Question

please hlep me answer those three questions asap.

Please ignore question 7.

Question 7 Working with buffers You need 100 ml of 120 mM phosphate buffer and you have two stock solutions from which you can make the buffer; 0.6 M NaH2PO4 (the acid form) and 0.6 M Na2HP04 (the base form). You need to add 3 times more of the base form than the acid form to achieve the desired pH. How will you make this solution? Question 8 Working with liquids Blood alcohol measurements > 0.05% (v/v) result in severe traffic fines and licence suspension. This measurement is carried out using an enzyme assay, alcohol dehydrogenase and the values nitially obtained are in mM. You have obtained a final [ethanol of 10.3 mM (i) What is the ethanol concentration in % (v/v)? The density of ethanol is 0.79 gmL and the molecular weight 46 [ethanol] in mM. Question 4 Using molecular weight You need a 10 mM solution of caffeine (mol. wt. 200) for an experiment. The caffeine has been purchased in 100 mg batches. What volume would you add to make up one 100 mg batch to 10 mM? Question 5 Using stock solutions in a protocol: from volume to final concentration A DNA ligation reaction is carried out in a 25 μL reaction mix. This is a reaction carried out in cloning. You are going to do a number of these reactions so you decide to make up a larger volume of the reaction mixture, called a master mix. This saves on multiple repetitive pipetting and reduces errors. You have been given a protocol to make up 1 mL of this ligation master mix and it states that you must add 2 μしof a 100 mM ATP. What is the final concentration of ATP in the ligation reaction? You need to do 30 ligation reactions. Do you have enough reaction mixture with the 1 mL? Question 6 Using stock solutions to make up a solution: from final concentration to volume Later this semester you will be separating DNA fragments by gel electrophoresis. To make an agarose gel, you need to melt a preparation of 0.8% (w/v) agarose in a buffer called TBE (see page 2..19) that is composed of 89 mM Tris CI, 89 mM Na borate and 2 mM EDTA. You have the following stock solutions; M Tris C, 1 M Na borate, 0.2 M EDTA and agarose powder. How would you make up a 100 ml agarose gel?

Answer 1

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