Final answer:
A 1-4 alpha-glycosidic bond connects the anomeric carbon of one sugar molecule to the fourth carbon of another, with the OH group below the sugar ring plane, seen in amylose. It is an alpha bond, in contrast to a beta bond where the OH group is above the plane.
Step-by-step explanation:
A 1-4 alpha-glycosidic bond is a type of linkage found in carbohydrates where the anomeric carbon atom of one sugar molecule (carbon number 1) is connected to the fourth carbon atom of another sugar molecule through an oxygen bridge. This bond is formed through a dehydration reaction where water is removed during bond formation. Specifically in alpha-glycosidic bonds, the anomeric hydroxyl group (OH) of the first sugar is below the plane of the sugar ring, resulting in a bond that is called 'alpha'. An example can be seen in amylose, which is a polysaccharide made up of glucose units linked through alpha-1,4-glycosidic bonds, forming a linear chain. In illustrations, these bonds are often depicted as downward facing 'V' shapes to indicate the alpha orientation of the bond.
The anomeric carbon (carbon number 1) is a significant site as it is the carbon atom that forms the new acetal linkage with the -OR group. This linkage defines the glycosidic bond, which, in the case of an alpha bond, is in contrast to a beta bond where the hydroxyl group is above the plane of the sugar ring.