Biology Forums - Study Force

Hello, i need some help on part b of this question I dont know how to approach it.

The following scenario will be used to answer the following questions.

You are working in a lab and are asked to make a 2% agarose gel in a gel electrophoresis experiment. The percentage of agarose gel is a weight/volume measurement, which means that for this gel, 2% of the total volume (in millimeters) will be agarose (in grams). For the size gel that you will be pouring, the graduate student tells you to make a 120 ml total volume. The buffer you will use is called TAE. A graduate student shows you the stock of TAE, and it is marked 10 x. This means that the stock is ten times more concentrated than the concentration needed in the gel. H2O will make up the remainder of the 120 ml total volume. You will need to calculate how much agarose, TAE stock and H2O that you will need in order to make your dilution.

a)How many grams of agarose will you need to use?
2% of 120 mL = 2.4 g

b)How many milliters of the 10 x TAE stick will you add to the flask containing your agarose?

Thanks!

You have a 10X stock solution of TAE so you have to use 1/10 the final desired volume. If your final volume is to be 120 ml of 1X TAE you use 12 ml of 10X TAE. The whole solution will be made by adding 2.4 gm of agarose to 12 ml of 10X TAE and 108 ml of water.

I never do, but I suppose to be anal about it you could take the volume of agarose into account. I'd be willing to bet that 97.29% of us don't bother and treat the agarose as if it had no volume. I don't know the density of solid agarose or even how to account for the volume of hydrated agarose.