AP Biologyeasymcq1 pt

Triglycerides are classified as lipids although they are not true polymers. Which statement about their structure best supports this classification?

A.They consist of amino acids joined by peptide bonds and folded into compact shapes.
B.They are nucleotide chains linked by phosphodiester bonds into informational strands.
C.They branch like glycogen but use beta linkages between glucose units.
D.Three fatty acids attach to one glycerol by ester linkages instead of repeating monomer units.

Explanation

Core Concept

A true polymer is a long chain of recurring monomeric subunits joined by one repeated covalent linkage, as seen in polysaccharides, polypeptides, and nucleic acids. A triglyceride instead has a defined three-part architecture: one glycerol molecule esterified to exactly three fatty acid chains, each linkage formed by dehydration. With no repeating monomer chain it fails the polymer criterion, yet its long nonpolar hydrocarbon tails make it strongly hydrophobic, so it is grouped with the lipids alongside phospholipids and steroids.

Correct Answer

DThree fatty acids attach to one glycerol by ester linkages instead of repeating monomer units.

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