: The yeast will have a greater rate of respiration for the natural sugars specifically the glucose and lower rate of respiration for the unnatural sugars

To begin the experiment, six fermentation flasks were acquired. Six milliliters of 10% glucose was pipetted into each flask, followed by 10 mL of deionized water and 8 mL of the prepared yeast solution. After each flask was placed at the appropriate temperatures necessary for the experiment, the production of CO2 started to be monitored. Data was recorded consecutively every two minutes over a time period of twenty minutes, and recorded in a data chart.

Similarly, maltose and cellulose are fermented by yeast through respiration of the yeast cells. The process of fermentation is beneficial because it produces enzymes that are good for the human body, Vitamin B, fatty acids such as Omega-3 and probiotics. Fermentation also helps with digestion because it breaks down foods into a more digestible form (Wellness Mama). Previous experiments conducted with yeast cells have revealed that the rate of fermentation is affected by substrate concentration and enzyme concentration. However, this experiment will investigate the effects of two different disaccharides and one polysaccharide on fermentation, while maintaining constant substrate and enzyme concentrations.

The purpose of this investigation is to test the effect of different sugar sources on yeast respiration.

The rate of fermentation in this investigation was represented by the amount of carbon dioxide produced as a byproduct of fermentation in the given time.

As the diagram on the right displays, one molecule of Glucose produces two molecules of carbon dioxide and two molecules of ethanol. The fermentation of glucose to ethanol is only possible if oxygen is absent otherwise instead of producing ethanol and carbon dioxide, lactic acid is produced instead.