Question

question 10 1.5 pts a biol 1100 student is extracting dna from her cheek cells. in her cheek swab, she obtained two million cells. each cell contains 3.6 nanograms of dna. she isolates this dna using detergent and alcohol. the isolation procedure results in a loss of 30% of the dna. after her dna has been isolated, she resuspends it in a final volume of 1.5ml of water. what is the final concentration of her isolated dna? express your answer as a decimal in ug/ul. be sure to solve this problem so that you are able to show your work.

Explanation:

Step1: Calculate total initial DNA

Total initial DNA = Number of cells × DNA per cell
$2 \times 10^6 \text{ cells} \times 3.6 \text{ ng/cell} = 7.2 \times 10^6 \text{ ng}$

Step2: Account for 30% DNA loss

Remaining DNA = Initial DNA × (1 - 0.30)
$7.2 \times 10^6 \text{ ng} \times 0.70 = 5.04 \times 10^6 \text{ ng}$

Step3: Convert ng to μg

$1 \text{ μg} = 1000 \text{ ng}$, so:
$5.04 \times 10^6 \text{ ng} \times \frac{1 \text{ μg}}{1000 \text{ ng}} = 5040 \text{ μg}$

Step4: Convert mL to μL

$1 \text{ mL} = 1000 \text{ μL}$, so:
$1.5 \text{ mL} \times \frac{1000 \text{ μL}}{1 \text{ mL}} = 1500 \text{ μL}$

Step5: Calculate final concentration

Concentration = $\frac{\text{Total isolated DNA}}{\text{Final volume}}$
$\frac{5040 \text{ μg}}{1500 \text{ μL}} = 3.36 \text{ μg/μL}$

Answer:

3.36