Glycogen's high branching sets it apart from starch

Steps:

• Recall glycogen is an animal storage polysaccharide, while starch is plant-based.
• Compare structures: both use α-glucose with 1→4 bonds, but branching differs.
• Note glycogen has branches every 8-12 residues via 1→6 bonds, enabling rapid glucose release.
• Identify branching as the unique feature distinguishing glycogen from starch's mostly linear amylose or less branched amylopectin.

Why A is correct:

• Glycogen's highly branched structure, with α-1,6 linkages every 8-12 glucose units, allows faster enzymatic breakdown than starch's less frequent branching.

Why the others are wrong:

• B: Both glycogen and starch are polysaccharides, so this is shared, not distinguishing.
• C: Both contain α-glucose monomers, making this common to both.
• D: Both have 1→4 glycosidic bonds in their main chains, so this does not differentiate them.

Final answer: A