see the attached files

DNA Purity & Concentration

Given the following spectrophotometric readings, calculate the purity and concentration of the following samples.

To complete the table below, follow the directions in the steps outlined below (# 1-9).

Refer to Step: # 2 #3 #6 #7 #8 #9

5ul of sample DNA is diluted with 995ul of HOH. The absorbances are read on a spectrophotometer at 260nm and 280nm.

1. What is the dilution for the samples? Dilution of Samples = ________________.

Purity

1. Calculate the Purity Ratio for the above samples. Record in table above.

2. Check the purity of each sample with the desired range and fill in the corresponding column for the Purity Ratio: OK /Increased/Decreased.

Desired Range 260/280 = ________________ Use the range found in the textbook

1. List the Samples that are not considered pure below, and the source of the contamination.

This information is found in your textbook.

Sample Contaminated with?

1. For the contaminated samples above. Describe what can be done to further purify the samples.

Quantity of DNA in Each Sample

1. Using the absorbance readings obtained. Calculate the concentration of DNA in each sample in ug/ml. Record the values in the table.

Refer to your textbook for the calculation formula:

DNA at 260nm: 1.0 Abs = 50ug/ml Also, don’t forget the Dilution Factor.

1. Convert ug/ml to ug/ul. Record values in the table.

Determine Sample & Diluent Amount needed to Load the Gel Lanes.

1. Given that the same amount of DNA needs to be loaded onto each lane in the gel. (10 ug / lane) How many ul of each of the samples is needed? Record amounts in the chart.

1. Given that the Total volume of sample needed is 20ul. How much diluent needs to be added to each sample to have a 10ug concentration? Record amounts in the table.