Nucleotides and Nucleic Acids (5D) Practice Test

In a structural analysis of a 16-nt single-stranded nucleic acid isolated from a viral particle, enzymatic digestion showed the polymer was resistant to RNase A but was degraded by DNase I. Acid hydrolysis released only deoxyribonucleosides. The strand contained 6 guanine, 4 cytosine, 3 adenine, and 3 thymine residues. The core concept tested is base pairing and structural implications of nucleotide composition. Which statement is most consistent with the nucleotide structure described?

A research group synthesized a 12-nt oligonucleotide using standard solid-phase phosphoramidite chemistry. They confirmed that each coupling step adds one nucleotide to the 5′-hydroxyl of the growing chain while the first nucleotide is anchored through its 3′-end to the solid support. The core concept tested is nucleic acid directionality during synthesis. Which statement is most consistent with the nucleotide structure described?