Kathleen Kramas
Cells and Heredity Lab
Tuesday 2:00-4:50
22 OCTOBER 2012
Membrane Permeability Decreases as Molecular Size Increases
Introduction:
Red blood cells are vital to organisms functioning properly. They are microscopic cells that carry oxygen from the lungs to all the tissues throughout the body. Upon transporting oxygen, red blood cells also exports waste, such as carbon dioxide, to the lungs where it can be expelled. Red blood cells are made up of hemoglobin which is surrounded by a cell membrane (Barrilleaux 2012). Organisms also have white blood cells, also referred to as leukocytes, which combat foreign antibodies in the immune system. White blood cells are complex in structure, and in contrast to red blood cells, have a
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We pipetted 1.2 mL of .3M glycerol into a cuvette and blanked the machine. We then mixed 3 ml of .3M glycerol and 10 ul of whole blood [1] in a test tube, covered it with parafilm and then inverted the tube to mix the solution adequately. We then pipetted 1.2 mL of the blood/glycerol solution into a new cuvette, put it in the spectrophotometer and recorded the absorbance for a time of ‘zero’. We then repeated these steps with .15M NaCl. We blanked 1.2 mL of a .15M solution, and then mixed 3mL of the .15M solution and 10 ul of horse blood in a test tube. We covered the test tube with parafilm and inverted the mixture, we then pipetted 1.2 mL of the mixture out and into a new cuvette. We measured the absorbance for a time of ‘zero’. We then simultaneously measured the absorbance of the glycerol/blood mixture and the NaCl/blood mixture every minute for 30 minutes. Basic Contrast Microscopy: We cleaned two glass slides with alcohol and put them aside. We then combined 1 mL of .15M NaCl and 10ul of whole horse blood in a microcentrifuge and immediately transferred 10 mL of the mixture to the clean glass slide, added a cover slip, recorded the start time and watched the cells under 400x bright 4field microscopy and recorded what we observed. We then switched to 400x phase contrast microscopy and also recorded what we saw
From this graph and chart we can see that the higher the concentration the higher the absorbance, all the different concentrations were tested at the same wavelength (625nm). Also we can determine our unknown substances concentration by using the absorbance we got for it. The red dot on the graph followed by the line towards the horizontal axis indicates that the concentration of fast green was 34% or 5.1x10-3.
3ml of sample was taken first flask at 4 minutes and added to the appropriate tube of sodium hydroxide, from the second flask at 4.5 minute and so on, each flask was sampled at 30 second intervals. The sampling was then repeated starting at 8,12,16 minutes. The final sample from the last flask was taken at 18.5 minutes. Once the sampling was completed, measurements of absorbance were obtained for solution in each tube at 405 nm.
10 microliters of the sample is then added and the assay absorption is measured at 340nm. If absorbance was above 1.5, samples were diluted.
With all solutes set at a concentration of 5.00 mg/ml and the MWCO set at 20, filtration stopped at 60 minutes, and the projected completion was 100 minutes. The residue analysis indicated all solutes present in the dialysis membrane. The filtrate concentrations for all solutes was 0.00 mg/ml. With all solutes set at a concentration of 5.00 mg/m and the MWCO set at 50, the filtration completed in 40 minutes. The residue analysis indicated all solutes present in the dialysis membrane. The filtrate concentration for NaCl was 4.81 mg/ml, and 0.00 mg/ml for all remaining
The same solution of 0.5 ml BSA was then added from test tube 1 to the test tube 2 after being properly mixed, and from test tube 2 the solution was being added to test tube 3, and so forth all the way up to test tube 5, with the same exact procedure. From the last tube, we then disposed the 0.5 ml solution. After above procedures, we now labeled another test tube “blank”; 0.5 ml blank distilled water was purred into the tube with the serial dilution of 1:10. We also had a tube C labeled “unknown” with the same 0.5 ml of solution. And after adding 5ml of Coomassie Blue to each tube (1-5) and to the blank, the result of absorbance was read at 595 nm.
The isosbestic point of the acid (pH6) and basic forms (pH10) of para Nitrophenol (PNP) was expected at 350nm. As you can see in figure 2, the graph shows the intersection of 2 curves at ~350nm, which is matched with the literature value. Also, the pKa of PNP was expected 7.15 at room temperature. Refer to figure 3, the pKa is estimated to be 7.15-7.2, which very close to the literature value. In addition, the lab was succeeded in illustrating the use of a spectrophotometry to analyze concentrations of chemical substance. The absorbances of 2 unknowns were felt on the standard curve as the expectation (refer to table 4). The minimum absorbance of the known standards was 0.193 and the maximum is 1.830. The absorbance of the unknown
Time) because it had a correlation closest to 1. All three orders were graphed and a linear regression was used to see which graphed order was closest to 1. The order was determined by comparing the concentration and time to the mathematical predictions made using the integrated rate laws. Analyzing each graph and finding each correlation helped determine which graph was closest to 1. The more concentrated a solution is, the higher the absorbance of that solution. This is due to Beer’s Law. The law measures the absorbance of a solution by determining how much light passes through a solution. As the concentration of a solution increases, fewer wavelengths of light are able to pass through the concentrated solution. The absorbance at 60 seconds was 0.573 (Figure 1: Table1). To calculate the concentration (molarity), the Beer’s Law equation was used, Abs = slope(m)+b. Plugging in what is known into the Beer’s Law equation resulted in 0.573 = 3.172e+004 + 0, where the concentration is determined by M = 0.573-0/ 3.172e+004. So, the concentration at 60 seconds using the equation (M = 0.573-0 / 3.172e+004) was 1.824e-5 M. The 1st order graph resulted in k=0.006152 (Figure 1: Graph 1). Other groups also resulted in their decolorization of CV to be the 1st rate
The Beers Law calibration experiment used many concentrations of crystal violet solutions. Each of these solutions were test and analyzed in order to determine the absorbance of each concentration The results were than graphed and produced a slope of 1.00E05 with an intercept of -2.21E-02.
Make sure to use the same type of cuvette to keep the width consistent and to prevent any experimental error from arising. Obtain 5 of the same type of cuvettes and pre-rinse them thoroughly. Label them numbers one through five in increasing molarity. Then, fill each of the cuvettes with one of the five solutions you created back in Part A. We will first examine the solution that exhibits the highest concentration or molarity. Make sure to wipe the outside of the cuvette with a Kimwipe before placing into the SpectroVis Plus device. Observe the graph that is generated and make sure to take note where the maximum absorbance takes place.
The values of color absorbance are effective because color absorbance has a linear relationship with concentration values, which in turn, allows us to easily find concentration values for many solutions. Beer’s law describes this phenomenon since the absorbance is directly proportional to concentration. We observed that as the color absorbance increased, the concentration of the FeSCN2+ complex ion increased. This is because as the FeSCN2+ concentration increases, the blood-red color becomes darker due to more presence of the blood-red FeSCN2+ ion. Therefore, the color absorbance increases because there is more blue color absorbed by the darker red color. We then graphed the absorbance and concentration values and created a line of best fit. Using the line of best fit, we were able to predict the equilibrium concentrations of the FeSCN2+ solutions and find the change required to reach equilibrium. Since we already knew the initial concentration of FeSCN2+ and since we already found the equilibrium concentration of FeSCN2+, we can calculate the change in equilibrium. Using this data, we were able to calculate the equilibrium concentration of all of the species in this lab, since we already knew the change from the initial concentration to the equilibrium change. Q is less than K because there was no initial concentration of FeSCN2+, but after the system reached
The absorbance is measured using a Plate reader and a Standard curve is generated. Also, the different types of pipetting techniques are assessed in this Assay.
Incorporation of assay controls included setting up a spectrophotomer and running the chart recorder with a full-scale deflection before the start of the assay. The set recorder had a corresponding value of 1 for the change in the absorbance. Therefore, prior testing was done to observe whether a change occurred in the readings. This helped to indicate that the results were valid, as they could have been affected by a fault during the setting up of the spectrophotometer. On the other hand this was considered as one of the controls for the experiment. Nevertheless, a new cuvette had to be used for each assay.
Haemoglobin is a protein molecule found in red blood cells (RBC). Its role in the body is to transport oxygen from the lungs to the body 's tissues and then returns carbon dioxide from the tissues back to the lungs. The transportation of oxygen is only possible when haemoglobin (Hb) within the RBC binds to oxygen. (Martini & Nath, 2006)
After the 30 minutes, the color was observed and recorded on the data sheet. The dialysis tubing was removed from the beaker and a small slice was made, we then used a glucose indicator strip to test for the presence of glucose, along with the solution in the beaker. The results were then recorded in table 1on the data sheet.
Red blood cells (also referred to as erythrocytes) are the most common type of blood cell and the vertebrateorganism's principal means of delivering oxygen (O2) to the body tissues via the blood flow through thecirculatory system. They take up oxygen in the lungs or gills and release it while squeezing through the body'scapillaries.