DILUTIONS AND STANDARDS Many of the laboratory procedures involve the use of dilutions. It is important to understand the concept of dilutions‚ since they are a hand tool used throughout all areas of the clinical laboratory. These dilutions have to be considered as they make a quantitative difference in what is going on. First‚ there are several terms used in expressing dilution: 1. "Dilution: - Dilutions are expressed as the ratio of the quantity of a desired solute (serum‚ urine‚ chemical solution
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Serial Dilution Activity Many applications require the determination of microbial numbers. Those applications can be either clinical or in a research setting. Clinical applications include determination of antibiotic efficacy and as well as therapy. Research applications include determination of the effectiveness of antimicrobial chemicals‚ radiation‚ etc. The viable count is most common or standard method used to quantitate bacteria. With this method only microbes that are alive and able to reproduce
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1) Why serial dilutions are preferred to one large dilution in lab experiments? Answer: Serial dilution is the technique of performing repeated dilutions on the same chemical in order to change its concentration. The diluted solution from a serial dilution can be used to calculate the concentration of the actual solution. In experimental work‚ often we need to obtain a range of concentrations for a specific compound. Thus‚ instead of preparing one large dilution‚ if we take a concentrated sample
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Professor Rotibi ABSTRACT: Accurate evaluation of bacterial colonization as a predictive index for alfalfa sprouts has relied on a quantitative culture technique that provides exact colony counts per gram of tissue by culture of five serial dilutions of the alfalfa water. In this study 1 package of alfalfa sprouts were cultured by a semi-quantitative technique that enumerated the number of gram-negative enteric organism in 1 ml of alfalfa water. Exact colony counts from the experiment were
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1. Introduction: The goal of this lab was to demonstrate the microbiology technique of serial dilutions and how they can effectively be used in experiments. E. coli cells were exposed to UV light for various amounts of time in order to asses the effect on growth and thereby mutations since this cell was modified to not have photolyse no uvr genes for DNA repair and thus can only use the SOS response. Each group then diluted the cells accordingly based on their UV exposure time and counted the cells
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OD was surveyed at 595. The UK protein in µg was assessed by taken the equation y=0.0259x+.0511 (Fig. 1) and solving for x where y is the OD. Calculation of UK Samp ID | µl of UK Assayed | OD @ 595 | µg UK protein | µg UK/µl(Diluted Sample) | Dilution Factor | UK Conc in µg/µl | 1:50 | 10 | .215 | 6.33 | .633 | 50 | 31.65 | 1:100 | 10 | .092 | 1.58 | .158 | 100 | 15.80 | 1:250 | 10 | .075 | 0.92 | .092 | 250 | 23.00 |
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The latter involves serial dilution and spread plating of bacteria on agar plates. Materials required per pair • One 10 ml liquid culture of Escherichia coli BL21 (see prior preparation) • A sample of Yakult (approximately 5 ml) • Marker pens to label plates & bottles • Sterile plastic loops for streaking bacteria (up to 20 per pair) • Sterile plastic spreaders for spreading bacteria (4 per pair) • Sterile universals/bijoux bottles (8 per pair) for serial dilutions • 10 ml sterile phosphate
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growth of yeast is measured by using spectrophotometer and hemocytometer.We learnt how specthophotometer and hemocytometer use and also we learnt qualifications of hemocytometer and spectrophotometer.Serial dilution was used for this experiment and it was very important.Because of the serial dilution‚we measured the number of yeast cells. The graph of growth curve was drawn and bacterial life cycle was understood with the graph.The purpose of the experiment was to calculate and draw bacterial growth
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spectrum to determine the concentration of light absorbing molecules in a solution. (p.59) In this particular lab‚ our mission was to determine the protein concentration and the standard curve of the unknown sample of BSA. This‚ by preparing five dilutions of the unknown solution of BSA together with other known concentrations‚ and then experimenting by observing how the concentrations were passed through the spectrophotometer. The outcome resolved in the absorption levels being decreased‚ and this
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experiment allowed the students to perform the plate count technique by serial dilution and two common methods‚ spread plate and pour plate to determine the colony forming unit (CFU) of yeasts A ten-fold dilution is used in this experiment‚ the sample is diluted until it reached the 10-9 dilution. Plating for spread plate started from 10-5‚ 10-6‚ 10-7 and 10-8 dilution while for pour plate‚ it started from 10-6‚ 10-7‚ 10-8 and 10-9 dilution. Having incubated inverted at room temperature (25oC) for 2 days
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