Final answer:
Nucleic acids are acidic due to their phosphate groups which can release a proton ionized at physiological pH levels, making them essential for cellular functions.
Step-by-step explanation:
The most correct statement regarding nucleic acids is that they are acidic compounds first discovered in the cell nucleus and later found in the cytoplasm, mitochondria, and chloroplasts. Nucleic acids are high molecular weight, nitrogenous organic compounds essential for the storage, transmission, and control of cellular activities. A nucleic acid is defined as a polynucleotide, which is a polymer chain consisting of thousands of nucleotide units. Each nucleotide is made up of a nucleoside and phosphoric acid.
An acid is a substance that releases hydrogen ions (H+) in a solution. A positively charged hydrogen ion is simply a proton, which is prone to participate in chemical reactions. Nucleic acids release a proton (H+) from their phosphate group that is ionized at physiological pH, contributing to their acidic properties. Strong acids ionize completely in solution, while weak acids do not ionize fully, with some hydrogen ions remaining bonded within a compound.
In essence, nucleic acids are considered acids because each phosphate group in the nucleotide has one acidic hydrogen atom that gets ionized at physiological pH levels, making these compounds acids in the biological context.