Question

I need to make 1.25% agarose gel to run a 33uL sample of digested dna. The gel box is 10cm x 25cm. the comb teeth is 0.5cmx0.15cm. Need amount of TAE buffer & amount of agar.

Answer 1

This is quite a real world question - I guess that the teeth of the comb are 15mm by 0.5mm so the volume of a well in a 1cm thick gel would be 10mm x 0.5mm x 15mm. I hope this helps: 1000cm3 is equivalent to one litre, so 1cm3 is equivalent to 1ml and 1mm3 is equivalent to 1ul. So your 33ul sample would fit nicely into a well half as deep as the one I mentioned earlier.

To get your answer for how much agarose multiply the depth (maybe 0.5cm) by the width and the length, both in cm. Then multiply by 1.25g per 100ml. The volume of the gel is the amount of TAE buffer. Get back to me if you have any problems.

Answer 2

the teeth of the comb is 0.5cm x 0.15cm to get the depth shouldn't i just be able to use the formula: 0.5cm x 0.15cm x D = V(33ul)

Answer 3

You could use the formula but please remember the units are all important. Once you have the depth then use the rest of the explanation I gave you for the rest of the question. Best wishes,

Answer 4

thanks so much for all your help!