We recently performed a yeast fermentation lab in class to determine the effects of different sugars (sucrose, lactose and dextrose) on the rate of fermentation. I am writing up my lab report, however I am having some difficulties. If sucrose and lactose have the same molecular formula, what makes them different? The results in my lab from the two sugars are COMPLETELY different, why could this be? Also, different groups of students did different sugars: the sucrose and lactose groups measured the amount of CO2 every 2 minutes, but the dextrose group measured every 4 minutes, so how do I properly record all the data and find the averages without anything being messed up? Thank you!
The differences in chemical properties of the two molecules, with the same formula, are due to the different ways the atoms are arranged in the molecule.
As for recording the data, plot both results on a CO2 vs time scale, with the same coordinate scales. The dextrose data will have half as many points but that will not matter much when fitting a curve to the data. I do not know what kind of averages you will be calculating. Measurements made by different groups?
To understand why sucrose and lactose yield different results in the fermentation lab, it's important to first understand their chemical structures and how they are broken down by yeast.
Sucrose and lactose both belong to a group of carbohydrates known as disaccharides, which means they are composed of two sugar molecules linked together.
Sucrose, commonly known as table sugar, consists of one glucose molecule and one fructose molecule linked together. On the other hand, lactose, found in milk, is made up of one glucose molecule and one galactose molecule linked together.
When yeast performs fermentation, it breaks down the disaccharides into their individual sugar components and converts them into ethanol (alcohol) and carbon dioxide (CO2) as byproducts. This process is facilitated by specific enzymes produced by the yeast.
Now, coming to the differences in the lab results, there are a few factors that could contribute to different outcomes between the sucrose and lactose groups:
1. Enzymatic availability: Yeast may produce different amounts of enzymes to break down sucrose and lactose. If the yeast produces more enzymes specific to sucrose, fermentation of sucrose will be more efficient compared to lactose.
2. Efficiency of sugar breakdown: Even if the yeast produces a similar amount of enzymes for both sucrose and lactose, the efficiency of breaking down and utilizing each sugar may be different. This difference in efficiency could result from variations in the enzyme-substrate affinity or the metabolic pathways involved.
3. Intrinsic characteristics: Sucrose and lactose have different molecular structures, which can affect their solubility and accessibility to yeast enzymes. This variation could impact the rate of sugar breakdown and consequently influence the fermentation rate.
Regarding the data recording and calculating averages, you need to consider the difference in time intervals between the two groups. Since the sucrose and lactose groups measured CO2 production every 2 minutes, and the dextrose group measured every 4 minutes, you cannot directly compare the absolute CO2 values across the groups.
To properly record and analyze the data, you can calculate the average CO2 production rate for each group. This can be done by dividing the change in CO2 (measured at two different time points) by the time interval between those measurements. By calculating the average CO2 production rate, you can then compare the relative rates of fermentation among the different sugar groups.
Additionally, it would be helpful to plot the CO2 production over time for each group separately. This will provide a visual representation of the fermentation rate and allow for a more accurate interpretation of the results.
Remember to clearly explain these considerations in your lab report to demonstrate your understanding of the factors that could influence the fermentation rate and the appropriate data analysis methods used.