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Factor that affects the rate of enzyme reaction
Methods of experimentation
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Investigating the Effect of Enzyme Concentration on the Hydrolysis of Starch with Amylase Aim: Investigate the effect of enzyme concentration on the rate of an enzyme-controlled reaction. Using amylase and starch as my example. Introduction: I am investigating the effect of the concentration of the enzyme, amylase on the time taken for the enzyme to fully breakdown the substrate, starch to a sugar solution. The varied variable will be the concentration and all other variables are going to be fixed. The different concentrations will be: 0.5% 0.75% 1.0% 1.5% 2% An enzyme is a class of protein, which acts as a biological catalyst to speed up the rate of reaction with its substrates. Enzymes have the ability to act on a small group of chemically similar substances. Enzymes are very specific, in the sense that each enzyme is limited to interact with only one set of reactants; the reactants are referred to as substrates. Substrates of an enzyme are the chemicals altered by enzyme-catalysed reactions. The extreme specific nature of enzymes are because of the complicated three-dimensional shape, which is due to the particular way the amino acid chain of proteins folds. The three-dimensional contour limits the number of substrates that can possibly react to only those substrates that can specifically fit the enzyme surface. Enzymes have an active site, which is the specific indent caused by the amino acid on the surface that fold inwards. The active site only allows a substrate of the exact unique shape to fit; this is where the substance combines to form an enzyme- substrate complex. Forming an enzyme-substrate complex makes it possible for substrate molecules to combine to form a product. In this experiment, the product is maltose. The 'lock and key' hypothesis explains how enzymes only work with a specific substrate. The hypothesis presents the enzyme as the 'lock, and the specific substrate as 'key'. The active site binds the substrate, forms a product, which is then released. Diagram 1- a diagram showing the 'lock and key' mechanism works
To begin the study, I first calculated how much of each solution I would need. I knew that the final volume of my reaction solution needed to me 30ml, so I calculated how much of starch, amylase, and tris buffer I would need. I used the formula Concentration (initial stock solution) x Volume (initial stock solution)= Concentration (final solution) x Volume (final solution). Using this formula, I found that I would need an initial concentration of 21 ml of starch, 1 ml of amylase, and 8 ml of the tris buffer. After calculating the amounts of substances I would need, I created two different solutions, one with the Carb Cutter and one without. Carb Cutter claims to block starch, however, to find this I needed to test the absorbance level of the control to compare the effect Carb Cutter had on the solution. Below is a graph showing the concentration of the control reaction over one minute intervals through the
This evidence alone suggests that higher increases in substrate concentration causes smaller and smaller increases in enzyme activity. As substrate concentration increases further, some substrate molecules may have to wait for an active site to become empty as they are already occupied with a substrate molecule. So, the rate of the reaction starts to level off resulting in a plateau in the graphs. This means that the reaction is already working at its maximum rate, and will continue working at that rate until all substrates are broken down. The only way the reaction rate would increase, is if more enzyme was added to the solution. This confirms that increases in substrate concentration above the optimum does not lead to greater enzyme activity. Therefore, the rate of reaction is in proportion to the substrate
called an active site. This active site is made by a few of the amino
I will use these tests to see whether I need to change my amounts of
An Investigation into the Effect of Lipase Concentration on the Hydrolysis Of Fats Using the data loggers a recording of the pH was taken every 5 seconds and for each experiment the data loggers produced graphs of the change in pH. From each of these graphs a gradient was calculated which showed the rate of pH change per second. Firstly I calculated the gradients by choosing the steepest section of the graph and dividing the change in pH of this section by the time. However this method proved to be quite inaccurate giving very varied results, for example in these results the average rate of reaction for the 4% lipase solution (-0.457 pH/min) was lower than the 3% lipase solution (-0.471 pH/min). Also the rates in the 2% lipase solution ranged from -0.01 pH/min to -0.95 pH/min showing little reliability in the results. This was partly as I was only guessing which the steepest part of the graph was.
How Amylase Concentration Affects the Rate of the Starch Concentration In this piece of coursework, I have to carry out an investigation to find out how amylase concentration affects the rate of starch. Enzymes are biological catalysts that speed up the chemical reaction that goes on inside living things. An enzyme acts on substrate and may do its job inside or outside the cells. However, the rate at which enzymes work are affected by the following factors/variables: Concentration:
Affect of the Rate of Reaction of Amylase on Starch and How Its Affected by the Concentration of the Substrate
Investigating The Effect of Temperature on the Structure of an Enzyme Introduction: For my GCSE Biology assessment I will be investigating the enzyme amylase with the substrate starch. This reaction, which I am going to investigate, is called the protein test for starch. Aim: My intention for this observation is to examine how the enzyme catalyses are affected by changes in temperature. Safety Precautions: In this investigation I am going to make sure that everything is as safe as possible and prevent any accidents from occurring.
An enzyme can be defined as a protein that acts as a catalyst in a biological system. It increases the rate of reaction by decreasing the activation energy. The catalytic power and specificity of an enzyme can be altered by the binding of certain molecules. These molecules are referred to as inhibitors. An inhibitor works to prevent the formation, or to cause the breakdown of an enzyme-substrate compound. There are two categories of inhibitors. The first being irreversible inhibitors, and the second being reversible inhibitors. Irreversible inhibitors tend to be more tightly bound, covalently or noncovalently (mostly covalently), to the enzyme than reversible inhibitors, which tend to dissociate more rapidly from the enzyme. Reversible inhibitors can be subdivided into three groups: competitive, uncompetitive, and noncompetitive.
Mainly because different enzymes have different pH, and temperatures that they act on with. Adding more substrate can causes the enzyme to increase in activity. In the experiment you have ethanol who worked best with the changes of ph and temperature, whereas methanol was not so successful with the changes. The four alcohols each had the same reaction group but each had different chain length. Ethanol has a 2 chain length, Propanol 3, Methanol 1, and Butanol 4. As you can see in graph 2, the preferred alcohol was ethanol and the least preferred was methanol. You see this because ethanol has the highest absorbance and methanol has the least. The size of the substrate can determine how quickly the enzymes is able to recognize
The enzymes have active sites on their surfaces to allow the binding of a substrate through the help of coenzymes to form enzyme-substrate complex. The chemical reaction thus converts the substrate to a new product then released and the catalytic cycle proceeds.
= == In relative terms enzymes are biological catalysts; control the rate of chemical reaction, different temperatures and pH’s affect their optimum rate of reaction in living organisms. In detail; enzymes are globular proteins, which catalyse chemical reactions in living organisms, they are produced by living cells – each cell has hundreds of enzymes. Cells can never run out of enzymes as they or used up in a reaction.
If I was to do this experiment again I might use a Fungi amylase to
How the Concentration of the Substrate Affects the Reaction in the Catalase Inside Potato Cells Introduction Enzymes are made of proteins and they speed up reactions, this means that they act as catalysts. Hydrogen peroxide is a byproduct of our cell's activities and is very toxic. The enzymes in our bodies break down the hydrogen peroxide at certain temperatures they work best at body temperature, which is approximately 37 degrees. At high temperatures, the cells begin to denature. This means that the hydrogen peroxide is prevented from being broken down because they will not 'fit' into the enzyme.[IMAGE] Objective I am going to find out how the concentration of the substrate, hydrogen peroxide affects the reaction in the catalase inside the potato cells.
I blanked it with 2 cm³ water, 1 cm³ amylase and 3 drops of iodine.