1.4 Carbohydrates

Monosaccharides are linked by covalent bonds through dehydration synthesis, which removes a water molecule each time a new monomer is added, producing a polysaccharide chain. Polysaccharides are broken down by hydrolysis, which adds a water molecule across each covalent bond to release individual monosaccharides.

Glycogen is highly branched, providing many free ends where enzymes can simultaneously cleave glucose monomers, allowing rapid energy release. Cellulose has a rigid, linear structure suited for structural support rather than quick enzymatic breakdown, so it cannot be mobilized as an energy source efficiently.

The degree of branching in a polysaccharide determines whether it functions primarily in energy storage or structural support. Starch and glycogen are branched to varying degrees, enabling enzymes to access glucose monomers for energy, with glycogen's greater branching allowing faster mobilization. Cellulose is linear and unbranched, forming rigid fibers that provide structural integrity to plant cell walls rather than serving as an energy reserve.