At physiological pH DNA is ?

Ans. is 'd' i.e., All of the above DNA is amphipathic Amphipathic molecule is one which contains both polar (hydrophilic) and nonpolar (hydrophobic) regions in its structure, i.e. the pa of molecule is water soluble and pa is water insoluble. In DNA helix Hydrophilic (polar) deoxyribose-phosphate of each chain is on outside of molecule. Hydrophobic (nonpolar) bases are stacked in. Thus DNA is regarded as amphipathic in nature. DNA is negatively charged and acidic Phosphate group lies on outside of molecule of DNA. Each phosphate group has a negative charge at physiological pH, making DNA a negatively charge (anion) at physilogical pH. "Histones are strongly cationic and can bind non-specifically to strongly aniomic DNA" Harper "At physiological pH DNA is negatively charged, and is associated with positively charged (basic) histones" Ronald Hofmann. o Anionic molecules are acidic in nature.