Which of these is a polymer made up of repeating units of smaller molecules?

Cellulose is a polymer composed of long chains of repeating units of glucose molecules linked together by glycosidic bonds. These chains can be quite extensive, leading to the formation of a rigid structure that provides strength to plant cell walls. This characteristic is crucial for plants as it helps maintain their structure and integrity.

In contrast, glucose is a simple sugar and a monosaccharide, serving as a building block rather than a polymer. Fatty acids are components of lipids and do not form long-chain repeating units typical of polymers. Amino acids are the building blocks of proteins, which can form polymers, but they differ in structure and function from polysaccharides like cellulose. Thus, cellulose is distinctly recognized as a polymer, specifically a polysaccharide.