What is 1-4 linkage?

Answer 1

The term "1,4 linkage" or "1→4 linkage" refers to chemical bonding between an atom numbered 1 and an atom numbered 4.

International convention assigns numbers to atoms in molecules where it helps in description and nomenclature.

Example

As a human assembles glucose molecules into the polysaccharide glycogen, each new glucose attaches to the chain by a dehydration reaction between the (alpha) -OH on its carbon number 1 and the -OH on the carbon 4 at the growing end of the chain.

The majority of the bonds between glucose residues in glycogen (and amylopectin and amylose, which are components of starch, synthesized by plants) are thus 1→4 bonds. These bonds are often termed alpha(1→4) linkages.