Wednesday, November 27, 2019

Enzyme Experiment with Temperature Essay Example

Enzyme Experiment with Temperature Essay Example Enzyme Experiment with Temperature Paper Enzyme Experiment with Temperature Paper Enzymes are catalysts in the body that speed up the breakdown of food, and are essential in the digestive system. Although food can be broken down by molecules colliding with it, the process is speeded up greatly by enzymes, a type of catalyst. We know from previous knowledge that enzymes are proteins, and they require the presence of other compounds, or co factors, before their catalytic ability can be exerted. Enzymes can be used more that once and are replaced only after a period of time when they are denatured. They are all specific to certain foods, but some are more specific than others. The lock and key theory of enzymes is that each enzyme has a specific key shape, which will only fit into one sort of lock, or substrate. This is illustrated in the below diagram. We also know they are denatured by high temperatures, certain salts, solvents and other reagents, where they lose their lock and key shape, making them useless. Enzymes work by attaching themselves to a bond in the substance and breaking the bond between them. It is because of these reasons we chose to examine enzymes in this experiment. The enzyme we are using is trypsin, which breaks down amino acids in the body. Hypothesis I hypothesise that as the temperature is increased, the rate of reaction will increase. However, when higher temperatures are reached, enzyme reaction rate will drop rapidly as the enzymes are denatured. I have drawn out a hypothesis graph, which I believe will be what the final graph will look like approximately. I have also labelled a number of stages, and explained what will happen to them, as known from past experience and research. We know that even without enzymes in the solution, the rate of reaction would still increase, due to the kinetic theory. The higher the temperature, the more heat energy. Heat energy is converted into kinetic energy, making the water molecules move around more quickly, hence colliding more often with the substrate, helping break it down. We also know that if enzymes are present, when the temperature is higher, the substrate will move more quickly into the active site. At stage 1 on the graph, the rate of reaction increases at a similar rate to the temperature, that is, the increase is roughly proportional. At stage 2, the enzyme activity is at its peak, I believe around 40 degrees. At stage 3, the enzyme is becoming denatured from the high temperatures, and is losing its unique shape, which allows it to catalyse substances. At stage 4, the high temperatures have completely denatured the enzyme, making it ineffective as a catalyst. 20o Variables There are a number of different types of variable in this experiment. The independent variable in this test is the temperature. We ensured that this stayed exactly as we wanted it by checking the temperature before inserting the photographic film. This is the only variable we should be changing and have direct control of. The dependant variable is the result we want, that is, the rate of reaction. If we perform the experiment correctly, the only thing that should be affecting the dependant variable is the independent variable, the temperature. All other variables, such as pH and the size of the photographic film, should be kept constant to ensure a fair test. If we change the pH, the enzymes bonding will change and cause it to lose its active site. This would make the test unfair, so we added buffer to the solution to keep the pH constant. If the photographic film size was not constant, it would take longer for the enzymes to break down the gelatine on some of the film, while the experiments with smaller pieces of photographic film would be broken down faster. To ensure all conditions are identical apart from temperature in each test, we kept the size of the photographic film to exactly 4mm squared. We also ensured that all tubes were given 10 minutes to acclimatise to the appropriate temperature. This is discussed later in detail. The temperature, the main variable we will be controlling, we have decided to test the trypsin at 0 degrees, 20 degrees, 40 degrees, 60 degrees and 80 degrees. We decided to choose this range, as it should provide a large spectrum of results, and are at the same time not too far apart in temperature, so we can hypothesise what results between them will be once we have our set of results. We made the temperatures precise by using water baths set to exactly the correct temperature, or an icebox at exactly 0 degrees. We also used a thermometer to ensure the temperatures were correct just before starting the experiment. Before beginning, we ensured the area was safe by wearing safety goggles and clearing the nearby area of books or obstacles. We placed 10 test tubes in the test tube rack. 5 were control tubes, so we added exactly 3ml of water to each of the 5. We then added 3ml of trypsin solution to the other 5. We inserted the photographic film squares, of 2mm squared in size, into each of the 10 splints. There were two tubes, one control and one test, at each temperature. We placed two test tubes, one filled with water, the other filled with trypsin, in the icebox. We placed two in a rack to stay at room temperature. Two were placed in the 40-degree water bath, two in 60 degree water bath, and two in the 80-degree water bath. Each one was allowed to acclimatise to the appropriate temperature in its water bath/environment for 10 minutes. This also ensured that the trypsin would denature if it were at too high a temperature, discussed in detail later. Stopwatches were started at the point when the splints were placed into the tube. Every 10 seconds the film would be examined. The timer was stopped only when the film was clear, so that all the film had to reach the same stage (eliminating the possibility of human error as to judging when the enzyme has completed its job). We then recorded all our results in a table, as shown below the Fair Test Section. Finally, we all washed our hands to ensure any trypsin on them was washed off. Fair Test Ensuring that the experiment was a fair test was one of the most important parts of the experiment; if each test were not fair, then the results would be incorrect. The first thing we had to be sure of was that we did not contaminate the trypsin with dirt or bacteria that may have been on our fingers, as this may have affected the rate at which the enzyme works. We also made sure that all the test tubes reached their correct temperature and were allowed to acclimatise for 10 minutes. This is important for two reasons, the first being that if we did not ensure the test tube was at the correct temperature, then the results would not be a correct reflection of what we had hoped to achieve. Also, it is important to remember that at high temperatures, enzymes work at accelerated speeds for short periods of time before denaturing (when the enzymes lose their key shape so they cannot fit in the lock of the substrate), whereby they are useless. We can see this in commercial industry, where enzymes are used at extremely high temperatures when they work very quickly, and then denature and are removed for another batch of enzymes to work. It is also important we keep pH constant, as if the pH changes, the bonding of the enzyme would change, causing it to lose its active site. This could affect the results and therefore our final conclusion, so we used buffer to regulate the pH. We also decided to keep the photographic film size at exactly 2mm squared. If photographic film were at different sizes, then in some test tubes the trypsin would have to work for longer to break down the larger piece of photographic film, hence increasing the result time and making the test unfair. To ensure complete accuracy, we checked our stopwatch every ten seconds instead of twenty or longer, so that we could pinpoint exactly when the photographic film had become transparent.

Saturday, November 23, 2019

Essay on Spicing up Of Mice and Men

Essay on Spicing up Of Mice and Men Essay on Spicing up Of Mice and Men Spicing up of Mice and Men In of Mice and Men, John Steinbeck uses many figurative language to engage the readers in the story. Of Mice and Men is a story about two migrant workers, trying to find a job. The main characters in the story are George and Lennie. George who is the â€Å"small and quick and dark of face† ; Lennie on the other hand is a man of tremendous size and has the mind of a young child. With hope and dreams, these two men cling onto each other to achieve them. To give the story a more interesting flow, Steinbeck uses many figurative languages. Steinbeck uses simile, personification, and metaphor to appeal to the emotions of the readers. Similes in the story was used to engaged and invoke emotions in the reader. An example , â€Å"snorting into the water like a horse† (Steinbeck 3). In this simile the author is saying that the way Lennie drinks is similar to how a horse drinks. Lennie and a horse are similar in the way their mind works: if its thirsty i t drinks, if its hungry it eats, if its tired it sleeps. They do this without any real thought about what's going to happen when they become hungry or thirsty. This simile makes the reader imagine Lennie as an actual horse. Another example is , â€Å"Her hair hung in little rolled clusters, like sausages† (Steinbeck 31). the authors is saying the in this simile its comparing Curley’s wife's hair to sausages. Also the simile is effective because Steinbeck is comparing her to meat, which is symbolic for the way she is treated by the others, as a piece of property or meat. The simile makes readers imagine little rolled sausages on her head. Along with simile, Steinbeck uses another type of figurative language which is personification. The use of personification in the story grabs the readers attention , making them more involved. For example, â€Å"The shade climbs up the hills towards the top.† (Steinbeck 2) This is an example of personification because shade ca nnot literally climb up a hill. Steinbeck is trying to portray a more human quality in the shade. Its making the readers imagine the shades having legs like human , climbing up towards the hills. Another example, â€Å"A little shed that leaned off the wall of the barn† (Steinbeck 65) Steinbeck described where the shed is located in comparison to the barn. He could’ve said the shed was next to the barn but instead he defined the shed as being lazy in its posture just leaning on the barn. This personification forms a

Thursday, November 21, 2019

Food Journal Reflections Lab Report Example | Topics and Well Written Essays - 250 words

Food Journal Reflections - Lab Report Example I had one and a half serving of vegetables and one serving of fruit per day (organic content) which I considered too little. For foods with animal products, I took a glass of milk for each of the two days. Most of the foods I ate are local foods. Most of the foods stocked in the grocery and supermarket stalls in the country are local foods. It is important to prompt the local food industry by consuming more of the local foods than the imported ones (Wang,2014). The local foods are of an immense variety each containing specific nutritional requirements.The average American eats one serving of fruit and vegetable each day which is too little to provide the necessary organic requirements. There is also an increasing amount of meats consumption in American households while foods containing other essential animal products like minerals are on the decline. A healthy diet requires that an individual eats a balanced diet every day while striving to sustain a caloric intake of about 2000 calories per day. This requires cutting down on meat consumption to at least once per two days and increase the intake of foods with organic content like fruits and vegetables to at least once per day. Along with fruits and vegetables, individuals should also strive to have at least every meal providing essential animal products apart from meat (Wang, 2014). Such products include milk, eggs et cetera. Wang, D. D., Leung, C. W., Li, Y., Ding, E. L., Chiuve, S. E., Hu, F. B., & Willett, W. C. (2014). Trends in dietary quality among adults in the United States, 1999 through 2010.  JAMA internal medicine,  174(10),