Key bonds in viral structure

Steps:

• Identify common components: All viruses contain nucleic acid (DNA or RNA) and protein capsid.
• Determine bonds in nucleic acids: Phosphodiester bonds link nucleotides; hydrogen bonds pair bases.
• Determine bonds in proteins: Peptide bonds link amino acids; disulfide bonds stabilize structure.
• Confirm universality: These bonds (e.g., 1=peptide, 2=phosphodiester, 3=hydrogen) are essential in all viruses.

Why A is correct:

• All viruses require peptide bonds for capsid proteins, phosphodiester bonds for genome, and hydrogen bonds for nucleic acid stability, per virology definitions.

Why the others are wrong:

• B omits hydrogen bonds needed for base pairing in all viral genomes.
• C omits peptide bonds essential for all viral protein coats.
• D omits phosphodiester bonds required for all viral nucleic acids.

Final answer: A