Enzymes Investigation

name enzyme was suggested in 1867 by the German physiologist Wilhelm Kühne (1837-1900); it is derived from the Greek phrase en zyme, meaning "in leaven." Those enzymes identified now number more than 700. Enzymes are classified into several broad categories, such as hydrolytic, oxidizing, and reducing, depending on the type of reaction they control. Hydrolytic enzymes accelerate reactions in which a substance is broken down into simpler compounds through reaction with water molecules. Oxidizing enzymes, known as oxidases, accelerate oxidation reactions; reducing enzymes speed up reduction reactions, in which oxygen is removed. Many other enzymes catalyze other types of reactions. Individual enzymes are named by adding ase to the name of the substrate with which they react. The enzyme that controls urea decomposition is called urease; those that control protein hydrolyses are known as proteinases. Some enzymes, such as the proteinases trypsin and pepsin, retain the names used before this nomenclature was adopted. Properties of Enzymes As the Swedish chemist Jöns Jakob Berzelius suggested in 1823, enzymes are typical catalysts: they are capable of increasing the rate of reaction without being consumed in the process. See Catalysis. Some enzymes, such as pepsin and trypsin, which bring about the digestion of meat, control many different

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  • Level: AS and A Level
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Enzymes Investigation

Steven Vickery 11E SC1 Biology Practical Investigation Hypothesis; Enzymes are biological catalysts. They speed up chemical reactions, which take place inside living things. Molecules are constantly moving about and bumping into each other. Now when a substrate molecule bumps into a molecule of the right enzyme, it fits into a depression on the surface of the enzyme molecule. This depression is called active site. The reaction then takes place and the molecules of product leave the active site, freeing it for another substrate molecule. In this investigation we are going to see what the atmosphere and the environment have on the breaking down of proteins via a protein-digesting enzyme. Safety Precautions; To make sure this experiment is safe, I have decided that the water bath temperature range during the experiment will not cause physical damage (e.g. scolding). The protein digesting enzyme bottle will also be clearly marked as,"Harmful if swallowed". Steps will also be taken so passers by will not accidentally drink the enzyme. I shall do this by labelling the substances I obtain. Fair Test; Before I proceed with the Experiment, I have taken into account the following; . It is important that all apparatus for this experiment is clean and will rinsed prior to each experiment. 2. All chemicals used will be checked to make sure that no obvious signs of

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Enzymes Investigation

Introduction Enzymes are proteins that speed up the rate of reaction at physiological temperatures without being used up or changed themselves. The nature of neither the end product nor the reaction equilibria is changed by the enzyme, just the rate at which it is reached. They are globular proteins, composed of polymers of amino acids. Enzymes act by becoming part of the reaction, creating a new pathway with a lower activation energy (EA), than the than the energy needed to carry out the original reaction, as seen in the graph to the left (Campbell, 1996). The active site of an enzyme is actually a very small proportion of the total volume. The substrate binds to the active site, forming an enzyme-substrate complex. The substrate is held in place by weak interactions such as hydrogen bonds and ionic bonds. The substrate is converted to the product and then leaves the active site, freeing it to take up another substrate molecule. As the enzyme is neither used up nor changed in the reaction it means a very small amount of enzyme can have a huge effect. Enzymes are usually specific and catalyse on particular type of reaction or even only one specific reaction. This specificity is down to the active site, when an enzyme binds to the appropriate substrate, subtle changes in the active site occur. This alteration of the active site is known as an induced fit. Induced

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Enzymes Investigation

Planning What am I trying to find out I 'am trying to find out what the optimum temperature for the enzyme 'catalase' (which is in the liver) is in breaking down Hydrogen Peroxide (2H2O2) into water and oxygen (2H2O + O2) this process is called decomposition. I will also try to find out the volume of oxygen that there will be in thirty seconds. What are Enzymes? The chemical reactions of metabolism would go very slowly or not at all, if it were not for enzymes, enzymes are large proteins that speed up chemical reactions inside a cell, but the enzyme itself is not used up in the reaction this allows the enzyme to do the same thing over and over again. In their globular structure, one or more polypeptide chains twist and fold, bringing together a small number of amino acids to form the active site, or the location on the enzyme where the substrate binds and the reaction takes place. Enzyme and substrate fail to bind if their shapes do not match exactly. This ensures that the enzyme does not participate in the wrong reaction. The enzyme itself is unaffected by the reaction. When the products have been released, the enzyme is ready to bind with a new substrate. The temperature and ph level affects enzymes. Uses of Enzymes Alcoholic fermentation and other important industrial processes depend on the action of enzymes that are produced by the yeasts and bacteria used in the

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Enzyme Concentration

Enzyme concentration Aim In this experiment, the purpose is to investigate how enzyme concentration can affect the initial rate of reaction. By doing this I will be able to develop experimental and investigate skills, including risk assessment. Hypothesis The effect of reducing the concentration of the protease enzyme on the rate of breakdown of the protein found in the milk powder is that the enzymes will run out of energy which will mean less milk powder will be broken down as they have smaller energy over the time. Equipment * Milk powder solution * Test tubes * Test tube holder * Stop clock * Standard protease solution 1% * 5cm? pipettes * Glassware for diluting enzymes Safety All enzymes are potential allergens. Handle with care to minimize skin contact and inhalation. Also wear safety gear such as goggles and aprons. Procedure * Pour 2cm? of protein solution into a cuvette using a pipette. * Then pour 2cm? of the protease solution in to a cuvette using another pipette. Mix carefully and quickly put into the colorimeter and start the stop clock. * Measure the absorbance every 30 seconds for 5 minutes or in till there is a little change in the reaction and record the result. * Get rid of the mixture and rinse the cuvette with distilled water. * After recording the result for every 30 seconds of all the 5 minutes plot a graph of the change in

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Induction of beta-galactosidase

Induction of ß-galactosidase Hypothesis and aims By carrying out this experiment I plan to show that in the absence of lactose, the enzyme ß-galactosidase will not be made and the mixture I use to test for this will be colourless. The main aim of the experiment is to demonstrate practically the switching on of a gene. Method To test this hypothesis I will use the bacterium E.Coli which produces the enzyme ß-galactosidase when lactose is present. I will go into the details of how and why later. This is the apparatus, equipment and method I will use. A tick indicates that the named substance will be put into the test tube in question. Test tube cm3 E. Coli without lactose cm3 E. Coli with lactose cm3 Distilled water cm3 ß-galacto- sidase cm3 ONPG 5 drops Methyl- benzene 5cm3 Sodium Phosphate Colour at start Colour at end ? ? ? ? Colourless 2 ? ? ? ? Colourless 3 ? ? ? ? Colourless 4 ? ? ? ? Yellow The lac operon is the classic example of gene regulation, in which the production of ß-galactosidase (lactase) is induced by the presence of lactose in the growth medium. In this practical task, ONPG, rather than lactose is used as a substrate for the enzyme. After partial disruption of the cell membrane with methylbenzene (toluene), colourless ONPG is added. The ONPG moves into the cells where it is broken down by the enzyme to form

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Induction of Beta-galactosidase

Induction of Beta-galactosidase Aim: This investigation aims to induce and measure the production of the enzyme beta-galactosidase by E. coli. Scientific Background: Cells only express genes when the protein products they code for are needed, thus conserving energy and resources within the cell. The bacteria Escherichia coli (E. coli) can use different carbohydrates as a food source. If lactose, the disaccharide found in milk, is present in the growth medium it must be broken down into the monosaccharide glucose and galactose before it can be utilized as an energy source in respiration. E. coli has a gene for an enzyme called Beta-galactosidase that breaks down the lactose. The presence of the lactose switches on this gene so the enzyme is produced. Beta galactosidase is the enzyme responsible for the first step in the breakdown of lactose. Since beta-galactosidase is a protein, its structure is determined by the information stored in a DNA molecule. There are several steps required to transfer the information stored in a DNA molecule into the structure of a protein. The first is transcription; transcription involves copying the code in a DNA molecule into a messenger RNA molecule. This process occurs in the nucleus of the cell. Then the translation of this message into the sequence of amino acids in beta galactosidase occurs in the cytoplasm at the ribosome. Once the

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Induction of beta-galactosidase

Induction of beta-galactosidase Hypothesis: By adding lactose to the food source of Escherichia Coli, we will introduce the need for ß-galactosidase in the bacteria. The presence of lactose will overcome the forces holding the repressor molecule to the gene which will code for the amino acids which will form the enzyme, therefore the RNA polymerase will be able to bind to the gene and cause the DNA to unwind, allowing mRNA to be produced that codes for the genes. Once the enzyme is produced, it will break down the disaccharide lactose into the monosaccharides glucose and galactose, which are then used in respiration. We will add ONPG to the mixture, which is also catalysed by ß-galactosidase into galactose and GNP, a yellow chemical. The presence of ONP will prove that ß-galactosidase is present in the mixture. Therefore upon adding lactose to a mixture of bacteria and ONPG, ONP will be produced. Aim: We will attempt to find out whether adding lactose in with bacteria will cause the genes which code for beta-galactosidase to be unlocked, ß-galactosidase to be produced and the lactose to be digested into glucose and galactose. Safety Precautions: * Wear gloves and lab coat at all times. * Ensure area used is thoroughly sterilised and there are no stray chairs or bags on the floor and the desk is entirely clear. * Ensure all equipment to be used is sterile. *

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  • Subject: Science
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Investigation On Osmosis

Investigation On Osmosis By Alex Rignall Investigation On Osmosis Aim To investigate how much change there is in the mass of a potato chip in varied concentrations of a sucrose solution. Prediction Osmosis: Osmosis is the movement of any of the solutions molecules from a region in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a cell membrane or a partially permeable membrane, which lets small molecules through and does not let large ones through. I predict that the lower the concentration of sucrose in the solution the more the potato chips will expand. I can say this because I know that there will be more water molecules and therefore osmosis will take place between a lower concentration of water molecules and a higher concentration of water molecules that are separated by a partially permeable membrane such as a the cell membrane of the potato. The sucrose will not cross the partially permeable membrane because the molecules are too big to fit in between the gaps in the membrane. The higher the concentration of sucrose in the solution the more the chips will decrease in mass. I can predict this because from my previous prediction I know that the potato chip will have a higher concentration of water molecules, and therefore the water molecules in the potato chips will move across the partially

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Investigation into the effect of enzyme concentration of catalysers of sucrose by sucrase.

Investigation into the effect of enzyme concentration of catalysers of sucrose by sucrase Planning Aim: I aim to find out the effect of enzyme concentration on the substrate. I will try to find out how fast the substrate sucrose is broken down using different concentrations of sucrase, to see if there is a link between enzyme concentration and the rate at which the substrate is broken down. An enzyme is made of protein, they are protein molecules which are called a biological catalyst. These molecules speed up chemical reactions and remain unchanged when the reaction is finished. Enzymes have an active site, this is a place where another molecule or molecules can bind to. These molecules are the substrate of the enzyme. The shape of the enzymes active site will allow the substrate to fit onto it. The substrate is held in place by temporary bond that form between the enzyme and the substrate, the bonds form between the R-groups of the enzymes amino acids and the substrate. Only one type of enzyme will work on one type of substrate molecule. This is because the shape of the enzymes active site will only fit the molecule which will fit into its active site. The enzymes catalyse reactions where substrate molecules are split into two or more molecules. In this case Sucrose glucose + Fructose Sucrose is broken down into two molecules by sucrase into glucose and fructose

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