NEET2019ZoologyBiotechnology - Principles and ProcessesActual
DNA's precipitation out of a mixture of biomolecules can be achieved by treatment with:
Options
- AIsopropanol
- BChilled ethanol
- CMethanol at room temperature
- DChilled chloroform
Correct answer
B. Chilled ethanol
Step-by-step solution
DNA is highly polarised due to phosphate backbone. This makes it highly soluble in water. Generally, 0.3 M Sodium Acetate is used which neutralizes the negative charge on the PO3- groups on the nucleic acids, making the molecule far less hydrophilic, and therefore much less soluble in water. Then, three volumes of (at least) 95% ethanol is added that removes the hydration shell of H2O molecules around the phosphate.