Accurate Macromolecule Structures

Steps:

• Recall definitions: Macromolecules include polysaccharides, nucleic acids, proteins, and lipids with specific monomer compositions and structures.
• Evaluate A: Amylose is a linear chain of α-glucose, unlike branched amylopectin.
• Evaluate B: DNA forms a double helix from two antiparallel nucleotide polymers.
• Evaluate C and D: Check protein quaternary structure and lipid bonding types.

Why B is correct:

• DNA is a double-stranded helix, an association of two polynucleotide polymers linked by hydrogen bonds between nucleotide monomers (adenine-thymine, guanine-cytosine base pairs).

Why the others are wrong:

• A: Amylose is a linear, unbranched polymer of α-glucose; branching occurs in amylopectin.
• C: Haemoglobin consists of four polypeptide chains (proteins from amino acid monomers) each bound to a heme group, not polymers of amino and heme groups.
• D: Triglycerides are esters formed by condensation of glycerol and three fatty acids, not true polymers with repeating monomers.

Final answer: B