Practice question

Organic extraction partitioning of DNA depends on physicochemical properties like solubility and polarity rather than size alone. Nucleic acids are highly hydrophilic polyanions due to sugar-phosphate backbone, favoring aqueous phase. Proteins, especially after phenol denaturation, expose hydrophobic residues and partition into organic phase or interphase. Phenol-chloroform mixture creates immiscible layers where hydrophilic molecules dissolve in water and hydrophobic in organic. Temperature, pH of phenol influences RNA vs DNA partitioning, and size influences precipitation, but phase preference is fundamentally determined by relative solubility differences.