Abstract:
In my experiment I aimed to observe how ranging pH levels will affect the rate in which amylase will break down the starch molecules. I will be measuring the time it takes for the dark liquid to disappear and leave a yellow brown liquid to be shown, which would show that there is no starch present in the solution because it would have broken into maltose by adding amylase. Results did not fully demonstrate what we expected in our hypothesis, but did portray the pattern we expected, with the rate of reaction being highest nearer the middle of the pH scale.
Enzymes are specific-type proteins that act as a catalyst by lowering the activation energy of a reaction. Each enzyme binds closely to the substrate; this greatly increases the reaction rate of the bounded substrate. Amylase enzyme, just like any other enzyme, has an optimum PH and temperature range in which it is most active, and in which the substrate binds most easily.
Introduction
Amylase is an enzyme that catalyzes the breakdown of starch to sugar. They are found in almost in almost all plants, animals and microorganisms. It is difficult to measure the reaction of amylase on starch as there is no clear reaction seeing as the substrate (starch) and the product (maltose) are colourless. This is why iodine must be used as starch appears as blue-black in its presence.
Method
Equipment used:
-Five boiling tube racks -Stopwatch
-Test-tube rack -30cm3 of 1% starch solution
-Three 5cm3 syringes -10cm3 of 1% amylase solution
-dropping pipette -5cm3 of 0.05 mol dm-3 sodium carbonate solution
-white tile -10cm3 of 0.1 mol dm-3 ethanoic acid
-pH indicator paper -iodine solution
-Eye protection
Firstly I labelled the 5 boiling tubes (from 1-5) and then placed 5cm3 of 1% starch solution into each of the tubes. Then with a new syringe I added 1cm3 of 0.05 mol dm-3 sodium carbonate solution to tube 1. Then I added 0.5cm3 of 0.05 mol dm-3 sodium carbonate solution to tube 2. With a new syringe I placed 2cm3 of 0.1 mol dm-3 ethanoic acid to tube 4 and 4cm3 of 0.1mol dm-3 ethanoic acid to tube 5.
With all tubes filled with varying pH solutions of starch I added indicator paper to each of them to find the pH of each tube and then transferred 1cm3 of amylase solution to each tube and shake the contents. Now the solutions are ready, start a stopwatch. I decided to remove a drop with a dropping pipette every two minutes from each tube and placed them on a clean white tile. After adding a drop of each iodine solution to test how much starch had broken down (what the colour of the solution was) I rinsed the pipette and continued to sample every two minutes. When a solution turned a yellow brown colour I noted the amount of time it had taken to do so.
Hypothesis
I would expect that the breakdown of starch solution would reach optimum rate of reaction when the pH is neutral and gradually decrease either side of this neutral point. Therefore I would expect that tube 3 with a pH of 7 would react and break down the fastest. I came to this hyphothesis under the assumption that enzymes work best when at a neutral pH. Therefore the more acidic and alkali startch solutions should not react as quickly.
The change in pH would affect the ionisation of the side groups in the enzymes amino acid residues this would then affect the overall shape of the enzyme molecule and would then affect the efficiency of formation of enzyme-substrate complexes.
Results
Test Tube. pH. Colour at start. Colour at end. Time taken for colour to change.
1 9 Black Black n/a
2 8 Black Black n/a
3 7 Purple Yellow 540
4 4 Dark blue Brown 180
5 3 Black Black n/a
Time in minutes taken for colour to change/1 = rate of reaction
Variables
The independent variable is pH as I am adjusting the pH in each experiment, the pHs that are being used are 3, 4, and 6,8,10. With this different range of
You May Also Find These Documents Helpful
-
Enzymes are proteins that act as catalysts during a biochemical process. Catalysts are non-changing enzymes that can increase or decrease activation energy to accelerate or slow down a biochemical reaction without using additional energy.…
- 964 Words
- 4 Pages
Better Essays -
An enzyme is a protein that acts as a catalyst, a chemical agent that speeds up a reaction without being…
- 2988 Words
- 12 Pages
Better Essays -
Enzymes are specific protein molecules that catalyze a specific chemical reaction (facilitate the chemical reaction without being permanently changed in the process) by binding to a specific molecule called a substrate molecule. For example, amylase is an enzyme (found in your saliva and small intestine) that breaks starch (polysaccharide) molecules down into simple (monosaccharide) sugars like glucose. In this case, the starch molecules are the…
- 32334 Words
- 130 Pages
Powerful Essays -
Enzymes are known as protein catalysts. The name protein catalyst suggests that most enzymes are made of proteins. A catalyst is a substance that speeds up chemical reactions without being consumed in the process. (Giuseppe, M 2002, p.69). After a reaction has been catalyzed, the catalyst can be used again to catalyze the same reaction. Enzymes reduce the activation energy (minimal energy) it takes for a reaction to take place. Enzymes can either catabolize (destroy), or anabolize (build up) a chemical system.…
- 1445 Words
- 6 Pages
Good Essays -
References: Cell Membrane. Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 20 September 2011. Friday 28 Oct. 2011. <http://en.wikipedia.org/wiki/Cell_membrane>…
- 7879 Words
- 32 Pages
Powerful Essays -
Enzymes are catalysts that speed up chemical reaction but are not themselves consumed or changed by the reaction. The cell’s biological catalysts are proteins. Proteins are made up of one or more polypeptide chains that are folded to make an active site, an area in which a material to be acted on by the enzyme, called the substrate, will fit. The temperature,pH, the concentration of enzyme, and the concentration of substrate all affect the activity of the enzyme and the rate of the reaction.…
- 622 Words
- 3 Pages
Good Essays -
There are many types of enzymes and each has a specific job. Enzymes are particular types of proteins that help to speed up some reactions, such as reactants going to products. One of them is the amylase enzyme. Amylases are found in saliva, and pancreatic secretions of the small intestine. The function of amylase is to break down big molecules of starch into small molecules like glucose; this process is called hydrolysis. Enzymes are very specific; for example, amylase is the only enzyme that will break down starch. It is similar to the theory of the lock and the key. The enzyme is the lock and the key is the substrate; only the correct key could fit into the keyhole of the lock.…
- 1766 Words
- 8 Pages
Better Essays -
Usually iodine has a orange-yellow color, but iodine and starch react to produce a dark blueblack color, so iodine may be used as an indicator to show the rate at which starch is broken down.1 This occurs when polyiodide chains are formed from starch and iodine. However, as starch is hydrolyzed into smaller carbohydrate units, the blue-black color does not appear. Therefore, using this iodine test, the effects of pH on the function of amylase can be determined by the time it takes (if at all) for the iodine to remain its orange-yellow color.2…
- 2214 Words
- 9 Pages
Powerful Essays -
The follow experiment was prepared, conducted and analysed in order to test at which pH level starch will be digested at fastest. The digestive system is a complex network of organs as well as other structures which all work together to supply the body with the necessary nutrients and energy required. If problem occurs along the digestive tract the consequences can be fatal. Therefore it is extremely important to understand your body’s requirements and the way in which it functions, especially when engaging in one of the most crucial and rewarding activities; eating!…
- 2550 Words
- 11 Pages
Good Essays -
Enzymes are catalytic proteins. The purpose of a catalyst is to speed up metabolic reactions by lowering the free energy of activation or activation energy. Activation energy is known as the amount of energy needed to push the reactants over an energy barrier, so that the downhill part of the reaction can begin (Campbell 151). In an enzyme catalyzed reaction, the enzyme binds to its substrate, which is the reactant an enzyme acts on. In the reactions, the enzymes are very specific, where only a restricted region of the enzyme molecule binds to the substrate. This region is known as the active site (Campbell 152). The specificity of an enzyme results from its shape; the shape is form by the amino acid sequence since enzymes are proteins. If the shape of the substrate fits the shape of the active site, the enzyme will alters its shape so the active site embraces the substrate and maintains a firm grip, known as induced fit. This allows for great variations of enzymes.…
- 681 Words
- 3 Pages
Good Essays -
Enzymes are proteins that act as catalysts for reactions. This simply means that enzymes lower the activation energy required for a reaction to take place, allowing a particular reaction to take place much quicker and easier. Specific enzymes only lower the activation energy for specific reactions, and enzymes are shape-specific. The unique folds of the amino acid chains that make up an enzyme result in the formation of a specifically shaped active site. When the reactants of a reactions, called substrates, fit perfectly into the active site of an enzyme, the enzyme is able to catalyze the reaction. The activity of enzymes is affected by both the concentrations of enzymes present and the concentration of substrate present. As the amount of enzyme present increases, the rate of reaction increases. Furthermore, as the amount of substrate increases, the rate of reaction will initially increases. Most enzymes require specific environmental conditions to be met in order for them to function properly and efficiently. These conditions include temperature, then concentration of salt, and the pH level. If the optimum conditions for an enzyme are altered, the enzyme may denature, or change its shape, and deactivate. As a result, the enzyme would no longer to be able to catalyze the reaction, and the reaction rate would significantly decrease ("Worthington Biochemical Corporation").…
- 2125 Words
- 9 Pages
Better Essays -
Enzymes are a protein serving as a catalyst, a chemical agent that changes the rate of the reaction without being consumed by the reaction. Enzymes are proteins made up of long chains of amino acids. These form complex shapes. The enzymes are individuals, like the different players on a ball team, they have different specific structures and jobs. As one ball player may be very tall and one short, the specific different shape of the active site on an enzyme is unique and prepares it to mix with a certain substrate. Without enzymes, the process of metabolism would be hopelessly slow. The reactant an enzyme acts on is referred to the enzyme 's substrate. The enzyme will combine with or to its substrate. While the two are joined, the substrate is converted to its product by catalytic action of the enzyme. There is an active site of the enzyme molecule which is a restricted region that actually attaches to the substrate. Usually the active site is formed by only a few of the enzyme 's amino acids, the rest is just the framework that reinforces the active site. In an enzymatic reaction, the substrate enters the active site then is held in place by weak bonds. Now the enzyme does its work and first changes shape so it can hold onto the substrate. Next the substrate is changed to its product, the product is released and the enzymes active site is ready and waiting for another molecule of substrate.…
- 1062 Words
- 4 Pages
Better Essays -
Buffer A and buffer B were prepared first with the concentration of Buffer A being roughly half that of Buffer B. The preparation of Buffer A is as follows: 100 mL of 0.75 M NaAc solution, 100 mL of 0.22 M HAc…
- 757 Words
- 4 Pages
Good Essays -
Enzymes are specific-type proteins that act as a catalyst by lowering the activation energy of a reaction. Each enzyme binds closely to the substrate; this greatly increases the reaction rate of the bounded substrate. Amylase enzyme, just like any other enzyme, has an optimum PH and temperature range in which it is most active, and in which the substrate binds most easily.…
- 2678 Words
- 11 Pages
Better Essays -
Enzymes are globular proteins, they are responsible for most of the chemical activities of a living organism. They act as catalysts, substances that affects the reaction of other substances without being destroyed or altered during the process. They are extremely efficient in the body system of living organisms, one enzyme may catalyse over a thousand chemical reactions every second. But there are certain conditions that need to be fulfilled in order for the enzymes to work. Temperature of the environment must be correct for each enzyme because different enzymes will have different temperature ranges in which they can live. pH levels in the environment must also be correct because if the environment around the enzyme is too basic or acidic, the enzyme will quickly denature.…
- 1408 Words
- 6 Pages
Good Essays