Variables Case
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Variables-
Controlled; a controlled lab environment (constant temperature, pressure, pH and all other physical properties), 1cm3 of benedicts solution and sucrase was used.
Manipulated; the sucrose concentration in g/dm3 was changed after every reaction, the colour of the benedicts solution.
Responding; the time taken for the formation of the cloudiness, the colour change of the benedicts solution.
Sucrase is the name given to a number of enzymes that catalyze the hydrolysis of sucrose to fructose and glucose. Sucrose itself is a non-reducing sugar and therefore will not test positive with Benedicts solution. In order to test for sucrose, the sample is treated with sucrase. The sucrose is hydrolysed into glucose and fructose, with glucose being a reducing sugar, which in turn tests positive with Benedicts solution.
Reason for temperature at 40 and not above:
Temperature
Increasing temperature increases the Kinetic Energy that molecules possess. In a fluid, this means that there are more random collisions between molecules.
Since enzymes catalyse reactions be randomly colliding with Substrate molecules, increasing temperature increases the rate of reaction, forming more product.
However, increasing temperature also increases the Vibrational Energy that molecules have, specifically in this case enzyme molecules, which puts strain on the bonds that hold them together.
As temperature increases, more bonds, especially the weaker Hydrogen and Ionic bonds, will break as a result of this strain. Breaking bonds within the enzyme will cause the Active Site to change shape.
This change in shape means that the Active Site is less Complementary to the shape of the Substrate, so that it is less likely to catalyse the reaction. Eventually, the enzyme will become Denatured and will no longer function.
As temperature increases, more enzymes molecules Active Sites shapes will be less Complementary to the shape of their Substrate, and more enzymes will be Denatured. This will decrease the rate of reaction.
In summary, as temperature increases, initially the rate of reaction will increase, because of increased Kinetic Energy. However, the effect of bond breaking will become greater and greater, and the rate of reaction will begin to decrease.
The temperature at which the maximum rate of reaction occurs is called the enzymes Optimum Temperature. This is different for different enzymes. Most enzymes in the human body have an Optimum Temperature of around 37.0 oC.
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ABSTRACT
Enzymes react differently under different conditions and concentrations, being the most productive at the enzymes specific optimum condition and concentration. The enzyme sucrase, extracted from yeast, breaks down the complex sugar sucrose into the simple sugar glucose. Testing for sucrases optimum environment, multiple reactions were ran using varying amounts and concentrations of sucrose and sucrase at different pHs and temperatures. The product was then treated with Benedicts solution to visually observe what amount of glucose was present after the reaction was ran; negative results being little to no glucose present and positive results being glucose present. The varying levels of colors created by the Benedicts test were recorded as 1 (negative) blue; 2 green; 3 yellow; 4 (positive) orange; and 5 (positive) red. After running the reactions to determine the optimum temperature and pH, 37 degrees Celsius was determined to be the optimum temperature while pH 2.0 was determined to be the optimum pH. This means that under these conditions the enzyme will help produce the most product from the substrate. After finding the optimum conditions the two different concentrations of sucrose were ran for ten minuets taking an initial sample and then subsequent samples every minuet, under those conditions, one concentration at 2.5% sucrose and again at 10% sucrose. The 10% sucrose had the most positive results because there were sufficient active sites to bind with most of the sucrose present producing glucose more efficiently than the 2.5% sucrose. As with the 2.5% sucrose all of the sucrose was bond to the active sites of sucrase and there were still more active sites available. The 2.5% sucrose did not take advantage of all the active site available because not enough substrate was present therefore creating less glucose in the ten-minuet time trial. Therefore the optimum temperature for sucrase is 37 degrees Celsius, the optimum pH is 2.0, and the optimum concentration is 10%.
INTRODUCTION
Enzymes analysis enables scientist to look the what, why, and how of life. A majority of reactions inside to human body are endothermic, without enzymes lowering the activation energy of these reactions life would not be possible. By understanding what the optimum environments of enzymes are, specifically with sucrase, scientist can better understand enzyme kinetics. In the body thousands of enzymes help regulate and produce chemicals. One very important enzyme K-ATPase in the body help catalyze the reaction of ATP into ADP creating a free phosphate group and helping create an sodium and potassium electrochemical gradient in the body (Peluffo et al. 2004). If the body did not keep its temperature, pH, and concentration of substrate at the optimum levels enzymes would not be able to process required energy fully and the cells would start to die. Sucrose is an important aspect of life and its reduction to glucose has to be carefully controlled in photosynthesis. In the photosystem 2 stage of photosynthesis sucrose helps stabilize water so hydrogens electrons can be taken and used to create energy (Barry and Halverson et al.2003). As the optimum environment for an enzyme is reached the need to accurately and analytically predict the rate of production through the enzyme arises, such as accurately measuring the activity of RNA polymerase, which transcribes varying DNA sequences (Shaevitz and Block et al.2005). Accurately measuring the enzyme activity of RNA polymerase will enable the ability to accurately measure growth of cells. All of these processes help scientist understand where and how enzymes interact with molecules.
In the analysis of production of glucose from sucrose catalyzed by sucrase the optimum temperature will be slightly above room temperature because the sucrase is derived from yeast which lives in an optimum environment slightly above room