From a small culture, you have purified the DNA of a recombinant plasmid. You add 275 μL of elution buffer to resuspend the DNA. You pipet 1 μL of the resuspended DNA with 229 μL of distilled water for a total of 230 μL. You measure the absorbance of the diluted sample at 260 nm and 280 nm in the spectrophotometer and obtain the following readings: A260 = 0.622; A280 = 0.086. 1. What is the DNA concentration of the 275 μL plasmid miniprep in micrograms per microliter? Answer to three decimal places: 2. How much total DNA in micrograms was purified by the plasmid prep procedure? Answer to one decimal place.
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Step 1: Calculate the concentration of the DNA in the diluted sample using the absorbance readings at 260 nm and 280 nm. Show more…
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From a small culture, you have purified the DNA of a recombinant plasmid. You add 275 mL of elution buffer to resuspend the DNA. You pipette 1 mL of the resuspended DNA with 229 mL of distilled water for a total of 230 mL. You measure the absorbance of the diluted sample at 260 nm and 280 nm in the spectrophotometer and obtain the following readings: A260= 0.622; A280= 0.086. 1. What is the DNA concentration of the 275 mL plasmid miniprep in micrograms per microliter? 2. How much total DNA in micrograms was purified by the plasmid prep procedure? 3. What is the A260/A280 ratio of the purified DNA? 4. A DNA solution has an A260 value of 0.749. Using Beer's Law, what is the DNA concentration in micrograms of DNA/mL? 5. A solution of DNA has an A260 of 0.208. What is its millimolar concentration?
Jenny W.
You have isolated plasmid vector DNA and suspended it in 400 µL. To determine the concentration, you take 3 µL of the DNA sample and dilute it with 147 µL of dH2O. You then take a reading of the DNA on the spectrophotometer, and it gives you an OD reading of 0.16. What was the concentration of your original DNA sample? What is the total DNA concentration present in 200 µL? What is the concentration of DNA per µL? (1 OD DNA is 50 µg/mL)
The concentration of DNA in a purified sample can be measured by measuring light absorbance at 260nm (A260nm). An A260nm value of 1 corresponds to a double-stranded DNA concentration of 50 ng/μl. Plasmid DNA isolated from bacteria often needs to be diluted to obtain an accurate measurement. After resuspending 40 μL of a purified DNA sample in 760 μL of water, an absorbance of 0.27 was recorded using a spectrophotometer. What is the concentration (in ng/μL) of the original DNA sample purified?
Md.Daniyal A.
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