Question

Define the following term: Glycosidic linkage.

Hint:

A glycosidic linkage is the oxygen bridge (C-O-C bond) that joins two monosaccharide (simple sugar) units together to form a disaccharide or polysaccharide.

Answer 1

Step 1: Take two sugar units.
Consider two monosaccharide (simple sugar) molecules, each carrying \(-OH\) groups.

Step 2: Join them.
The \(-OH\) group of one sugar reacts with the \(-OH\) group of the other sugar.

Step 3: Remove water.
In this reaction a molecule of water is lost (a condensation), leaving an oxygen bridge between the two units.

Step 4: Name the bridge.
This oxygen bridge, a \(C\!-\!O\!-\!C\) bond linking the two sugar units, is called the glycosidic linkage.

Step 5: Note where it is found.
Such linkages hold the units together in disaccharides (like sucrose) and polysaccharides (like starch and cellulose).

Answer: A glycosidic linkage is the \(C\!-\!O\!-\!C\) oxygen bridge that joins two monosaccharide units, formed by loss of a water molecule between their \(-OH\) groups.