Question

1. preparing your samples. normally your dna agarose samples include: 1. dna and 2. loading dye. sometimes you will also add water. loading dye has multiple purposes: 1. it will help your samples sink to the bottom of the well and 2. it will help you watch the migration of your dna samples. you will be given a mock dna sample (2.5 μg/μl) and 6x loading dye. you will need to determine the appropriate total volume you will need to load with still being able to fit it in your well. common volumes are ~15 - 20 μl. prelab question - 19 (1 pt). if you want to load a total of 10 μg of dna list the volume of your dna solution you need. prelab question - 20 (1 pt). determine the total volume you will load on your gel. prelab question - 21 (1 pt). determine the volume of 6x loading dye. determine the volume of water you will need to add.

Explanation:

Pre - lab Question - 19

Step1: Use the concentration formula

The concentration formula is \(C=\frac{m}{V}\), where \(C\) is the concentration (\(C = 2.5\ \mu g/\mu l\)), \(m\) is the mass (\(m=10\ \mu g\)), and \(V\) is the volume. Rearranging for \(V\), we get \(V=\frac{m}{C}\).

Step2: Substitute the values

Substitute \(m = 10\ \mu g\) and \(C=2.5\ \mu g/\mu l\) into the formula: \(V=\frac{10\ \mu g}{2.5\ \mu g/\mu l}=4\ \mu l\).

Pre - lab Question - 20

Assuming a common volume (since the problem doesn't give more constraints other than fitting in the well and common volumes are \(15 - 20\ \mu l\)), we can choose \(15\ \mu l\) (a common value within the given range).

Pre - lab Question - 21

Step1: Use the dilution formula for loading dye

For a \(6X\) loading dye, if the final volume \(V_{total}=15\ \mu l\), and let the volume of loading dye be \(V_{dye}\). In a \(6X\) loading dye, the fraction of loading dye in the final solution is \(\frac{1}{6}\) (because \(C_1V_1 = C_2V_2\), and if \(C_1 = 6X\), \(C_2 = 1X\) (the working concentration), then \(V_1=\frac{V_2}{6}\)).

Step2: Calculate the volume of loading dye

\(V_{dye}=\frac{15\ \mu l}{6}=2.5\ \mu l\)

Step3: Calculate the volume of water

The volume of DNA is \(V_{DNA}=4\ \mu l\), the volume of loading dye \(V_{dye}=2.5\ \mu l\), and the total volume \(V_{total}=15\ \mu l\). Using \(V_{total}=V_{DNA}+V_{dye}+V_{water}\), we can solve for \(V_{water}\).
\(V_{water}=V_{total}-V_{DNA}-V_{dye}\)
\(V_{water}=15\ \mu l - 4\ \mu l-2.5\ \mu l = 8.5\ \mu l\)

Answer:

• Pre - lab Question - 19: \(4\ \mu l\)
• Pre - lab Question - 20: \(15\ \mu l\)
• Pre - lab Question - 21: Volume of \(6X\) loading dye is \(2.5\ \mu l\), volume of water is \(8.5\ \mu l\)