Carbohydrates

1.4 Carbohydrates

Summary

Carbohydrates are built from monosaccharide monomers joined by covalent bonds through dehydration synthesis. The resulting polysaccharides can be linear or branched, and this structural difference is what determines biological function.

Key Definition

Hydrolysis reverses the process, breaking polymers back into monomers by adding water.

These same principles of monomer assembly and disassembly apply to every class of biological macromolecule.

Three key polysaccharides illustrate the structure–function relationship.

Starch

  • Stores energy in plants

Glycogen

  • Stores energy in animals

  • Extensive branching enabling rapid glucose release

Cellulose

  • Forms rigid linear chains that provide structural support in plant cell walls

At a Glance

Polysaccharide Role Structure Location
Starch Stores energy Plants
Glycogen Stores energy Extensive branching enabling rapid glucose release Animals
Cellulose Structural support Rigid linear chains Plant cell walls

Recognizing that all three polymers are composed of the same glucose monomer — yet serve fundamentally different roles — reinforces the central idea that molecular shape and bonding pattern drive biological function.