...Acis CHEMICAL REACTIONS: ACID-BASE BUFFERS Short Overview Acids and bases represent two of the most common classes of compounds. Many studies have been done on these compounds, and their reactions are very important. Perhaps the most important reaction is the one in which an acid and base are combined, resulting in the formation of water (in aqueous solution) and a salt; this reaction is called neutralization. A buffer solution is a solution that contains both an acid and a salt containing the conjugate base anion in sufficient concentrations so as to maintain a relatively constant pH when either acid or base is added. In this experiment you will prepare a buffer solution and observe its behavior when mixed both with an acid and a base. You will also compare the behavior with that of solutions containing only the acid. Theory In his theory of ionization in the 1880’s, Svante Arrhenius defined acids are substances which form H+ and bases as substances which form OH- in water. He further defined a salt as a substance other than an acid or base which forms ions in aqueous solution. Such substances are thus capable of producing an electric current and are called electrolytes. The amount of electricity produced is directly proportional to the concentration of ions in solution. With regard to electrolytes we have learned previously that strong acids and strong bases ionize completely, and are therefore strong electrolytes because they...
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...Chromatography INTRODUCTION IN THIS LAB, WE WILL BE EXPRESSING THE GREEN FLUORESCENT PROTEIN (GFP) IN BACTERIA AND PURIFYING IT USING COLUMN CHROMATOGRAPHY. THE SPECIFIC TYPE OF CHROMATOGRAPHY WE WILL BE USING IS HYDROPHOBIC INTERACTION CHROMATOGRAPHY (HIC). THE FOLLOWING IS INFORMATION FROM BIO-RAD INC., THE SUPPLIER OF THE REAGENTS: GFP has several stretches of hydrophobic amino acids, which results in the total protein being very hydrophobic. When the supernatant, rich in GFP, is passed over a HIC column in a highly salty buffer (Binding Buffer), the hydrophobic regions of the GFP stick to the HIC beads. Other proteins which are less hydrophobic (or more hydrophilic) pass right through the column. This single procedure allows the purification of GFP from a complex mixture of bacterial proteins. Loading the GFP supernatant onto the chromatography column When students load the GFP supernatant onto their columns, it is very important that they do not disturb the upper surface of the column bed when performing the chromatography procedure. The column matrix should have a relatively flat upper surface. A slightly uneven column bed will not drastically affect the procedure. However, subsequent steps of loading, washing, and eluting should minimize disrupting the column such that beads "fluff up" into the buffer. When loading the GFP supernatant onto the column, the pipette tip should be inserted into the column and should rest against the side of the column...
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...Introduction Buffer is a solution that resists a change in pH when bases or acid are added. Solutions that are acidic contain high concentrations of hydrogen ions (H+) and have pH values less than seven. Buffer usually consist of a weak acid, and its conjugate base or a weak base and its conjugate acid. The function of buffer is to resist the changes in hydrogen ion concentration as a result of internal and environmental factor. This buffer experiment is important so that we relies the important of buffer in our life. Besides that, it is also important so that we master the buffer preparation techniques and can conduct the experiment ourselves without anyone to instruct us. Other than that, we got to learn how to operate a pH meter and we...
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...carbohydrates, lipids and proteins is the production of acids ( organic acids, volatile acids and fixed acids). These acids if not neutralized would influence the physiologic pH of blood and tissues of the body. Therefore, a buffer system must be available to prevent the accumulation of these acids and to inhibit their harmful effects. This chapter describes the mechanism and action of buffers in maintaining the proper pH in health and in disease states. Definitions (Review of basic concepts) 1. Acids: Compounds that release hydrogen (proton donors) 2. Bases: Compounds that accepts hydrogen (proton acceptor) 3. Strong Acids: Compounds with weak affinity to H+ (release all H+ ions) 4. Strong Base: Compounds with strong affinity to H+ (Bind H+ ions) 5. The dissociation constant K: It reflects the strength of an acid or base. The larger the K value, the greater the dissociation of H+ ions, thus the stronger the acid. 6. pK: is the negative log of K. The smaller the pK the stronger the acid (Strong acids has a pK 9.0) 7. Buffers: A combination of weak acid and its conjugate base (salt). It resists change of pH upon addition of small amounts of strong base. 8. The Handerson-Hasselbalch equation: It governs the mechanism of a buffer system. For the weak acid HA, it dissociates as follows: HA -----------> H+ + A- The Handerson-Hasselbalch equation is written as follows: A- pH = pK +...
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...the population will be homozygous dominant? Q2 = 98/200 = 0.49 Q= 0.7 P+q=1 => p=0.3 => p2 = 0.09=9% Ex2: Brown hair (B) is dom to blond hair (b). If there are 168 with brown hair in a population of 200. What is the predicted freq of heterozygotes? P2 + 2pq = 168/200 P2 +2pq = 0.84 P2 +2pq + q2 =1 => q= 0.4 2pq =? 1-q= 1-o.4=0.6p => 2 x 0.4 x 0.6 = 0.48=> 48% Lab 12 GTE: + glucose: creates isotonic environment + Tris: pH buffer ( pH=8) ideal pH for DNA not RNA + EDTA: binds divalent cations inhibits Dnase: requires cations factor +SDS: denatures proteins ( irreversible) dissolves membranes +NAOH: degrades cell wall, denatures DNA ( reversibly) +KOAc: neutralizes( renatures plasmid DNA- not chromosomal DNA) Precipitates debris, lipids, denature proteins&DNA Supernatant: plasmid, salts, some proteins, RNA. +Isopropanol: precipitate DNA. Pellet: DNA, salt, RNA. Sup: proteins +Ethanol: precipitate DNA&RNA Wash away salt...
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...is a chemical, we can do reactions with it just like we can work with any other chemical. In this lab, we will use the chemical properties of DNA to extract it from the cells of onions. Experiment: Note: You should write all observations from this lab in the observation section on the third page of this lab. These observations will account for a large part of your grade, so be neat and complete! 1) Prepare a buffer solution by pouring the following into a clean 250 mL Erlenmeyer flask: - 120 mL of water (distilled water, if available) - 1.5 grams of sodium chloride (table salt) - 5.0 grams of baking soda (sodium hydrogen carbonate) - 5.0 mL of shampoo or liquid laundry detergent What buffer solutions are used for: This buffer solution is used in this lab for several reasons. First of all, the saltiness and acidity (pH) of the solution is very close to that in living things; as a result, the DNA will like to dissolve into this solution. Secondly, the detergent is added to help break down cell walls in the onion cells. Cell walls in living things are made of long polar molecules with a “greasy” end and a charged end. Because detergent is used to break apart greasy particles in your clothes, it will also work to tear apart the “greasy” molecules in cell walls. It will be important that these cell walls break down in this lab, because...
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...students will explore the principles of inorganic chemical phenomenon including partially soluble substances, weak acids and bases, buffer systems and redox reactions. In addition, a basic understanding of the chemistry of the biologically important elements (H, C, N, O, K, Na, Ca, Mg, P, S, Cl and some transitional elements) will be explored. Course Learning Outcomes Upon successful completion, students will be able to: • Predict cation and anion concentrations of partially soluble solids dissolved in pure water and in a solution containing a common ion. • Apply knowledge of acids and bases in order to predict the pH of a solution containing a weak acid or base. • Demonstrate the use of common pH and redox indicators in microbiological media. • Select appropriate reagents to make a buffer having a desired pH. • Determine which compounds undergo the process of reduction and which undergo the process of oxidation. • Describe the basic chemistry of the predominant biologically important elements and their function(s) in microbiological systems. Dr. Andrew Baer Office Hours Monday: 10:30 am – 11:20 am Wednesday: 1:30 pm – 2:20 pm Thursday: 9:30 am – 10:20 am or by appointment Email: abaer@centennialcollege.ca Textbook: Hage, D.S and Carr J.D Analytical Chemistry and Quantitative Analysis, Prentice Hall, 2011 (optional) CH 125 Lab Manual (available on eCentennial) Additional References: Harris, Daniel C., Exploring Chemical Analysis, 5th Ed., W. H. Freeman...
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...concept to the measurement of hardness in water. To determine the total hardness for water and test for Ca and Mg solutions and unknown samples. Introduction Hardness of water is a property caused by the presence of polyvalent metal cations, primarily Ca2+ and Mg2+ in natural waters. Hardness is undesirable in a water supply because it results in scale formation and in soap wastage (Sample Lab, Fiu). If one ever has gone to a place where ground water is abundant and is used for drinking and cooking, one can see that the pots have a white mark done to the long exposure to the metals that these water contains, or the shampoo doesn’t produce bubbles. Chelation process is usually the one used most frequently to measure water hardness. The metal ions in this water may have electrons that can be shared in pairs with a donor to form a coordination bond. If a molecule or ion has more than one "free" electron pair which can be shared with a metal ion or similar species, it is called a chelating agent. The complex is termed a chelate. The chelating reagent that we will be using in this lab is EDTA (ethylene-diamine-tetra-acetic acid ). This reagent is the most commonly used for this purpose. As the name inplies, EDTA is a an acid, a tetraprotic one. In the completely deprotonated form, EDTA can form coordination bonds at six sites, and the resulting metal complexes are very stable. If the deprotonation of EDTA is not complete, these chelates are not as stable. In the determination...
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...acts as a buffer against any possible changes in the pH from acids produced from bacteria, maintaining the oral cavity at an almost neutral pH level.(3) If saliva was introduced to a differing pH than its optimal pH, it would cause the amylase action to either decrease or cease functioning all together if the pH changed dramatically enough. With the given information, it could be said that salivary amylase would be at its optimal functioning level at around the average saliva pH of 6.78.(1) A change in pH would be detrimental to amylase given the protein nature of amylase and the instability of proteins in more acidic or basic pH concentrations.(3) When proteins are surrounded by an acidic pH, they become unstable due to the increase in positive charge from the disassociated hydrogen ions, the positive charge acting to pull the proteins out of their folded shape.(3) In similar opposition, when proteins are surrounded by a basic pH, they are instead pulled apart by the negative charge produced by the increased amount of hydroxide ions.(3) Methods: In this experiment, a saliva solution was procured by first rinsing the mouth with distilled water, then taking another quantity of distilled water into the mouth and mixed with saliva for 2 minutes. The prepared saliva wash was spit into a dixie cup and diluted with distilled water with roughly a 1:2 ratio of saliva solution to distilled water. Next, 7 test tubes were pipetted with 2.5 ml each of a specific pH buffer. Tube 1...
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...electrophoresis. NOTE: Read and all the instructions carefully before starting your experiment. Facilitators will guide you on the use of PCR machine and agarose gel electrophoresis. Be cautious when there is a need to handle items/equipments and the hazardous reagent, Ethidium Bromide (EB) in the EB room. Materials: Agarose gel electrophoresis set DNA ladder (marker) DNA loading dye DNA samples (labelled as DNA 1 and DNA 2; DNA 2 is obtained from P3) Deionised water Ice in tub Biohazard bin Disposable pipette tips Gloves Microcentrifuge (table top) Micropipettes (P1000, P100, P20) Microcentrifuge tubes (1.5ml) Paper Towels PCR machine PCR master mix (Taq Polymerase, MgCl2, dNTPs, buffer) Primers (labelled as Primer 1 and Primer 2) Methods: LAB 1: AM session (9.15am to 12noon) Part A: The Polymerase Chain Reaction (PCR) As a team, you will be using TWO DNA samples to perform TWO PCR reactions; DNA 1 will be given and DNA 2 which is obtained from your P3. NOTE: If you have TWO DNA samples from P3, choose the ONE with better purity or quantity. 1. Refer to Table 1 and complete the components and volumes needed to make PCR master mix. 2. For TWO PCR reactions, you need to prepare PCR master mix for 2.5 reactions (on ice). Pipette the solutions 1, 2, 3, 4 into a sterile microcentrifuge tube. What is the reason for preparing volumes for 2.5 reactions of PCR master mix solutions? To save time and minimize error in the repeating...
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...Gianna Crowe Bio Lab 117 October 16th, 2014 Most enzymes are proteins that speed up reactions and are characterized as catalysts. Enzymes work in such a way that when the right chemicals of a molecule are present for the enzyme, it will fully fit the shape. The part of the particular shape is called the active site of the enzyme, since this is where the reaction occurs. The molecule that the enzyme works on is called the substrate. An enzyme reaction includes a substrate (substance) that is converted to another product. The unique shape of the active site of the enzyme allows it to bind with only certain kinds of molecules, which is the substrate of the enzyme (Strobl 2014). A substrate binds to the active site of the enzyme to form a enzyme-substrate complex for a very short time, this then becomes part of a new formation and a new product of a specific reaction is formed then released freeing the active site, allowing the enzyme to repeatedly bind another substrate. Enzymes are produced by all living things, and are a necessity to life. They are responsible for constructing, synthesizing, carrying, dispensing, delivering, and eliminating the many chemicals associated in living organisms (Colpa 2014). An example for how enzymes work in living organisms would be the process of food digestion, enzymes work to break down food and speed up the digestion process. Factors that affect enzyme activity deal with environmental conditions, which are temperature, salt concentration,...
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...Dr. Hjorth-Gustin Chemistry 201 Lab November 8th, 2010 Synthesis and Analysis of Iron(III) Oxalate Complex Discussion This experiment initially involved the synthesis of an iron (III) oxalate complex with the general formula Kw[Fex(C2O4)y] zH2O. The variables x, y, and z were determined through the duration of the entire experiment. Part 1 involves the synthesis of an iron (III) oxalate complex. The iron is first presented in its Fe2+ form, so it must first be oxidized to Fe3+ before the oxalate ion will readily bind to it. Hydrogen peroxide is the oxidant of choice: 2Fe2+ (aq) + H2O2 (l) + 2H+ (aq) ---> 2Fe3+ (aq) + 2H2O (l), in acidic solution. The oxalate ion is then free to coordinate to the Fe3+ ion, forming a complex of Fe(C2O4). The oxalate ion is the conjugate base of the weak oxalic acid, H2C2O4. In the synthesis of the iron (III) oxalate complex, 0.8668g of the final lime-green crystals were obtained. The average percent of C2O4 was 59.00% and the theoretical yield was 53.74%. With this, the percent error came out to 9.79%. The percentage of Fe(III) in the green crystal obtained was 14.5%. Theoretically, it should have been around 10%. This lack of accuracy was quite difficult to recognize considering the calculations were approved by the professor but may have been due to incorrectly preparing the buffer. Apart from the usual human-mediated errors in the measuring and distribution of chemicals and in the readings of instrumental...
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...Nursing Lab Values Cheat Sheet permalink ________________________________________ Lab Values: Cheat Sheet Red Blood Cells (RBC): - Normal: male = 4.6- 6.2 female = 4.2- 5.2 - Actual count of red corpuscles Hemoglobin: - Normal: male = 14-18 g/dl female = 12-16 g/dl - A direct measure of oxygen carrying capacity of the blood Hematocrit : - Normal: males = 39- 49% female = 35- 45% - = the percentage of blood that is composed of erythrocytes Mean Cell Volume (MCV): - Normal: male = 80- 96 female = 82- 98 - Mean Cell Hemoglobin (MCH): - Normal: 27- 33 - = % volume of hemoglobin per RBC * Increase: indicates folate deficiency * Decrease: indicates iron deficiency Mean Cell Hemoglobin Concentration): - Normal: 31- 35 Reticulocyte Count: - Normal: 0.5-2.5% of RBC - An indirect measure of RBC production Red Blood Cell Distribution Width (RDW): - Normal: 11-16% - Indicates variation in red cell volume * Increase: indicates iron deficiency anemia or mixed anemia - Note: increase in RDW occurs earlier than decrease in MCV therefore RDW is used for early detection of iron deficiency anemia Platelet Count: - Normal: 140,000 - 440,000 * Low: worry patient will bleed * High: not clinically significant White Blood Cell (WBC): - Normal: 3.4 – 10 * Increase: occur during infections and physiologic stress * Decreases: marrow suppression and chemotherapy Sodium (Na): - Normal: 136- 145 - Major contributory to cell osmolality...
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...Introduction The profound importance for microorganisms to operate at a maximum efficiency has lead to adaptations allowing for groups of processes to be functional when resources are available, while on the contrary remaining “dormant” when not in need. This has been accomplished at the molecular level by configuring clusters of genes together on the genome into operons that elicit a processive response in the presence of a specific metabolite. The Lac operon is responsible for the cleaving of the disaccharide lactose into two products. A myriad of components control the expression of the Lac operon when two conditions are met. First, the substrate, lactose, must be present. Second, no better substrate for example, glucose, is present (2). The three structural genes in the Lac operon are lacZ, lacY, and lacA. The gene lacZ encodes the tetramer, ß-galactosidase, which is responsible for hydrolyzing the ß-1,4 glycosidic linkage between galactose and glucose in lactose. The transport of lactose into the cell via the enzyme lactose permease is encoded by the gene lacY. The lacA gene encodes the enzyme, galactoside transacetylase, a trimer that transfers an acetyl group from acetyl-CoA to galactosides. Activation of these genes is dependent on the activity of a promoter and three operators based on the nutritional and environmental conditions available to the cell. The lac operon is a negatively controlled inducible operon that utilizes the product of the regulator gene lacI, to...
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...reference to the human body. (LECT & LAB) Describe each of the following levels of organization of the human body: chemical, cellular, tissue, system, organism. (LECT & LAB) Identify the principal systems of the body. (LECT & LAB) Describe the standard anatomical position of the human body. (LECT & LAB) Compare common anatomical terms used to describe the various regions of the human body. (LECT & LAB) List by name and location the principal body cavities. (LECT & LAB) Define homeostasis and explain the effects of the lack of homeostasis on the body's function. (LECT & LAB) Describe the chemical level of organization of the human body. Describe the interrelationship of matter, elements, and atoms. (LECT) Identify by name and symbol the principal elements of the human body. (LECT) Diagram and label the structure of a typical atom. (LECT) Describe the function of electrons located in incomplete outer energy levels. (LECT) Define the terms isotope and radioisotope and give their functions. (LECT) Describe the three types of chemical bonding (ionic, covalent, hydrogen) and give an example of each. (LECT) Describe what happens during a chemical reaction. Give three types of chemical reactions. (LECT) Interpret the information given in chemical notations. (LECT) Define ion, oxidation, and reduction. (LECT) Distinguish between organic and inorganic molecules. (LECT & LAB) Define solution, solute, and solvent. (LECT & LAB) Define...
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