Buffer solution making and investigation.
Buffer solution making and investigation Aim I will attempt to prepare two buffer solutions. The first buffer solution will have a pH value of 5.2 and will be made from a mixture of 1.0M ethanoic acid and 1.0M sodium ethanoate solution. The second buffer solution will have a pH value of 8.8 and will be made from a mixture of 1.0M ammonia and 1.0M ammonium chloride solution. Plan In order to make these buffers, I will need to calculate the exact proportions of salt solution and acid/alkali to add in order to obtain the necessary pH value: pH = pKa - log [HA] [A-] Given that: The pKa value for 1.0M ammonia and 1.0M ammonium chloride solution is 9.3. The pKa value for 1.0M ethanoic acid and 1.0M sodium ethanoate solution is 4.8. For the making of the buffer pH 5.2: Equations for the dissociation of ethanoic acid and sodium ethanoate respectively: CH3COOH + H2O - CH3COO- + H3+O CH3COONa › CH3COO- + Na+ Using the equation previously stated: 5.2 = 4.8 - log [HA] [A-] 5.2 - 4.8 = - log [HA] [A-] 0.4 = - log [HA] [A-] 0-0.4 = [HA] [A-] 0.398 = [HA] : [A-] CH3COOH + H2O - CH3COO- + H3+O (100 - x) x x = 0.398/1 00 x 0.398 = 28.46 cm3 salt .398 Therefore: 00 - 28.46 = 71.54 acid For the making of the buffer pH 8.8: Equations for the dissociation of ammonia and ammonium chloride respectively: NH3 + H2O - NH2- + H3+O NH2Cl › NH2- + Cl- Using the
Penicillin Enrichment of Listeria monocytogenes pathogenicity mutants.
Penicillin enrichment of Listeria monocytogenes pathogenicity mutants 9906035 University of Warwick, Coventry, Warwickshire Penicillin Enrichment of Listeria monocytogenes pathogenicity mutants Listeria monocytogenes is a facultative intracellular pathogen. This project aimed to produce strains that were defective for intracellular growth by mutagenising a culture with ultra violet light and nitrosoguanidine. Intracellular mutants were selected for using a method of ampicillin enrichment. Approximately 200 colonies survived the enrichment process but only four colonies were characterised. These putative mutants, as well as nine putative mutants isolated from a previous experiment, were used to infect a culture of the mouse fibroblast cell line, L2, to look for mutants that generate small plaques. Unfortunately this infection was unsuccessful, but the generation times of the putative mutants were calculated. One mutant had a slow generation time of 88.2 minutes, three had fast generation times of 43.8, 39.6 and 33.6 minutes. The rest had relatively normal generation times of 60 minutes. INTRODUCTION Listeria monocytogenes is a facultatively intracellular, gram positive, food-borne pathogen. Infection with L. monocytogenes can cause listeriosis, a relatively rare disease, which can be fatal to the fetus in pregnant women, or can present it self as meningitis in the
The Effect of copper sulphate on the activity of catalase.
Title: The Effect of copper sulphate on the activity of catalase. Aim: The aim of this experiment is to determine how copper sulphate affects the activity of catalase through the decomposition of hydrogen peroxide into water and oxygen gas. The activity of catalase can only be determined by the volume of oxygen evolved in the decomposition of hydrogen peroxide. The enzyme catalase is an oxidase that catalyses the decomposition of hydrogen-peroxide to form water and oxygen. H2O 2 H2O + O2 In the above reaction, hydrogen-peroxide acts as the substrate, when mixed with the enzyme catalase (which will be yeast in the experiment). The hydrogen-peroxide and catalase will then react to form an enzyme-substrate complex which results to the formation of two products which are water molecule and oxygen gas. The inhibitor used in this experiment will be copper sulphate which will have effect on the activity of catalase. The activity of catalase can be measured by measuring the amount of oxygen produced when mixed with hydrogen-peroxide. The resulting effervescence can be exploited to measure the rate of enzyme reaction. Method The basic reaction mixture contains simply hydrogen peroxide (substrate) and yeast (as the source of enzyme) with or without copper sulphate. Adding yeast will start the reaction, and then the measurements will be taken
The Energy Levels of Molecules
The Energy Levels of Molecules The phenomena of chemistry cannot be understood thoroughly without a firm grasp of the principle concept of quantum mechanics. When talking about energy levels, quantisation has to be considered, and this quantisation is the basic assumption of Quantum theory. This is when all the energy levels are quantised meaning that they can have only discrete values. This quantisation is defined through a quantum number, which usually have integers or half integers as values. These quantum numbers can only be fixed values whereas a classical particle can have any value when changing from one energy level to another. The molecule normally accepts one quantum of energy and the size of this quantum must be exactly the same as the difference between these two levels. Therefore this statement describes us the quantisation of energy. An element can only be present in certain energy levels corresponding to various quantum states (as shown below), but the energy of an electron cannot be found between any shown levels. Energy quantisation is universal because it holds for all kinds of systems like atoms, nuclei, molecules or electrons in solids. The principle energy levels of electrons Shell Principle Quantum Number Period (horizontal row) Maximum Number of Electrons = 2n2 Energy sublevels K 2 S L 2 2 8 S p M 3 3 - 4 8 S p d N 4 4 - 6 32 S p
In this essay I am going to explore the functions of carbohydrates within the body and plants. It will give me a chance to explain and understand fully the role of carbohydrates and, how the structure of a carbohydrate can help the structure of a cell
Functions of Carbohydrates within the body. In this essay I am going to explore the functions of carbohydrates within the body and plants. It will give me a chance to explain and understand fully the role of carbohydrates and, how the structure of a carbohydrate can help the structure of a cell; whether it maybe a plant or an animal cell. For example, ggreen plants use the energy of sunlight to convert carbon dioxide and water into carbohydrates. This process, called photosynthesis. Carbohydrates have a variety of different functions; they are vital as a source of the body's energy. I will look in more detail of this later. There is an endless amount of possibilities of all the carbohydrates that are found in nature, so it will not be possible to mention them all. I therefore intend to concentrate on the main carbohydrates, which are frequently used in nature. Carbon, Hydrogen, and Oxygen are the main organic compounds, which compromise or rather forms the make up of a carbohydrate. These can be either in the form of aldehydes or ketones. Carbohydrates have a main general formula of Cx(H20)y. Carbohydrates are divided into three main groups, known as monosaccharides, disaccharides,and polysaccharides. The functions of carbohydrates in natures are variable, however serve a main purpose in the function of storage and liberation of energy; in both animals and
Observe the effect of temperature on activity of the enzyme amylase.
Investigating enzymes Aim The aim of the experiment was to observe the effect of temperature on activity of the enzyme amylase. Introduction The experiment is focussing on the effect of different temperatures upon the activity of the enzyme amylase. Amylase is found in saliva and in the pancreas. It hydrolyses starch to maltose. Starch is the substrate, and it is a polysaccharide, it is broken down into maltose, which is a disaccharide by amylase. Amylase is a protein made up of chains of amino acids. The diagram below shows how enzymes work: In the experiment, to test the effects of temperature on the activity, the starch will be hydrolysed in to maltose with the enzyme Amylase. Fearons reagent was added to produce a colour. This colours intensity shows how much maltose is present. To determine the colour intensity, a colorimeter was used to provide the amount of light absorbance from the samples. Hypothesis The activity of the enzyme will be affected by temperature. The peak activity will be around 40oC. The activity will fall sharply above 40oC. Apparatus 0.5 % starch buffered to pH 6.7 % NaCl solution Fearons reagent 20% NaOH solution pH 6.7 buffer Amylase solution Distilled water Tongs Boiling tubes Boiling tube rack 00 cm3 measuring cylinder , 5 and 10 cm3 pipettes and safety pumps Gloves Goggles Cuvettes Stop clock Colorimeter Ice Bath (0
The Effects of Varying Starch Concentration on a Solution of Amylase: Measurement of Enzymatic Rate Changes Using IKI.
ABSTRACT The Effects of Varying Starch Concentration on a Solution of Amylase: Measurement of Enzymatic Rate Changes Using IKI. Brooke Good Student, Functional Biology, Section 1003, Southwest Texas State University, San Marcos, TX 78666 The relationship between starch concentration and the enzymatic rate of amylase were investigated. Nine experimental assays were created all of which contained a solution of IKI, starch, saliva, and pH buffer. The nine assays were set up under four separate conditions containing a varying dilution of a 1 % starch concentration. The assays were then timed and their IKI absorbencies were noted. The assays containing the greatest percent starch concentration, 1%, had the highest enzymatic rate. As starch percentage was decreased enzymatic rate decreased. It was concluded that starch concentration has a direct effect on the enzymatic rate of amylase. The findings were consistent with experiments of the past of this nature performed by early scientist. INTRODUCTION Enzymes are perhaps one of the most important proteins of the human body. Enzymes such as amylase, an enzyme that breaks down carbohydrates, work by means of surface catalysis. In other words, the surface of the enzyme enables other molecules to react in a manner they would not be able to without the surface of the enzyme present. Enzymes achieve this by lowering the
Copper can be extracted from low-grade ore (CuFeS2) by means of bacterial leaching.
Copper can be extracted from low-grade ore (CuFeS2) by means of bacterial leaching. The low-grade ore and tailings are put onto an area of impermeable ground. This is then covered in an acidic leeching solution that contains the bacteria, T. ferro-oxidans and T. thio-oxidans. These bacteria are best suited to an acidic environment. All the bacteria need are Fe2+ ions or S2- ions, oxygen, carbon dioxide and bacterial nutrients containing phosphorus and nitrogen. The final result is that the bacteria convert the insoluble chalcopyrite into a solution containing Cu2+, Fe2+, Fe3+ and SO2- ions. The solution carrying the copper ions can be straightforwardly drained off as it is on an impermeable base layer. The Cu2+ is removed from the solution by ligand exchange solvent extraction. This is where the ligand, a compound with a lone pair of electrons, binds to metal ions. A complex is then formed with the metal ion in the centre surrounded by the lignads. The Fe2+ and Fe3+ ions are left behind in the aqueous solution. A compound that is a good ligand for copper ions is dissolved in an organic solvent immiscible in water, such as kerosene. When this solution is mixed with the copper ions dissolved in water, this reaction takes place: Cu2+(aq) + 2LH (organic) ? CuL2 (organic) + 2H+(aq) L = Ligand This process moves the copper ions from the water, where they are at a low
What are Cytotoxic T Lymphocytes?
What are Cytotoxic T Lymphocytes? Lymphocytes are one of the five types of white blood cells circulating in the blood. Although they look very similar they are extraordinarily diverse in their functions. The most abundant forms are B and T cells. The B cells are produced and mature in the bone marrow. In comparison the precursors of T cells leave the bone marrow and mature in the Thymus. B and T cells are specific to particular antigens (they are able to recognise and bind to precise molecular structures via receptors). Most of the T cells in the body belong to one of two subsets. These are distinguished by the presence on their surface of one or the other of two glycoproteins designated: * CD4 * CD8 Which of these molecules is present determines what types of cells the T cell can bind to. * CD8+ T cells bind epitopes that are part of class I histocompatibility molecules. Almost all the cells of the body express class I molecules. * CD4+ T cells bind epitopes that are part of class II histocompatibility molecules. Only specialized antigen-presenting cells express class II molecules. These include:dendritic cells, phagocytic cells like macrophages and B cells! CD8+ T cells The best understood CD8+ T cells are cytotoxic T lymphocytes (CTLs). They secrete molecules that destroy the cell to which they have bound. This is a very useful function if the target cell is
The biology of Fusarium oxysporum f. sp. gladioli, causal agent of corm rot of Gladiolus corms
Chapter Two The biology of Fusarium oxysporum f. sp. gladioli, causal agent of corm rot of Gladiolus corms Abstract Gladiolus corm rots disease caused by F.oxysporum f.sp. gladioli results in severe crop lossess in many parts of the world. The problem is increasing owing to the lack understanding of the physiological and ecological factors affecting on of F.oxysporum f.sp. gladioli. Different physiological factors as Temperature, Ph, Nutrition, Water activity were employed to understand their effects on F. oxysporum f. sp. gladioli. Results showed that, the strains responded diversely to the different Physiological factors. The optimum temperature for G010 was 20-250 C, and 8 pH. However the optimum growth for 640, 160 strains were 25-300 C, and pH 4. PDA was the best suitable media for all isolates[A1]. Briefly there are differences between F.oxysporum f. sp. gladioli strains and they are differing in their needs. Those differences could affect on the pathogenity. Introduction Most known fungal species are strictly saprophytic, with less than 10% of the more or less 100.000known fungal species able to colonize plants Carlile et al. (2001). Plant parasitic fungi have dominated the living plants as an abundant source of nutrients ( Mendgen et al., 1996). But there is a different level of specialization in plant-fungal interaction. The first group include involves true