I need help with question 2 It is often necessary to make your own solutions to

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I need help with question 2

It is often necessary to make your own solutions to use during experimentation in the laboratory. Solutions used during experimentation are made from either liquid stock solutions of known concentrations or solid chemicals that require weighing and dissolving in either buffer or water. In both instances, the stock solution or dry chemical is the solute and the buffer or water becomes the solvent In the case of liquid stock solutions, the concentration of the solution needed for your experiment is often less than that of the stock solution, so dilution using buffer or water is necessary. In this case, it is necessary to do some simple calculations in order to determine what volume of stock solution (solute) and what volume of buffer or water (solvent) to use to make your final solution. You will use the following equation to do this C, Concentration of stock solution (solute) used to make the final solution v, volume of the stock solution (solute) that you will add to make the final solution C2 New concentration of the stock solution in the final solution V Total volume of the final solution after all of the solute(s) and solvent are added. All the information required to solve for any unknown in the above equation can be found using the reading/experimental protocol and by completing a MIXING TABLE Creating a MIXING TABLE gets you organized to prepare solutions of desired concentration with accuracy. An example mixing table for preparing one solution containing 3 different solutes is shown below Table I. Sample Mixing Table 1 0% H2O2 (n!) | 100)% Turnip Extract (ml) | 3 08 m ml Guaacol (ml) | Buffer pH 5 (ml) Tube 2 Vi The volumes (ml) of stock solutions: H202, Turnip Extract and Guaiacol listed in the mixing table are the Vi for each of those solutes (note that the pH 5 buffer is the solvent for the solution). When you are filling in your own mixing table, you are solving for Vi. G The concentrations of the stock solutions are in the column headings of this mixing table ( 1.0%, 100%, 308 mg/ml). They may also be given in the reading or protocol for an experiment. V2 The final volume of the solution. If you add up the volume of each of the solutes plus the solvent, you get the V: for the final solution For example, the V: for Tube 1 (above) is 8.0 ml. C2 -Not given in this example, but with all of the above information, you can calculate C. Ifthe C: that you need for an experiment is known (as it usually is), it will be given to you and you will be solving for Vi. In other words, you would have to determine how much of a stock solution you need to prepare a working' or final' solution. Molecular Biology requires working with very small volumes of liquid (microliters, l) and using equipment capable of measuring such small volumes. You will use micropipettors in lab to measure volumes of liquid less t 10 . You will need to recall the following conversions: 1000 L 1.0 ml 1000 Hg 1.0 mg

Explanation / Answer

2) Final concentration of lambda DNA required is 0.0125 ug/ul

Stock concentration is 0.05 ug/ul

Reaction volume is 10 ul

So, by using the formula C1V1= C2 V2

0.05 ug/ul * V1 = 0.0125 ug/ul * 10 ul

V1 = 2.5 ul So, 2.5 ul stock lamba concentration is used in the reaction.

Stock restriction enzyme buffer is 5X. Needed reaction final concentration is 1 X

so 5 X * V1 = 1X * 10 ul

So, V1 = 2 ul, So 2 ul of 5X restriction buffer is used in the reaction

Reaction mixture components for negative control

Components : Volume in ul

Lambda enzyme(stock) : 2.5 ul

5X restriction buffer : 2.0 ul

Sterile deionised water : 5.5 ul

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